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Sample records for susceptible lettuce cultivars

  1. Evidence for a race-specific resistance factor in some lettuce (Lactuca sativa L.) cultivars previously considered to be universally susceptible to Bremia lactucae regel.

    Science.gov (United States)

    Crute, I R; Lebeda, A

    1981-05-01

    Previously undetected race-specific resistance to Bremia lactucae (downy mildew) was located in many lettuce cultivars hitherto considered to be universally susceptible to this disease. This resistance factor(s) may also be widely distributed in other cultivars known to carry combinations of already recognised factors R1 to R11. Specific virulence to match this resistance is almost invariably present in pathogen collections. This situation may be either a relic of the evolutionary history of the B. lactucae - L. sativa asssociation or may reflect a rare mutation in B. lactucae for avirulence on all but a few specialised L. sativa genotypes.

  2. Selectivity of thiobencarb between two lettuce (Lactuca sativa, L.) cultivars

    International Nuclear Information System (INIS)

    Reiners, S.

    1987-01-01

    Thiobencarb [S-(4-chlorobenzyl)N,N-diethylthiocarbamate] was examined for weed control on muck grown lettuce. Weed control results were erratic though differential lettuce tolerance was observed in the field. This led to the testing of five lettuce cultivars for tolerance to the herbicide. Of the five lettuce cultivars evaluated, two were selected with the widest tolerance differences: Great Lakes 366 (GLA) (tolerant) and Dark Green Boston (BOS) (susceptible). Studies examining the mechanism of thiobencarb tolerance were conducted with these two cultivars. Within four days after the addition of thiobencarb to the nutrient solution, BOS had significant reductions in the foliar dry weight. In addition, growth abnormalities including fused leaves were observed, indicating inhibition early in leaf development. Greater amounts of 14 C-thiobencarb were absorbed from nutrient solution by BOS, likely due to a significantly greater root system at the time of treatment. The greater uptake and accumulation of 14 C-label in the leaves, as well as significantly greater amounts of unmetabolized 14 C-thiobencarb in the foliage of BOS may account for the selectivity observed. A thiobencarb sulfoxide was not identified in these studies. This indicates that the metabolism of thiobencarb in lettuce differs from other members of the thiocarbamate family of herbicides

  3. Responses of Nasonovia ribisnigri (Homoptera: Aphididae) to susceptible and resistant lettuce.

    Science.gov (United States)

    Liu, Yong-Biao; McCreight, James D

    2006-06-01

    Nymphs and alates of aphid Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae) were tested on 10 lettuce cultivars with N. ribisnigri resistance gene Nr and 18 cultivars without the resistance gene in various bioassays. Bioassays used whole plants, leaf discs, or leaf cages to determine susceptibility of commercial lettuce cultivars to N. ribisnigri infestation and to evaluate screening methods for breeding lettuce resistance to N. ribisnigri. Resistant and susceptible plants were separated in 3 d when using whole plant bioassays. Long-term (> or =7 d) no-choice tests using leaf cages or whole plants resulted in no survival of N. ribisnigri on resistant plants, indicating great promise of the Nr gene for management of N. ribisnigri. Effective screening was achieved in both no-choice tests where resistant or susceptible intact plants were tested separately in groups or individually and in choice tests where susceptible and resistant plants were intermixed. Leaf discs bioassays were not suitable for resistance screening. All lettuce cultivars without the resistance gene were suitable hosts for N. ribisnigri, indicating the great importance of this pest to lettuce production and the urgency in developing resistant lettuce cultivars to manage N. ribisnigri.

  4. Uptake kinetics of arsenic by lettuce cultivars under hydroponics ...

    African Journals Online (AJOL)

    Arsenic (As) uptake ability based on kinetic parameters by two lettuce cultivars; Sijibaiye (SJBY) and Texuanyanlingsun (TXYLS) was investigated in nutrient solution containing eight levels of arsenic (As). Depletion of As from solution was monitored over a period of 24 h at regular time to estimate As uptake kinetics of the ...

  5. The effect of co-infestation by conspecific and heterospecific aphids on the feeding behaviour of Nasonovia ribisnigri on resistant and susceptible lettuce cultivars

    OpenAIRE

    Broeke, ten, Cindy J.M.; Dicke, Marcel; Loon, van, Joop J.A.

    2017-01-01

    Aphid saliva can suppress the blocking of sieve elements, a reaction that plants employ to inhibit aphid feeding, but aphid saliva can also elicit plant defence responses. Such plant responses might affect interactions between different aphid species and intraspecifically, e.g. among different biotypes. The objectives of our study were to investigate if feeding behaviour and performance of two biotypes of the lettuce aphid Nasonovia ribisnigri are affected by (1) feeding by the other biotype ...

  6. The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars

    Science.gov (United States)

    Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane, and Little Gem express an incompatible host-pathogen in...

  7. Genetic characterization of resistance to Sclerotinia in lettuce cultivar Eruption

    Science.gov (United States)

    Lettuce drop caused by the fungal pathogens Sclerotinia minor and S. sclerotiorum is a serious disease of lettuce. The use of genetic resistance as part of an integrated lettuce drop management strategy should have a significant economic advantage in mitigating yield loss. Sclerotinia resistance is ...

  8. Produção comercial de cultivares de alface em Bananeiras Marketable production of lettuce cultivars in Bananeiras, Brazil

    Directory of Open Access Journals (Sweden)

    Djail Santos

    2011-12-01

    Full Text Available Um aspecto importante na escolha de cultivares para uma determinada condição ambiental é a determinação da produção comercial, que indica o potencial de produção por área. O objetivo do trabalho foi avaliar a produção comercial de cultivares de alface nas condições de solo e clima de Bananeiras, Paraíba, durante a estação chuvosa. Foram avaliadas oito cultivares (Cindy, Elba, Grand Rapids, Kaesar, Mimosa, Sabrina, Summer Green e Verônica, no delineamento experimental de blocos casualizados, com quatro repetições. As parcelas tinham 27 plantas, espaçadas de 30 cm entre fileiras e entre linhas. Aos 51 dias após o transplante, as plantas foram colhidas e avaliadas quanto à massa fresca total e comercial, massa seca de folhas, número de folhas, diâmetro da planta, índice comercial e produção comercial. Os maiores valores de massa fresca total e comercial, de diâmetro da planta e produção comercial foram verificados para a cultivar Kaesar. Quanto à massa seca, 'Kaesar' e 'Elba' apresentaram os valores mais elevados. Os maiores números de folha foram obtidos com 'Mimosa', 'Elba', 'Sabrina' e 'Summer Green'. As cultivares Grand Rapids, Verônica e Kaesar mostraram-se mais suscetíveis à septoriose, principalmente nas folhas mais velhas. Considerando-se os resultados e a preferência dos consumidores, 'Kaesar' e 'Summer Green' foram as mais promissoras para introdução e testes em áreas de produção comercial de alface.An important issue when choosing cultivars for specific environmental conditions is to estimate the marketable production, which indicates the potential production per area. The objective of this study was to evaluate the marketable production of lettuce cultivars under the soil and climatic conditions of Bananeiras, Paraíba, Brazil, during the rainy season. The experiment was carried out as a complete randomized blocks design with eight cultivars (Cindy, Elba, Grand Rapids, Kaesar, Mimosa, Sabrina

  9. Desempenho de cultivares de alface na região de Manaus Performance of lettuce cultivars in Manaus region

    Directory of Open Access Journals (Sweden)

    Isac N Rodrigues

    2008-12-01

    Full Text Available Na avaliação de cultivares de hortaliças, os rendimentos médios mais elevados nos ensaios de competição, associados a fatores de qualidade, são utilizados como critérios de recomendação para plantio. O presente trabalho teve como objetivo avaliar as cultivares de alface Frisella, Deisy, Tender Green, Lollo Bionda, Itapuã 401, Marisa, Verônica, Banchu New Red Fire e Hortência nas condições climáticas da região de Manaus, sob cultivo protegido e a campo. Foram avaliadas as características: massa fresca total, massa fresca comercial, diâmetro da cabeça e altura. As cultivares de alface Marisa, Itapuã 401 e Hortência são opções mais adequadas para o cultivo protegido e a campo na região, incluindo-se para o cultivo a campo a cultivar Verônica, a qual apresentou a melhor produção na avaliação realizada neste ambiente.In the evaluation of vegetable cultivars, the high average yield in the competition assays associated to quality factors are utilized as criteria to recommend cultivars. In the present work we evaluated the lettuce cultivars Frisella, Deisy, Tender Green, Lollo Bionda, Itapuã 401, Marisa, Verônica, Banchu New Red Fire and Hortência under the climatic conditions of the region of Manaus, under protected and conventional cultivation. The evaluated characteristics were: total and commercial weight, plant diameter and height. The lettuce cultivars Marisa, Itapuã 401 and Hortência presented higher production in both environments adding Verônica with best production under conventional cultivation.

  10. Characterization of Verticillium dahliae disease reactions in lettuce differential cultivars

    Science.gov (United States)

    Soilborne diseases significantly affect high value crops in coastal California, including lettuce and strawberry. Breeding crops for pathogen resistance is a strategy for the sustainable management of crop disease. Verticillium dahliae is a soilborne fungus that causes wilt and economic losses in a ...

  11. Growth of Three Lettuce Cultivars in NASA's HDU PEM During the 2010 DRATS Test

    Science.gov (United States)

    Stutte, Gary W.; Newsham, Gerard; Wheeler, Raymond

    2011-01-01

    NASA's 2010 Desert Research and Technology Studies (DRATS) of the VEGGIE Food Production System in the Habitat Demonstration Unit (HDU) Pressurized Excursion Module (PEM) was the first operational evaluation of salad crop production technology in a NASA analog test. Rooting media and slow release fertilizers were evaluated for three lettuce cultivars that had shown promise as candidates for a surface based food production system. These tests involved comparing growth, color and quality of the lettuce cultivars grown under VEGGIE LED array (Orbitec, Madison, WI) or Biomass Production System for Education ((BSEe), Orbitec, Madison, WI) compact fluorescent lamps using a gravity feed water delivery system. Mission relevant conditions of CO2, temperature and RH were maintained using controlled environment chambers (EGC, Chagrin Falls, OH). Growth data was obtained for the two red leaf lettuce cultivars, Outredgeous and Firecracker, and the green Bibb lettuce cultivar, Flandria. Growth and quality was evaluated using different concentrations (7.5 g/L and 15 g/L) of commercial slow release fertilizer (Osmocote Plus 15-9-12, Scotts, Maryville, OH) and Nutricote 18-6-8 (Florikan, Sarasota, FL) in either a peat/vermiculite media (sunshine LP5 MiX, Sungro, Bellview, WA) or calcined montmorillonite clay [(arcillite,)Turface Proleague, Profile LLC, Buffalo Grove, IL]. The commercial peat/vermiculite mix generally resulted in larger plants than those grown in arcillite. Increasing the concentration of Osmocote from 7.5 to 15 g/L increased the height, dry mass, and leaf area of lettuce cultivars. In contrast, there was a decrease in growth parameters when concentration of Nutricote was increased from 7.5 to 15 g/L. The best growth was obtained with the 7.5 g/L Nutricote using a commercial peat/vermiculite mixture. This media was used for field testing VEGGIE plant system in the 2010 DRAT test. The VEGGIE nutrient delivery system worked well, was able to be maintained by multiple

  12. Nitrogen oxides produced during CO/sub 2/ enrichment. II. Effects on different tomato and lettuce cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, L.M.

    1985-01-01

    Eight cultivars of Lycopersicon esculentum (tomato) and six cultivars of Lactuca sativa (lettuce) were subjected to CO/sub 2/-enriched air (1000 ..mu..l l/sup -1/) containing 0.7 or 0.9 ..mu..l l/sup -1/ nitrogen oxides (NO/sub x/). CO/sub 2/ enrichment without NO/sub x/ significantly increased the dry weight of all tomato (35-81%) and lettuce cultivars (25-101%). In six of the eight tomato cultivars the dry weight was reduced by the addition of NO/sub x/. The mean relative growth rate (RGR) decreased by 4-19% depending on the cultivar. This meant that the benefit of CO/sub 2/ enrichment was almost completely eliminated in most of the cultivars. Marginal leaf necrosis appeared in some of the cultivars, while in others no visible injury developed. None of the lettuce cultivars was significantly affected by the addition of NO/sub x/. 16 references, 4 tables.

  13. Development of genomic SSR markers for fingerprinting lettuce (Lactuca sativa L.) cultivars and mapping genes.

    Science.gov (United States)

    Rauscher, Gilda; Simko, Ivan

    2013-01-22

    Lettuce (Lactuca sativa L.) is the major crop from the group of leafy vegetables. Several types of molecular markers were developed that are effectively used in lettuce breeding and genetic studies. However only a very limited number of microsattelite-based markers are publicly available. We have employed the method of enriched microsatellite libraries to develop 97 genomic SSR markers. Testing of newly developed markers on a set of 36 Lactuca accession (33 L. sativa, and one of each L. serriola L., L. saligna L., and L. virosa L.) revealed that both the genetic heterozygosity (UHe = 0.56) and the number of loci per SSR (Na = 5.50) are significantly higher for genomic SSR markers than for previously developed EST-based SSR markers (UHe = 0.32, Na = 3.56). Fifty-four genomic SSR markers were placed on the molecular linkage map of lettuce. Distribution of markers in the genome appeared to be random, with the exception of possible cluster on linkage group 6. Any combination of 32 genomic SSRs was able to distinguish genotypes of all 36 accessions. Fourteen of newly developed SSR markers originate from fragments with high sequence similarity to resistance gene candidates (RGCs) and RGC pseudogenes. Analysis of molecular variance (AMOVA) of L. sativa accessions showed that approximately 3% of genetic diversity was within accessions, 79% among accessions, and 18% among horticultural types. The newly developed genomic SSR markers were added to the pool of previously developed EST-SSRs markers. These two types of SSR-based markers provide useful tools for lettuce cultivar fingerprinting, development of integrated molecular linkage maps, and mapping of genes.

  14. susceptibility of some kersting's groundnut landrace cultivars

    African Journals Online (AJOL)

    User

    ABSTRACT: Seeds of five different landrace cultivars of Kersting's groundnut, Macrotyloma geocarpum. (Harms) Marechal and Baudet, obtained from northern Ghana, were evaluated for their suscep- tibility to infestation and damage by the pulse beetle, Callosobruchus maculatus Fab. The com- pletely randomized design ...

  15. Desempenho de cultivares de alface no Estado do Acre Performance of lettuce cultivars in the State of Acre, Brazil

    Directory of Open Access Journals (Sweden)

    Francisco J. da S. Lédo

    2000-11-01

    lisa, apresentando folhas de tamanho uniforme e bem arranjadas. Entre as de folha crespa solta destacaram-se as cultivares. Verônica e Marisa. A cultivar Lucy Brown do tipo americana (crisp head também foi bastante produtiva.Due to the environmental conditions verified in the state of Acre, characterized by the occurrence of high temperatures and precipitation, cultivars traditionally used by the producers present low yield and poor quality. The aim of the present work was to evaluate the behavior of the new lettuce cultivars available in the market, in terms of agronomic characteristics and yield, in the climatic and soil conditions of Rio Branco. Two trials were accomplished in the Embrapa Acre experimental farm, in a dark red claysoil, of loamy texture. The first from May to July 1996 (dry season and the second from December 1996 to February 1997 (rainy season. The cultivars Babá de Verão, Brisa, Carolina AG-576, Elisa, Lucy Brown, Marisa AG-216, Piracicaba 65, Regina 71, Tainá, Simpson, Vanessa and Verônica were evaluated. 'Regina 71' and 'Elisa' were only included on the dry season trial. The experimental design was a randomized block, with three replications. During the dry season, the cultivars Simpson, Lucy Brown and Regina 71 presented the largest average weights (373; 362 and 341 g, respectively and commercial yields (49.8; 48.3 and 45.5 t/ha, respectively. In general, the cultivars with smooth leaves with or without head presented larger nematoid (Meloidogyne javanica attack index, when compared to the curly type ones. In the rainy season trials, the cultivars Marisa AG-216, Verônica, Lucy Brown, Brisa, Tainá and Piracicaba-65 presented the greatest average weights and commercial yields. However, the obtained averages were very inferior to that verified in the trials of the dry period, varying from 164 to 198 g for average weight, and from 21.9 to 25.9 t/ha for commercial yield. Of those cultivars tested on the dry season, Regina 71 (butter head

  16. Genome-wide association study for lettuce cultivars with improved salad processing efficiency

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is widely used as the main ingredient of packaged leafy vegetable salads. Salad lettuce can have short shelf life, decaying as early as eight days after harvest and reducing the nutritional quality. Decayed lettuce is not marketable, produces extra waste, and results in t...

  17. Genotype variations in cadmium and lead accumulations of leafy lettuce (Lactuca sativa L.) and screening for pollution-safe cultivars for food safety.

    Science.gov (United States)

    Zhang, Kun; Yuan, Jiangang; Kong, Wei; Yang, Zhongyi

    2013-06-01

    Heavy-metals in polluted soils can accumulate in plants and threaten crop safety. To evaluate the risk of heavy-metal pollution in leafy lettuce (Lactuca sativa L.), two pot experiments were conducted to investigate Cd and Pb accumulation and transfer potential in 28 cultivars of lettuce and to screen for low-Cd and low-Pb accumulative cultivars. In the three treatments, 5.2-fold, 4.8-fold and 4.8-fold differences in the shoot Cd concentration were observed between the cultivars with the highest and the lowest Cd concentrations, respectively. This genotype variation was sufficiently large to identify low-Cd accumulative genotypes to reduce Cd contamination in food. Cadmium accumulation in the low-Cd accumulative genotypes was significantly positively correlated with Pb accumulation. At the cultivar level, Cd and Pb accumulation in lettuce was stable and genotype-dependent. High Pb soil levels did not affect shoot Cd accumulation in lettuce. Lettuce was concluded to be at high risk for Cd pollution and low risk for Pb pollution. Among the tested cultivars, cvs. SJGT, YLGC, N518, and KR17 had the lowest Cd and Pb accumulation abilities in shoots and are thus important parental material for breeding pollution-safe cultivars to minimize Cd and Pb accumulation.

  18. Effect of supplemental ultraviolet radiation on the concentration of phytonutrients in green and red leaf lettuce (Lactuca sativa) cultivars

    Science.gov (United States)

    Britz, Steven; Caldwell, Charles; Mirecki, Roman; Slusser, James; Gao, Wei

    2005-08-01

    Eight cultivars each of red and green leaf lettuce were raised in a greenhouse with supplemental UV radiation, either UV-A (wavelengths greater than ca. 315 nm) or UV-A+UV-B (wavelengths greater than ca. 290 nm; 6.4 kJ m-2 daily biologically effective UV-B), or no supplemental UV (controls). Several phytonutrients were analyzed in leaf flours to identify lines with large differences in composition and response to UV-B. Red leaf lettuce had higher levels of phenolic acid esters, flavonols and anthocyanins than green lines. Both green and red lines exposed to UV-B for 9 days showed 2-3-fold increases in flavonoids compared to controls, but only 45% increases in phenolic acid esters, suggesting these compounds may be regulated by different mechanisms. There were large differences between cultivars in levels of phenolic compounds under control conditions and also large differences in UV-B effects. Among red varieties, cv. Galactic was notable for high levels of phenolics and a large response to UV-B. Among green varieties, cvs. Black-Seeded Simpson and Simpson Elite had large increases in phenolics with UV-B exposure. Photosynthetic pigments were also analyzed. Green leaf lettuce had high levels of pheophytin, a chlorophyll degradation product. Total chlorophylls (including pheophytin) were much lower in green compared to red varieties. Lutein, a carotenoid, was similar for green and red lines. Total chlorophylls and lutein increased 2-fold under supplemental UV-B in green lines but decreased slightly under UV-B in red lines. Lettuce appears to be a valuable crop to use to study phytochemical-environment interactions.

  19. Evaluation of Local Wheat Cultivars Susceptibility to infection with Black Stem Rust

    International Nuclear Information System (INIS)

    Batta, Y.A.

    2007-01-01

    The present study was conducted to assess the susceptibility of seven local wheat cultivars from Palestine to infection with black stem rust caused by Puccinia graminis f. sp. tritici. Two techniques of disease inoculation were applied during bioassays: global inoculation of entire wheat plants with urediospores and localized inoculation with urediospores and localized inoculation with urediospores on wheat leaf-pieces incubated under humid conditions. Susceptibility of tested cultivars was evaluated according to disease scale based on number and size of typical unredial pustules that appeared after inoculation on entire plants or leaf pieces. Results obtained on bioassay of susceptibility and disease rating on entire plants indicated that Anbar, Kamata and Hetiya safra cultivars were the least susceptible to P. g. tritici infection, whereas Debiya beda cultivar was the most susceptible. The other tested cultivars such as Nab-El-Jama, sawda and Senf 870 were moderately susceptible. On leaf-pieces, Anbar and Kamatat were the least susceptible cultivars, whereas Debiya beda and Nab-El-Jamal were the most susceptible cultivars. The other tested cultivars such as Debiya swada, Senf 870 and Hetiya safra were moderately susceptible. Significant reductions were obtained for the size of unredial postules formed on leaf-pieces when inoculated in an unwounded state compared to the wounded indicating the importance of wounds during inoculation. The global results indicated the possibility of using above method of disease inoculating, scaling and rating for evaluation of wheat cultivars susceptibility for the eventual use in breeding program for resistant varieties in Palestine. (author)

  20. Competição de cultivares de alface sob cultivo hidropônico 'NFT' em três diferentes espaçamentos Butterhead lettuce cultivars under 'NFT' hydroponic cultivation in three different spacings

    Directory of Open Access Journals (Sweden)

    Ronan Gualberto

    1999-07-01

    Full Text Available Com o objetivo de avaliar o desempenho de seis cultivares de alface do tipo lisa (Babá de Verão, Brasil 303, Elisa, Karla, Lívia e Monalisa em três espaçamentos (25 x 20, 25 x 25 e 25 x 30 cm, cultivadas em sistema hidropônico 'NFT', realizou-se um experimento na Fazenda Experimental da Universidade de Marília (SP, no período de 23 de setembro a 21 de novembro de 1997. Foram avaliadas as características comprimento de caule, produção de matéria fresca por planta e por área e produção de matéria seca da parte aérea, da raiz e total. O delineamento experimental adotado foi o de blocos casualizados, em esquema fatorial 6 x 3, com três repetições. Não houve efeito significativo da interação entre cultivares e espaçamentos. As cultivares Babá de Verão, Lívia e Elisa se destacaram pela produção de matéria fresca e matéria seca total. As cultivares Monalisa e Karla mostraram-se menos suscetíveis ao pendoamento precoce, enquanto a 'Babá de Verão' foi a mais suscetível. Não foi verificada influência significativa dos espaçamentos sobre as características estudadas, exceto para a produção por área, onde independente das cultivares utilizadas, o espaçamento 25 x 20 propiciou uma produção de 4,465 Kg/m², superior aos demais espaçamentos utilizados. Assim. Produções significativamente inferiores foram obtidas nos tratamentos 25 x 25 cm e 25 x 30 cm: 3,583 e 3,304 Kg/m², respectivamente, devido à redução no número de plantas por m².An experiment was carried out at the Experimental Farm, of Marília University, from September 23th 1997 to November 21st 1997 with the objective of evaluating the performance of six butterhead lettuce cultivars (Babá de Verão, Brasil 303, Elisa, Karla, Lívia and Monalisa in three spacings (25 x 20, 25 x 25 and 25 x 30 cm, cultivated under a hydroponic system 'NFT'. Stem length, fresh matter yield per plant and per area, and aerial part and root dry matter weight were

  1. Studies on the susceptibility of peas and field peas cultivars to Ascochyta pisi (Lib.

    Directory of Open Access Journals (Sweden)

    Helena Furgał-Węgrzycka

    2013-12-01

    Full Text Available The aim of the work was to find the plants resistant to Ascochyta pisi causing leaf and spot-pot of peas and field peas. Fourty five cultivars of peas and field peas and 6 breeding materials were tested in field in the period 1975-1978. Cultivars: Bartel, Birte, Borek, Cebeco, Finale and Paloma were to be less susceptible. In laboratory and greenhouse conditions peas and field peas cultivares were examined for susceptible to pathotypes 2 and 4 of Ascochyta pisi. The results obtained proved that cultivars: Borel, cebeco, Finale and Paloma were to be less susceptible to two pathotypes of Ascochyta pisi.

  2. Authenticity of old cultivars in genebank collections: a case study on lettuce

    NARCIS (Netherlands)

    Wouw, van de M.J.; Treuren, van R.; Hintum, van T.J.L.

    2011-01-01

    Ex situ collections in genebanks conserve many old cultivars that had disappeared from mainstream agriculture before modern genebanks were established. The collections incorporated cultivars from many sources, such as botanical gardens and working collections, sometimes with little further

  3. Allelopathic Activity of Extracts from Different Brazilian Peanut (Arachis hypogaea L.) Cultivars on Lettuce (Lactuca sativa) and Weed Plants.

    Science.gov (United States)

    Casimiro, G S; Mansur, E; Pacheco, G; Garcia, R; Leal, I C R; Simas, N K

    2017-01-01

    Peanut ( Arachis hypogaea L.) is the fourth most consumed oleaginous plant in the world, producing seeds with high contents of lipids, proteins, vitamins, and carbohydrates. Biological activities of different extracts of this species have already been evaluated by many researchers, including antioxidant, antitumoral, and antibacterial. In this work, the allelopathic activity of extracts from different Brazilian peanut cultivars against lettuce (Lactuca sativa) and two weed plants ( Commelina benghalensis and Ipomoea nil ) was studied. Aerial parts, roots, seeds, and seed coats were used for the preparation of crude extracts. Seed extract partitioning was performed with n -hexane, dichloromethane, ethyl acetate, n -butanol, and aqueous residue. Germination and growth of hypocotyls and rootlets were evaluated after one and five days of incubation with plant extracts, respectively. Crude seed extract and its dichloromethanic partition displayed highest allelopathic activity. These results contribute for the study of new potential natural herbicides.

  4. Allelopathic Activity of Extracts from Different Brazilian Peanut (Arachis hypogaea L.) Cultivars on Lettuce (Lactuca sativa) and Weed Plants

    Science.gov (United States)

    Garcia, R.; Simas, N. K.

    2017-01-01

    Peanut (Arachis hypogaea L.) is the fourth most consumed oleaginous plant in the world, producing seeds with high contents of lipids, proteins, vitamins, and carbohydrates. Biological activities of different extracts of this species have already been evaluated by many researchers, including antioxidant, antitumoral, and antibacterial. In this work, the allelopathic activity of extracts from different Brazilian peanut cultivars against lettuce (Lactuca sativa) and two weed plants (Commelina benghalensis and Ipomoea nil) was studied. Aerial parts, roots, seeds, and seed coats were used for the preparation of crude extracts. Seed extract partitioning was performed with n-hexane, dichloromethane, ethyl acetate, n-butanol, and aqueous residue. Germination and growth of hypocotyls and rootlets were evaluated after one and five days of incubation with plant extracts, respectively. Crude seed extract and its dichloromethanic partition displayed highest allelopathic activity. These results contribute for the study of new potential natural herbicides. PMID:28396881

  5. Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State

    OpenAIRE

    Firmino,Ana Carolina; Krause-Sakate,Renate; Pavan,Marcelo Agenor; Silva,Norberto da; Hanai,Sérgio Minoru; Anbo,Roberto Hiroto; Nietzsche,Thomas; Le Gall,Olivier

    2008-01-01

    LMV is one of the most important pathogens of lettuce worldwide. Based on their ability to overcome the resistance genes mo1¹ and mo1² in lettuce, isolates can be divided in two types: LMV-Most, which can infect and are seed-borne in cultivars containing the mo1 gene and LMV-Common, which do not cause symptoms on these cultivars and are seed transmitted only in susceptible cultivars. To evaluate the occurrence of these two types of LMV isolates, a survey was carried out during 2002-2005 in th...

  6. Variability in Susceptibility to Anthracnose in the World Collection of Olive Cultivars of Cordoba (Spain).

    Science.gov (United States)

    Moral, Juan; Xaviér, Carlos J; Viruega, José R; Roca, Luis F; Caballero, Juan; Trapero, Antonio

    2017-01-01

    Anthracnose of olive ( Olea europaea ssp. europaea L.), caused by Colletotrichum species, is a serious disease causing fruit rot and branch dieback, whose epidemics are highly dependent on cultivar susceptibility and environmental conditions. Over a period of 10 years, there have been three severe epidemics in Andalusia (southern Spain) that allowed us to complete the assessment of the World Olive Germplasm Bank of Córdoba, one of the most important cultivar collections worldwide.A total of 308 cultivars from 21 countries were evaluated, mainly Spain (174 cvs.), Syria (29 cvs.), Italy (20 cvs.), Turkey (15 cvs.), and Greece (16 cvs.). Disease assessments were performed using a 0-10 rating scale, specifically developed to estimate the incidence of symptomatic fruit in the tree canopy. Also, the susceptibility of five reference cultivars was confirmed by artificial inoculation. Because of the direct relationship between the maturity of the fruit and their susceptibility to the pathogen, evaluations were performed at the end of fruit ripening, which forced coupling assessments according to the maturity state of the trees. By applying the cluster analysis to the 308 cultivars, these were classified as follows: 66 cvs. highly susceptible (21.4%), 83 cvs. susceptible (26.9%), 66 cvs. moderately susceptible (21.4%), 61 cvs. resistant (19.8%), and 32 cvs. highly resistant (10.4%). Representative cultivars of these five categories are "Ocal," "Lechín de Sevilla," "Arbequina," "Picual," and "Frantoio," respectively. With some exceptions, such as cvs. Arbosana, Empeltre and Picual, most of the Spanish cultivars, such as "Arbequina," "Cornicabra," "Hojiblanca," "Manzanilla de Sevilla," "Morisca," "Picudo," "Farga," and "Verdial de Huévar" are included in the categories of moderately susceptible, susceptible or highly susceptible. The phenotypic evaluation of anthracnose reaction is a limiting factor for the selection of olive cultivars by farmers, technicians, and breeders.

  7. Interaction of Vesicular-Arbuscular Mycorrhizae and Cultivars of Alfalfa Susceptible and Resistant to Meloidogyne hapla.

    Science.gov (United States)

    Grandison, G S; Cooper, K M

    1986-04-01

    The interaction between vesicular-arbuscular mycorrhizal (VAM) fungi and the root-knot nematode (Meloidogyne hapla) was investigated using both nematode-susceptible (Grasslands Wairau) and nematode-resistant (Nevada Synthetic XX) cultivars of alfalfa (Medicago sativa) at four levels of applied phosphate. Mycorrhizal inoculation improved plant growth and reduced nematode numbers and adult development in roots in dually infected cultures of the susceptible cultivar. The tolerance of plants to nematode infection and development when preinfected with mycorrhizal fungi was no greater than when they were inoculated with nematodes and mycorrhizal fungi simultaneously. Growth of plants of the resistant cultivar was unaffected by nematode inoculation but was improved by mycorrhizal inoculation. Numbers of nematode juveniles were lower in the roots of the resistant than of the susceptible cultivar and were further reduced by mycorrhizal inoculation, although no adult nematodes developed in any resistant cultivar treatment. Inoculation of alfalfa with VAM fungi increased the tolerance and resistance of a cultivar susceptible to M. hapla and improved the resistance of a resistant cultivar.

  8. The influence of the microbial quality of wastewater, lettuce cultivars and enumeration technique when estimating the microbial contamination of wastewater-irrigated lettuce.

    Science.gov (United States)

    Makkaew, P; Miller, M; Cromar, N J; Fallowfield, H J

    2017-04-01

    This study investigated the volume of wastewater retained on the surface of three different varieties of lettuce, Iceberg, Cos, and Oak leaf, following submersion in wastewater of different microbial qualities (10, 10 2 , 10 3 , and 10 4 E. coli MPN/100 mL) as a surrogate method for estimation of contamination of spray-irrigated lettuce. Uniquely, Escherichia coli was enumerated, after submersion, on both the outer and inner leaves and in a composite sample of lettuce. E. coli were enumerated using two techniques. Firstly, from samples of leaves - the direct method. Secondly, using an indirect method, where the E. coli concentrations were estimated from the volume of wastewater retained by the lettuce and the E. coli concentration of the wastewater. The results showed that different varieties of lettuce retained significantly different volumes of wastewater (p 0.01) were detected between E. coli counts obtained from different parts of lettuce, nor between the direct and indirect enumeration methods. Statistically significant linear relationships were derived relating the E. coli concentration of the wastewater in which the lettuces were submerged to the subsequent E. coli count on each variety the lettuce.

  9. Relative Susceptibility of Quince, Pear, and Apple Cultivars to Fire Blight Following Greenhouse Inoculation

    Science.gov (United States)

    Fire blight caused by Erwinia amylovora (EA) is one of the most serious diseases of plants in the family Rosaceae, and Quince (Cydonia oblonga Mill.) is considered one of the most susceptible host genera. Apple (Malus sp.) and pear (Pyrus sp.) cultivars ranging from most susceptible to most resistan...

  10. Cell wall alterations in the leaves of fusariosis-resistant and susceptible pineapple cultivars.

    Science.gov (United States)

    de Farias Viégas Aquije, Glória Maria; Zorzal, Poliana Belisário; Buss, David Shaun; Ventura, José Aires; Fernandes, Patricia Machado Bueno; Fernandes, Antonio Alberto Ribeiro

    2010-10-01

    Fusariosis, caused by the fungus Fusarium subglutinans f. sp. ananas (Syn. F. guttiforme), is one of the main phytosanitary threats to pineapple (Ananas comosus var. comosus). Identification of plant cell responses to pathogens is important in understanding the plant-pathogen relationship and establishing strategies to improve and select resistant cultivars. Studies of the structural properties and phenolic content of cell walls in resistant (Vitoria) and susceptible (Perola) pineapple cultivars, related to resistance to the fungus, were performed. The non-chlorophyll base of physiologically mature leaves was inoculated with a conidia suspension. Analyses were performed post-inoculation by light, atomic force, scanning and transmission electron microscopy, and measurement of cell wall-bound phenolic compounds. Non-inoculated leaves were used as controls to define the constitutive tissue characteristics. Analyses indicated that morphological differences, such as cell wall thickness, cicatrization process and lignification, were related to resistance to the pathogen. Atomic force microscopy indicated a considerable difference in the mechanical properties of the resistant and susceptible cultivars, with more structural integrity, associated with higher levels of cell wall-bound phenolics, found in the resistant cultivar. p-Coumaric and ferulic acids were shown to be the major phenolics bound to the cell walls and were found in higher amounts in the resistant cultivar. Leaves of the resistant cultivar had reduced fungal penetration and a faster and more effective cicatrization response compared to the susceptible cultivar.

  11. Genotypic variation and mechanism in uptake and translocation of perfluorooctanoic acid (PFOA) in lettuce (Lactuca sativa L.) cultivars grown in PFOA-polluted soils.

    Science.gov (United States)

    Xiang, Lei; Chen, Lei; Yu, Le-Yi; Yu, Peng-Fei; Zhao, Hai-Ming; Mo, Ce-Hui; Li, Yan-Wen; Li, Hui; Cai, Quan-Ying; Zhou, Dong-Mei; Wong, Ming-Hung

    2018-05-02

    The cultivation of crop cultivars with low pollutant accumulation is an important strategy to reduce the potential health risks of food produced from polluted soils. In this study, we identified three loose-leaf lettuce cultivars with low accumulation of perfluorooctanoic acid (PFOA), a highly toxic and persistent organic pollutant. PFOA concentrations in the shoots of low-PFOA cultivars were 3.7-5.5-fold lower than those of high-PFOA cultivars. The identification of low-PFOA cultivars could contribute to ensuring food safety despite cultivation in highly polluted soils (1 mg/kg) based on the tolerable daily PFOA intake (1.5 μg/kg/d). We detected lower desorbing fractions of PFOA in rhizosphere soil, lower bioconcentration factors, and higher distribution in the cell walls and organelles of roots in low-PFOA cultivars, all of which are key factors in limiting PFOA uptake and translocation from soil to shoots, than in high-PFOA cultivars. This study reveals the mechanism of PFOA uptake from soil to crop and lays a foundation for establishing a cost-effective strategy to plant crops in polluted soil and reduce exposure risk due to persistent organic pollutants in crops. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Resistance to downy mildew in lettuce ‘La Brillante’ is conferred by dm50 gene and multiple QTL

    Science.gov (United States)

    Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar La Brillante has a high level of field resistance to the disease in California. Testing of a mapping popu...

  13. Susceptibility of different parsley cultivars to infestation by pathogenic fungi

    Directory of Open Access Journals (Sweden)

    Jacek Nawrocki

    2012-12-01

    Full Text Available The experiments were carried out in the years 2002 and 2003 on parsley seeds of 6 cultivars: Alba, Berlińska, Cukrowa, Kinga, Lenka, and Vistula. Mycological analysis of parsley seeds showed that the most common inhabitans were fungi from genus Alternaria (mainly A. alternata and A. radicina and Fusarium, especially F. avenaceum and F. oxysporum. During the glasshouse investigations fungi Alternaria radicina, A. alternata and Fusarium avenaceum were the main reason for parsley damping-off. The highest number of infected seedlings was observed for Berlińska and Kinga, because in both years of experiments these cultivars had the lowest number of healthy seedlings. The highest number of healthy seedlings had cultivars Alba and Lenka, especially in the second year of experiments. In the field experiments not only fungi from genus Alternaria and Fusarium were the most often isolated from diseased parsley seedlings. Fusarium oxysporum was more often isolated from diseased field seedlings than from glasshouse parsley seedlings. Other fungies isolated often from parsley seedlings cultivated in the field were: Pythium spp., Rhizoctonia solani, Cylindrocarpon destructans and Stemphylium botryosum.

  14. Blueberry Cultivars Differ in Susceptibility to the Elephant Weevil, Orthorhinus cylindrirostris (Coleoptera: Curculionidae).

    Science.gov (United States)

    Murdoch, Gregory; Clift, Alan D; Mansfield, Sarah

    2017-10-01

    The accumulated damage from elephant weevil larvae, Orthorhinus cylindrirostris (F.) (Coleoptera: Curculionidae), reduces blueberry yield and shortens the productive lifespan of blueberry plants by several years. Selective breeding to develop pest-resistant blueberry cultivars is a possible control option, but the relationship between O. cylindrirostris populations, plant damage, and blueberry yield has not been described. A field survey of 17 blueberry cultivars was conducted on a commercial farm to measure O. cylindrirostris populations (emergence holes and adult numbers) and yield from plants of different ages (2-12 yr). Blueberry plants accumulated damage over time, that is, older plants tended to have more O. cylindrirostris emergence holes than younger plants. All cultivars received some level of O. cylindrirostris attack but this did not always lead to yield losses. Newer cultivars that have been in production since 2000 were less susceptible to O. cylindrirostris than older cultivars. Removal of highly susceptible cultivars from commercial blueberry farms may reduce O. cylindrirostris populations. There is potential for selective breeding to increase plant resistance to O. cylindrirostris if the specific resistance mechanisms can be identified in blueberry. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Resistance and susceptibility of alfalfa (Medicago sativa L.) cultivars to the aphid Therioaphis maculata (Homoptera:Aphididae): insect biology and cultivar evaluation

    Institute of Scientific and Technical Information of China (English)

    ALEXANDRE DE ALMEIDA E SILVA; ELENICE MOURO VARANDA; JOS(E) RICARDO BAROSELA

    2006-01-01

    Biology of the aphid Therioaphis maculata was studied on alfalfa (Medicago sativa L.), including four resistant (Mesa-Sirsa, CUF101, Baker and Lahontan) and two susceptible (ARC and Caliverde) alfalfa cultivars, and one of the most cropped Brazilian cultivars, Crioula. Under controlled conditions, antibiosis (i.e., reduced longevity, fecundity and increased mortality of the aphid) was observed mainly on the resistant alfalfa cultivars,except on Lahontan. Crioula seemed to be tolerant to aphids. Present data support geographic limitation usage of cultivars, and we suggest Baker and Mesa-Sirsa as sources of antibiosis,and provide biological information of a tropical T. maculata biotype on alfalfa.

  16. A dose-response relationship for marketable yield reduction of two lettuce (Lactuca sativa L.) cultivars exposed to tropospheric ozone in Southern Europe.

    Science.gov (United States)

    Marzuoli, Riccardo; Finco, Angelo; Chiesa, Maria; Gerosa, Giacomo

    2017-12-01

    The present study investigated the response to ozone (O 3 ) of two cultivars (cv.'Romana' and cv. 'Canasta') of irrigated lettuce grown in an open-top chamber (OTC) experiment in Mediterranean conditions. Two different levels of O 3 were applied, ambient O 3 in non-filtered OTCs (NF-OTCs) and -40% of ambient O 3 in charcoal-filtered OTCs (CF-OTCs), during four consecutive growing cycles. At the end of each growing cycle, the marketable yield (fresh biomass) was assessed while during the growing periods, measurements of the stomatal conductance at leaf level were performed and used to define a stomatal conductance model for calculation of the phytotoxic ozone dose (POD) absorbed by the plants.Results showed that O 3 caused statistically significant yield reductions in the first and in the last growing cycle. In general, the marketable yield of the NF-OTC plants was always lower than the CF-OTC plants for both cultivars, with mean reductions of -18.5 and -14.5% for 'Romana' and 'Canasta', respectively. On the contrary, there was no statistically significant difference in marketable yield due to the cultivar factor or to the interaction between O 3 and cultivar in any of the growing cycle performed.Dose-response relationships for the marketable relative yield based on the POD values were calculated according to different flux threshold values (Y). The best regression fit was obtained using an instantaneous flux threshold of 6 nmol O 3 m -2  s -1 (POD 6 ); the same value was obtained also for other crops. According to the generic lettuce dose-response relationship, an O 3 critical level of 1 mmol O 3 m -2 of POD 6 for a 15% of marketable yield loss was found.

  17. Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew [Podosphaera leucotricha (Ell. et Ev. Salmon

    Directory of Open Access Journals (Sweden)

    Zbigniew Borecki

    2013-12-01

    Full Text Available Field susceptibility of 13 scab-resistant apple cultivars to apple powdery mildew was evaluated in 1983-1986. Four groups of susceptibility were distinguished. None of the 13 tested scab-resistant apple trees exhibited complete field immunity to apple powdery mildew. Two cultivars, 'Prima' and 'Primula', were practically resistant. 'Liberty' and two numbered selections, NY-140-9 and NY-158-2, belonged to the group of lower susceptibility. Moderate susceptibility was shown by: 'Novamac', 'Freedom', 'Gavin', 'Prima' and 'Florina'. The group of apple trees most susceptible to Podosphaera leucotricha included: 'Macfree', 'Priscilla' and 'Nova Easygro'. It is not necessary to use chemical sprays to control powdery mildew on 'Prima' and 'Primula'. A reduced spraying program may be recommended only under high disease pressure on less susceptible apple cultivars. A regular spray schedule is needed on moderately susceptible apple trees, but improved chemical control is necessary on the most susceptible ones.

  18. Desempenho de cultivares de alface tipo americana em cultivo de outono no sul de Minas Gerais Performance of iceberg lettuce cultivars in south of Minas Gerais under autumn condition

    Directory of Open Access Journals (Sweden)

    Jony Eishi Yuri

    2004-04-01

    Full Text Available Com o objetivo de avaliar o desempenho de cultivares de alface tipo americana (Lactuca sativa L. em cultivo de outono, foi conduzido um experimento no município de Santana da Vargem, MG, no período de março a junho de 2002. Utilizou-se o delineamento de blocos ao acaso com treze tratamentos (cultivares Adal, 4553 R7, AEL 10, Iglo, Rocco RZ, Rubette, RX 66, RPT 3030, RPT 2020, Paloma, Sandy, Legacy e Raider e três repetições. As cultivares 45-53R7, RPT 2020, Paloma, Raider e RPT 3030 apresentaram massa fresca total estatisticamente maiores que as demais cultivares, com produtividades de 1.016,9; 1.029,4; 1.044,9; 1.075,2 e 1.105,2 g planta-1, respectivamente. As cultivares 45-53R7, RPT 2020, Paloma, Raider, RPT 3030, AEL 10 e Rocco, com produtividade de massa fresca comercial oscilando entre 599,1 a 739,1 g planta-1, foram estatisticamente mais produtivas que as demais cultivares. A cultivar 45-53R7, com circunferência de cabeça comercial de 49,2 cm, sobressaiu-se das demais. Não houve diferenças significativas entre os materiais quanto ao comprimento de caule. Quanto à simetria da cabeça comercial, as cultivares RPT 2020, Raider e RPT 3030, com notas 4,6; 5,0 e 5,0, respectivamente, foram mais simétricas do que as demais cultivares.With the objective of evaluating iceberg lettuce (Lactuca sativa L. cultivars grown under autumn condition, an experience in Santana da Vargem, MG, Brazil, was carried out from March to June of 2002. The experimental design was in randomized complete blocks with thirteen treatments (cultivars Adal, 4553 R7, AEL 10, Iglo, Rocco RZ, Rubette, RX 66, RPT 3030, RPT 2020, Paloma, Sandy, Legacy e Raider and three replicates. The cultivars 45-53R7, RPT 2020, Paloma, Raider and RPT 3030 showed statistically higher total fresh matter than the other cultivars, with the yield ranging 1,010.9; 1,029.4; 1,044.9; 1,075.2 and 1105.2 g plant-1, respectively. The cultivars 45-53R7, RPT 2020, Paloma, Raider, RPT 3030, AEL

  19. Anita: cultivar de alface de verão para cultivo protegido no solo e em hidroponia 'Anita': a new summer lettuce cultivar suitable for protected cultivation in soil and hydroponics systems

    Directory of Open Access Journals (Sweden)

    Ernani Clarete da Silva

    2009-06-01

    Full Text Available 'Anita' é uma cultivar de alface (Lactuca sativa L. do grupo lisa, de cor verde-clara intensa, cujo desenvolvimento se deu a partir de 1994 no município de Campos dos Goytacazes, RJ. Foi selecionada pelo método genealógico a partir do cruzamento entre as cultivares comerciais Vitória e Brasil 303. As plantas contêm diâmetro médio de cabeça de 55 cm, massa fresca de 700 g e número médio de 55 folhas, conforme resultados de ensaios conduzidos nas quatro estações do ano. Possui resistência ao LMV e ao pendoamento precoce em cultivos de verão. As folhas são grandes, macias, crocrantes e adocicadas, sendo estas características mantidas tanto no cultivo protegido no solo quanto em hidroponia.'Anita' is a lettuce cultivar (Lactuca sativa L. of the loose-leaf group whose leaves are of intense green color. This cv. was developed in Campos dos Goytacazes, Rio de Janeiro State, Brazil, since 1994. "Anita" was selected by the pedigree method through crossings between commercial cultivars Vitória and Brasil 303. After evaluations done during four seasons, there were detected a head mean diameter around 55 cm, average fresh plant weight of 700 g and 55 leaves in average. Plants present resistance to Lettuce Mosaic Virus (LMV and high resistance to bolting in the summer. In both cultivation systems, protected environment or hydroponics, plants present leaves of great size, soft and sweet.

  20. Adaptabilidade e estabilidade fenotípica de cultivares de alface do grupo crespa em cultivo hidropônico Adaptability and phenotypic stability of crisp lettuce cultivars in hydroponics

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    Ronan Gualberto

    2009-03-01

    Full Text Available Considerando as diferentes estações climáticas em que a alface é cultivada durante o ano, é de se esperar a ocorrência de uma elevada interação genótipo x ambiente. Em função disto, neste trabalho estudou-se o desempenho produtivo, adaptabilidade e estabilidade fenotípica de seis cultivares de alface do grupo crespa (Deisy, Elba, Sabrina, Summer Green, Vera e Verônica, em sistema hidropônico NFT, instalado em casa-de-vegetação, na Universidade de Marília (SP. Foram conduzidos nove ensaios em três épocas (outono: Out n; inverno: Inv n e; primavera: Pri n, em delineamento inteiramente casualizado, com quatro repetições, avaliando-se quatro plantas por parcela. Ocorreram diferenças significativas entre ambientes (épocas de semeadura. Verificou-se que, de maneira geral, os três plantios realizados no outono apresentaram valores médios de produtividade (Out1 = 3,1; Out2 = 5,3 e; Out3 = 4,6 kg m² superiores aos realizados no inverno (Inv1 = 3,6; Inv2 = 3,5 e; Inv = 3,7 kg m² e primavera (Pri1 = 4,0; Pri2 = 3,6 e; Pri3 = 3,2 kg m². Embora a interação cultivares x ambientes também tenha sido significativa, para produtividade, à exceção dos ambientes Inv3 e Pri1, não ocorreram diferenças significativas entre as cultivares dentro de cada época de plantio e, para número de folhas por planta, ocorreram diferenças significativas entre as cultivares somente no ambiente Out3. As cultivares Deyse e Verônica foram as únicas a mostrarem adaptabilidade a todos ambientes estudados para produtividade; todas as cultivares apresentaram instabilidade para essa mesma característica. Para o número de folhas por planta, somente a cultivar Summer Green apresentou comportamento altamente previsível (estável, no entanto, mostrou-se adaptada somente aos ambientes desfavoráveis.Considering the climatic seasons in which lettuce is cultivated, probably a high interaction genotype x environment could be obtained. The yield

  1. Alterações fenotípicas em cultivares de alface selecionadas para calor Phenotypical alterations in lettuce genotypes selected for heat tolerance

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    José Henrique Conti

    2000-11-01

    Full Text Available Cultivares de alface selecionadas para o pendoamento lento e as mesmas que lhes deram origem foram analisadas quanto a variações morfológicas, com o objetivo de quantificar possíveis modificações adaptativas para as condições de cultivo em épocas de calor. Cultivares dos grupos "manteiga" (Regina, Glória, IAC 303, IAC 202, Sem Rival e Luciana "folha crespa" (Grand Rapids e Brisa e "americana" (Great Lakes e Mesa 659, foram avaliadas em dois plantios de verão, em Piracicaba, em delineamento de blocos casualizados. No primeiro experimento, (novembro/90, foram avaliadas as características de número de estômatos, espessura de folha e quantidade de clorofila total. No segundo, (setembro/91, foram avaliados o peso seco, peso fresco, porcentagem de matéria seca, tempo para pendoamento e número de folhas. As cultivares selecionadas para calor no grupo "manteiga" (Glória e Regina, apresentaram maior número de estômatos (respectivamente 9487/cm² e 7973/cm² e folhas mais grossas (respectivamente 556 mm e 439 mm e também, acumularam maior quantidade de matéria seca (respectivamente 24,55 g e 25,50 g. A cultivar selecionada para calor do grupo "folha crespa" (Brisa acumulou maior quantidade de matéria verde (446,77g e seca (22,40 g, da mesma forma que apresentou maior quantidade de estômatos (7.279/cm². Para as cultivares do grupo "americana", observou-se diferença significativa apenas para espessura de folha, sendo que a cultivar Mesa 659 apresentou folhas mais grossas (589 mm. Constataram-se aumentos significativos da biomassa vegetal nas cultivares selecionadas para calor em relação àquelas não selecionadas. As cultivares que atingiram maior produtividade de matéria seca por planta foram Mesa 659 (28,74 g, Great Lakes (27,17 g e Regina. Os resultados comprovaram que a seleção para o pendoamento lento indiretamente produziu variações adaptativas nas plantas de alface.Lettuce cultivars selected for slow bolting and

  2. Field assessment of the susceptibility of onion cultivars to thrips attack – preliminary results

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    Pobożniak Maria

    2016-03-01

    Full Text Available Field experiments on the susceptibility of onion to thrips infestation were carried out in 2012 and 2013. The investigation used 18 cultivars and 5 breeding lines of Allium cepa, and the species A. fistulosum and A. roylei. In 2012 A. fistulosum was one of the most infested plants, whereas in 2013 infestation was no more than average. The most infested cultivars of A. cepa were ‘Efekt’, ‘Alonso F1’, ‘Alibaba’ and ‘Wama’ and the ‘NOE5’ breeding line. In 2012 the extent of damage ranged from 12 to 55%, in 2013 from 20 to 30%. The ‘NOE2’, ‘NOE3’ and ‘Wama’ cultivars were the most seriously damaged by thrips. Leaf damage to A. fistulosum was minimal. No damage was caused to the wild species A. roylei by feeding onion thrips.

  3. Composição centesimal e teor de nitrato em cinco cultivares de alface produzidas sob cultivo hidropônico Centesimal composition and nitrate content in five cultivars of lettuce produced in hydroponic system

    Directory of Open Access Journals (Sweden)

    Silvana Ohse

    2009-01-01

    Full Text Available Com o objetivo de avaliar a qualidade nutricional de cinco cultivares de alface (Mimosa Verde, Mimosa Vermelha, Vera, Regina e Lucy Brown produzidas em cultivo hidropônico sob sistema NFT, determinou-se sua composição centesimal e seu teor de nitrato. O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições. O experimento foi desenvolvido no Departamento de Engenharia Rural da Universidade Federal de Santa Catarina, Florianópolis (SC, de maio a julho de 2004. As bancadas de produção possuíam sete canais com 6,0 m de comprimento e 1,50 m de largura. O espaçamento utilizado foi 0,25 m e canais e 0,25 m entre plantas no canal. A colheita foi efetuada aos 54 dias após a semeadura, e permanência por 24 dias na bancada de produção. Na cultivar de alface do tipo americana, Lucy Brown, observou-se maior teor de água da parte aérea e também maior teor de nitrato. Nas cultivares Mimosa Vermelha e Mimosa Verde verificaram, em média, maior teor de fitomassa seca da parte aérea, de lipídios, de proteína e maior valor calórico. Na cultivar Mimosa Vermelha constatou-se maior teor de carboidratos e na Mimosa Verde, o maior teor de resíduo mineral, não diferindo da cultivar Regina. O maior teor de fibra foi constatado na cultivar Regina.The nutrition quality of five different lettuce cultivars (Mimosa Verde, Mimosa Vermelha, Vera, Regina and Lucy Brown produced under NFT (Laminar Flow of Solution system was determined by their centesimal composition and nitrate content. To analyze the experimental treatments it was used a completely randomized design with four replications. The experiment was developed in a greenhouse belonging to the Department of Agricultural Engineering of the Federal University of Santa Catarina, Florianópolis, Santa Catarina State, Brazil, from May to July of 2004 (autumn-winter period. The lettuces were grown in a group of benches (3% declivity with seven canals (6.0 m length and 1

  4. Desempenho de cultivares de alface crespa em dois ambientes de cultivo em sistema hidropônico Performance of lettuce cultivars grown in two environments, in the NFT hydroponic system

    Directory of Open Access Journals (Sweden)

    SF Blat

    2011-03-01

    Full Text Available Este trabalho foi desenvolvido em Ribeirão Preto-SP, de 06/02 a 07/04 de 2006. O objetivo foi avaliar o desempenho de cinco cultivares de alface (Pira Roxa, Belíssima, Locarno, Crespona Gigante e Verônica em dois ambientes de cultivo (casa de vegetação climatizada e não climatizada em sistema hidropônico NFT. O delineamento experimental foi em blocos casualizados para cada ambiente com três repetições sendo cinco cultivares. Os ambientes foram comparados por meio de análise conjunta. Avaliaram-se a massa fresca e seca da parte aérea, massas fresca e seca do caule, massa fresca e seca da raiz, número de folhas maiores que 10 cm e número total de folhas. Não houve efeito significativo da interação cultivares e ambientes, demonstrando que as cultivares tiveram comportamento similar em ambos os ambientes.This research was carried out in Ribeirão Preto, São Paulo State, Brazil, from February to April, 2006. The performance of five lettuce cultivars (Pira Roxa, Belíssima, Locarno, Crespona Gigante and Verônica was evaluated, growing the plants in two environments (conventional and acclimatized greenhouse in hydroponic system NFT. A randomized-block experimental design was used for each environment, with three replications and five cultivars. The environments were compared through joint analysis. Evaluations were done for fresh and dry mater of the aboveground part, stem, and roots; number of leaves larger than 10 cm and total number of leaves. The cultivars Crespona Gigante and Verônica were prominent with regard to green and dry mass of the aboveground part, leaves, and roots, as well as to the number of leaves larger than 10 cm. The interaction cultivar x environment was not significant, demonstrating that the cultivars had similar behavior in both environments.

  5. Performance and feeding behaviour of two biotypes of the black currant-lettuce aphid, Nasonovia ribisnigri, on resistant and susceptible Lactuca sativa near-isogenic lines.

    Science.gov (United States)

    ten Broeke, Cindy J M; Dicke, Marcel; van Loon, Joop J A

    2013-10-01

    The black currant-lettuce aphid, Nasonovia ribisnigri, is an important pest of cultivated lettuce, Lactuca sativa. Since 1982, the control of this aphid on lettuce is largely based on host plant resistance, conferred by the Nr gene, introgressed from Lactuca virosa. The resistance mechanism remains to be identified. N. ribisnigri populations virulent on the Nr-based resistance in lettuce have emerged in several locations in Europe since 2007. The objective of this study was to investigate the resistance mechanism mediated by the Nr gene in lettuce by detailed studies of aphid feeding behaviour and performance. Both avirulent (Nr:0) and virulent (Nr:1)biotypes of N. ribisnigri were studied on five resistant and two susceptible near isogenic lines (NILs). In addition, survival and colony development were quantified.Nr:0 aphids showed a strong decrease in sieve element ingestion and took longer to accept a sieve element on resistant NILs compared with susceptible NILs, and no aphids survived on the resistant NIL. Nr:1 aphids fed and performed equally well on the resistant and susceptible NILs. The resistance mechanism against Nr:0 aphids encoded by the Nr gene seems to be located in the phloem, although we also observed differences in feeding behaviour during the pathway phase to the phloem. Nr:1 aphids were highly virulent to the resistance conferred by the Nr gene. The consequences of the appearance of Nr:1 aphids for control of N. ribisnigri are discussed.

  6. Transcriptome analysis of resistant and susceptible alfalfa cultivars infected with root-knot nematode Meloidogyne incognita.

    Directory of Open Access Journals (Sweden)

    Olga A Postnikova

    Full Text Available Nematodes are one of the major limiting factors in alfalfa production. Root-knot nematodes (RKN, Meloidogyne spp. are widely distributed and economically important sedentary endoparasites of agricultural crops and they may inflict significant damage to alfalfa fields. As of today, no studies have been published on global gene expression profiling in alfalfa infected with RKN or any other plant parasitic nematode. Very little information is available about molecular mechanisms that contribute to pathogenesis and defense responses in alfalfa against these pests and specifically against RKN. In this work, we performed root transcriptome analysis of resistant (cv. Moapa 69 and susceptible (cv. Lahontan alfalfa cultivars infected with RKN Meloidogyne incognita, widespread root-knot nematode species and a major pest worldwide. A total of 1,701,622,580 pair-end reads were generated on an Illumina Hi-Seq 2000 platform from the roots of both cultivars and assembled into 45,595 and 47,590 transcripts in cvs Moapa 69 and Lahontan, respectively. Bioinformatic analysis revealed a number of common and unique genes that were differentially expressed in susceptible and resistant lines as a result of nematode infection. Although the susceptible cultivar showed a more pronounced defense response to the infection, feeding sites were successfully established in its roots. Characteristically, basal gene expression levels under normal conditions differed between the two cultivars as well, which may confer advantage to one of the genotypes toward resistance to nematodes. Differentially expressed genes were subsequently assigned to known Gene Ontology categories to predict their functional roles and associated biological processes. Real-time PCR validated expression changes in genes arbitrarily selected for experimental confirmation. Candidate genes that contribute to protection against M. incognita in alfalfa were proposed and alfalfa-nematode interactions with

  7. Cultivar Variation in Hormonal Balance Is a Significant Determinant of Disease Susceptibility to Xanthomonas campestris pv. campestris in Brassica napus

    Directory of Open Access Journals (Sweden)

    Md. Tabibul Islam

    2017-12-01

    Full Text Available This study aimed to directly elucidate cultivar variation in disease susceptibility and disease responses in relation to hormonal status in the interaction of Brassica napus cultivars and Xanthomonas campestris pv. campestris (Xcc, the causal agent of black rot disease. Fully expanded leaves of six B. napus cultivars (cvs. Capitol, Youngsan, Saturnin, Colosse, Tamra, and Mosa were inoculated with Xcc. At 14 days post-inoculation with Xcc, cultivar variation in susceptibility or resistance was interpreted with defense responses as estimated by redox status, defensive metabolites, and expression of phenylpropanoid synthesis-related genes in relation to endogenous hormonal status. Disease susceptibility of six cultivars was distinguished by necrotic lesions in the Xcc-inoculated leaves and characterized concurrently based on the higher increase in reactive oxygen species and lipid peroxidation. Among these cultivars, as the susceptibility was higher, the ratios of abscisic acid (ABA/jasmonic acid (JA and salicylic acid (SA/JA tended to increase with enhanced expression of SA signaling regulatory gene NPR1 and transcriptional factor TGA1 and antagonistic suppression of JA-regulated gene PDF 1.2. In the resistant cultivar (cv. Capitol, accumulation of defensive metabolites with enhanced expression of genes involved in flavonoids (chalcone synthase, proanthocyanidins (anthocyanidin reductase, and hydroxycinnamic acids (ferulate-5-hydroxylase biosynthesis and higher redox status were observed, whereas the opposite results were obtained for susceptible cultivars (cvs. Mosa and Tamra. These results clearly indicate that cultivar variation in susceptibility to infection by Xcc was determined by enhanced alteration of the SA/JA ratio, as a negative regulator of redox status and phenylpropanoid synthesis in the Brasica napus–Xcc pathosystem.

  8. Rhizosphere microbial communities from resistant and susceptible watermelon cultivars showed different response to fusarium oxysporum f. sp. niveum inoculation

    International Nuclear Information System (INIS)

    Zhi, W.F.; Can, C.S.; Ling, C.; Hui, X.W.

    2015-01-01

    Fusarium oxysporum f. sp. niveum (FON), a soil-borne pathogen of watermelon (Citrullus lanatus), can cause substantial production losses worldwide. In this study, plate culture and PCR-denaturing gradient gel electrophoresis (DGGE) methods were used to evaluate the effects of inoculation of Fusarium oxysporum f.sp. niveum on rhizosphere microbial communities of different watermelon cultivars to FON. Two methods indicated that the effects of watermelon rhizosphere microbial community of different resistance cultivars to FON were much different. Populations of culturable bacteria and actinomycetes in the rhizosphere of susceptible watermelon cultivar were significantly lower than in the resistant cultivar after inoculation (P<0.05), but the opposite result was observed for fungi. Principal component analysis of bacterial and fungal community structure also showed that the cultivar of FON-inoculated soil treatment were separated from the non-inoculated controls after inoculation, and there was clear discrimination between the susceptible cultivars and the resistant cultivars. Sequence analysis of specific bands from DGGE profiles showed that specific rhizosphere bacterial and fungal groups differed between watermelon cultivars after inoculation . Both methods demonstrated that different resistant watermelon cultivars occupied different rhizosphere microbial communities, and and disease suppression might be correlated with high microbial diversity. F. oxysporum f. sp. Niveum alters the structure and functional diversity of microbial communities associated with watermelon rhizosphere. (author)

  9. Interação genótipo x ambiente em cultivares de alface na região de Jaboticabal Interaction genotype x environment of lettuce cultivars in Jaboticabal, Brazil

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    Eduardo B. de Figueiredo

    2004-03-01

    Full Text Available Estudou-se a interação genótipo x ambiente de doze cultivares de alface, sendo quatro do grupo lisa (Babá de Verão, Karla, Nacional e Elisa, quatro do grupo crespa (Simpson, Hortência, Verônica e Grand Rapids e quatro do grupo americana (Laidy, Tainá, Lucy Brown e Raider. Os tratamentos foram constituídos pelo cultivo da alface em dez ambientes (casa de vegetação, túnel baixo de cultivo, túnel baixo com sombrite, agrotêxtil e campo, na presença e ausência de mulching. Foram utilizados dois períodos de cultivo, agosto a novembro de 2001 e março a junho de 2002 em Jaboticabal. Cada experimento (ambiente de cultivo foi conduzido utilizando-se o delineamento de blocos casualizados, com doze cultivares e três repetições. A análise de variância conjunta demonstrou valores de F significativos (pWe evaluated the interaction genotype x environment of twelve genotypes of lettuce (Babá de Verão, Karla, Nacional, Elisa, Simpson, Hortência, Verônica, Grand Rapids, Laidy, Tainá, Lucy Brown and Raider, cultivated under greenhouse, low tunnel, low tunnel covered with black plastic screen, floating row cover (light-weight woven and open field. All these treatments were conducted with and without mulching with ten treatments in total. The experiments were conducted in two different periods (August to November, 2001 and March to June, 2002. Each experiment (growth environment was conducted using randomized blocks and three replicates. The measured variables were dry matter, volume and number of leaves. The value of F was significant (p<0,01 for the interaction genotype x environment. For the planting period from August to November/2001, the best results were obtained with the butterhead cultivars (Babá de Verão, Karla, Nacional, Elisa, cultivated under greenhouse with mulching, low tunnel without mulching and field without mulching. All cultivars had the worst performance when cultivated under tunnel with black plastic screen with or

  10. Evaluation of indicators to determine black sigatoka susceptibility in five banana hybrid cultivars ( Mycosphaerella fijiensis Morelet

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    Reinaldo Pérez Armas

    2014-10-01

    Full Text Available This work had the objective of determining the variation of growth, development and yields indicators of five banana hybrid cultivars. The research was carried in the Agroindustrial Farm Marta Abreu, Cienfuegos, in a carbonated Brown soil. It was made a characterization of the soil and the climatic variables. A field experiment was developed with a design in blocks at random with four repetitions with five banana cultivars as treatments (‘FHIA-18’, ‘FHIA-02’, ‘FHIA-01’, ‘SH-3436 L-9’ and ‘FHIA-23’ . The plots had an area of 56 m2 with 16 plants, been evaluated eight for a total 32 plants for cultivar. The variable evaluated were the spotty youngest leaf, number of leaf by plant, incubation time (PI, evolution time of symptoms (TES and developing time of symptoms (TED, severity index (IS, active photosynthetic index (INHE and infection relative index. The cultivars FHIA-23 and SH 3436 L9 presented a hither time of development of the disease. In a general the more susceptible cultivar to the black Sigatoka under of the farm condition was FHIA-23. The clones FHIA-18, FHIA-01 and FHIA-02 presented the best behavior in the spotted youngest leaf and the number of leaf up to the flowering and the harvest time. The clones FHIA-01 and FHIA-18 have the better response to Black Sigatoka attending to the incubation period, the evolution time of the symptom and develo pment time of the disease

  11. A model for multiseasonal spread of verticillium wilt of lettuce.

    Science.gov (United States)

    Wu, B M; Subbarao, K V

    2014-09-01

    Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

  12. Evaluation of Lettuce Genotypes for Seed Thermotolerance

    Science.gov (United States)

    Thermoinhibition of lettuce (Lactuca sativa L.) seed germination is a common problem associated with lettuce production. Depending on lettuce cultivars, seed germination may be inhibited when temperatures exceed 28oC. The delay or inhibition of seed germination at high temperatures may reduce seedli...

  13. Cultivars

    Directory of Open Access Journals (Sweden)

    Oleg Blum

    2011-01-01

    Full Text Available Some modern agrochemicals with antioxidant potential were tested for their protective effect against ozone injury using clover and tobacco ozone-sensitive cultivars as model plants subjected to ambient ozone at two sites (Kyiv city in Ukraine and Szarów village in Poland. All used agrochemicals showed partial protective effects against ozone injury on clover and tobacco. Conducted studies confirmed the effectiveness of modern fungicides belonging to strobilurin group as protectants of sensitive crops against ozone damage. The effectiveness of new growth regulators “Emistym C” and “Agrostymulin” was showed for the first time. Out of the studied agrochemicals, fungicide “Strobi” and natural growth regulator “Emistym C” demonstrated the best protective effects. These agrochemicals present promise for further studies of their possible utilization for enhancement of ozone tolerance of sensitive crops.

  14. Feeding behaviour and performance of different populations of the black currant-lettuce aphid, Nasonovia ribisnigri, on resistant and susceptible lettuce

    NARCIS (Netherlands)

    Broeke, ten C.J.M.; Dicke, M.; Loon, van J.J.A.

    2013-01-01

    When crops are bred for resistance to herbivores, these herbivores are under strong selection pressure to overcome this resistance, which may result in the emergence of virulent biotypes. This is a growing problem for crop species attacked by aphids. The Nr-gene in lettuce confers near-complete

  15. LC-MS Untargeted Metabolomics To Explain the Signal Metabolites Inducing Browning in Fresh-Cut Lettuce.

    Science.gov (United States)

    García, Carlos J; García-Villalba, Rocío; Gil, María I; Tomas-Barberan, Francisco A

    2017-06-07

    Enzymatic browning is one of the main causes of quality loss in lettuce as a prepared and ready-to-eat cut salad. An untargeted metabolomics approach using UPLC-ESI-QTOF-MS was performed to explain the wound response of lettuce after cutting and to identify the metabolites responsible of browning. Two cultivars of Romaine lettuce with different browning susceptibilities were studied at short time intervals after cutting. From the total 5975 entities obtained from the raw data after alignment, filtration reduced the number of features to 2959, and the statistical analysis found that only 1132 entities were significantly different. Principal component analysis (PCA) clearly showed that these samples grouped according to cultivar and time after cutting. From those, only 15 metabolites belonging to lysophospholipids, oxylipin/jasmonate metabolites, and phenolic compounds were able to explain the browning process. These selected metabolites showed different trends after cutting; some decreased rapidly, others increased but decreased thereafter, whereas others increased during the whole period of storage. In general, the fast-browning cultivar showed a faster wound response and a higher raw intensity of some key metabolites than the slow-browning one. Just after cutting, the fast-browning cultivar contained 11 of the 15 browning-associated metabolites, whereas the slow-browning cultivar only had 5 of them. These metabolites could be used as biomarkers in breeding programs for the selection of lettuce cultivars with lower browning potential for fresh-cut applications.

  16. Analysis of early events in the interaction between Fusarium graminearum and the susceptible barley (Hordeum vulgare) cultivar Scarlett

    DEFF Research Database (Denmark)

    Yang, Fen; Jensen, J.D.; Svensson, Birte

    2010-01-01

    A proteomic analysis was conducted to map the events during the initial stages of the interaction between the fungal pathogen Fusarium graminearum and the susceptible barley cultivar Scarlett. Quantification of fungal DNA demonstrated a sharp increase in fungal biomass in barley spikelets at 3 da...

  17. Assessing genetic variation in lettuce for traits related to nitrogen use efficiency using susceptibility and relative efficiency indices

    Science.gov (United States)

    Lettuce is a high value commodity in the USA with annual value of ~$2.5 billion. California produces ~75 percent of all lettuce in the country. Overuse of agricultural inputs for crop production can cause detrimental effects to the health of Californians as well as on agricultural and natural resour...

  18. Feeding behavior and performance of Nasonovia ribisnigri on grafts, detached leaves, and leaf disks of resistant and susceptible lettuce

    NARCIS (Netherlands)

    Broeke, ten Cindy J.M.; Dicke, Marcel; Loon, van Joop J.A.

    2016-01-01

    Aphids are dependent on the phloem sap of plants as their only source of nutrients. Host-plant resistance in lettuce, Lactuca sativa L. (Asteraceae), mediated by the Nr gene is used to control the lettuce aphid Nasonovia ribisnigri (Mosely) (Hemiptera: Aphididae). The resistance is located in the

  19. Lettuce and spinach breeding

    Science.gov (United States)

    Lettuce and spinach production is beset by numerous biotic an abiotic challenges, thus the leafy-vegetable industry of California requires continued development of improved, adapted cultivars to meet new disease and insect problems, changes in the market, and changes in growing procedures. The lettu...

  20. Bacterial networks and co-occurrence relationships in the lettuce root microbiota.

    Science.gov (United States)

    Cardinale, Massimiliano; Grube, Martin; Erlacher, Armin; Quehenberger, Julian; Berg, Gabriele

    2015-01-01

    Lettuce is one of the most common raw foods worldwide, but occasionally also involved in pathogen outbreaks. To understand the correlative structure of the bacterial community as a network, we studied root microbiota of eight ancient and modern Lactuca sativa cultivars and the wild ancestor Lactuca serriola by pyrosequencing of 16S rRNA gene amplicon libraries. The lettuce microbiota was dominated by Proteobacteria and Bacteriodetes, as well as abundant Chloroflexi and Actinobacteria. Cultivar specificity comprised 12.5% of the species. Diversity indices were not different between lettuce cultivar groups but higher than in L. serriola, suggesting that domestication lead to bacterial diversification in lettuce root system. Spearman correlations between operational taxonomic units (OTUs) showed that co-occurrence prevailed over co-exclusion, and complementary fluorescence in situ hybridization-confocal laser scanning microscopy (FISH-CLSM) analyses revealed that this pattern results from both potential interactions and habitat sharing. Predominant taxa, such as Pseudomonas, Flavobacterium and Sphingomonadaceae rather suggested interactions, even though these are not necessarily part of significant modules in the co-occurrence networks. Without any need for complex interactions, single organisms are able to invade into this microbial network and to colonize lettuce plants, a fact that can influence the susceptibility to pathogens. The approach to combine co-occurrence analysis and FISH-CLSM allows reliably reconstructing and interpreting microbial interaction networks. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Resposta de cultivares de alface à salinidade da solução nutritiva com rejeito salino em hidroponia Response of lettuce cultivars to nutrient solution salinity with saline rejects in hydropony

    Directory of Open Access Journals (Sweden)

    Nildo da S Dias

    2011-10-01

    Full Text Available No processo de dessalinização se gera, além da água potável, um rejeito altamente salino e de poder poluente elevado, o qual pode ser utilizado na produção agrícola rentável dependendo da adoção de práticas culturais adequadas e da tolerância das plantas às condições salinas. Nos últimos anos a tendência tem sido a substituição da agricultura convencional por sistemas hidropônicos de cultivos, considerados um dos mais eficientes no uso de água. O objetivo desta pesquisa foi analisar a resposta de duas cultivares de alface sob sistema hidropônico de cultivo (Lactuca sativa L., cvs. Verônica e Babá de verão em diferentes níveis de salinidade da solução nutritiva preparadas com água de abastecimento, água de rejeito coletada no dessalinizador e da sua diluição com água de abastecimento a 75, 50 e 25%, resultando em condutividades elétricas da solução nutritiva (CEs de 1,1; 2,4; 3,6; 4,7 e 5,7 dS m-1 após as diluições e adição de fertilizantes. Ocorreu variação genotípica sob as variáveis de crescimento e produção da alface, exceto para o número de folhas, sendo a cultivar Babá de verão a que produziu maior rendimento, independentemente do nível de salinidade e, portanto, a cultivar mais tolerante à salinidade da água com rejeito salino.In desalination process, besides the potable water, highly salty and polluted water (brine is generated, which can be used for producing profitable crops depending on the adequate cultural practices as well as on the plant ability of reacting to saline conditions. The trend in recent years has been towards conversion of conventional agriculture to soilless agriculture which is considered to be a more efficient use of water system. The aim of this research was to examine the response of two lettuce cultivars (Lactuca sativa L. cvs. Veronica, Babá de verão under hydroponic system to different levels of salinity of the nutrient solutions prepared with tap water

  2. Advancements in utilizing molecular markers in lettuce breeding

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is globally the most popular commercially produced, leafy vegetable, farmed in moderate climates. Cultivated lettuce is a self-fertilizing, diploid (2n = 2x = 18) species from the family Compositae (Asteraceae). New cultivars of lettuce are developed by combining desirabl...

  3. Determination of proteins induced in response to jasmonic acid and salicylic acid in resistant and susceptible cultivars of tomato.

    Science.gov (United States)

    Afroz, Amber; Khan, Muhammad Rashid; Komatsu, Setsuko

    2010-07-01

    Jasmonic acid (JA) and salicylic acid (SA) are signaling molecules that play key roles in the regulation of metabolic processes, reproduction, and defense against pathogens. The proteomics approach was used to identify proteins that are induced by JA and SA in the tomato cultivars Roma and Pant Bahr, which are susceptible and resistant to bacterial wilt, respectively. Threonine deaminase and leucine amino peptidase were upregulated, and ribulose-1,5-bisphosphate carboxylase/oxygenase small chain was downregulated by time-course application of JA. Translationally controlled tumor protein was upregulated by time-course application of SA. Protein disulfide isomerase was upregulated by application of either JA or SA. Proteins related to defense, energy, and protein destination/storage are suspected to be responsible for the susceptibility or resistance of the cultivars. Furthermore, in Roma, iron ABC transporter was upregulated by JA and down-regulated by SA. Iron ABC transporter plays a part in the signal transduction of both JA and SA in cultivars of tomato that are resistant to bacterial wilt.

  4. Lettuce breeding

    Science.gov (United States)

    In the 2016-2017 period, major efforts targeted resistance to lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium wilt, bacterial leaf spot, corky root, downy mildew, drought tolerance, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Resi...

  5. Profiling dehydrin gene sequence and physiological parameters in drought tolerant and susceptible spring wheat cultivars

    International Nuclear Information System (INIS)

    Baloch, M.J.; Jatoi, W.A.

    2012-01-01

    Physiological and yield traits such as stomatal conductance (mmol m-/sup 2/s/sup -1/), Leaf relative water content (RWC %) and grain yield per plant were studied in a separate experiment. Results revealed that five out of sixteen cultivars viz. Anmol, Moomal, Sarsabz, Bhitai and Pavan, appeared to be relatively more drought tolerant. Based on morphophysiological results, studies were continued to look at these cultivars for drought tolerance at molecular level. Initially, four well recognized primers for dehydrin genes (DHNs) responsible for drought induction in T. durum L., T. aestivum L. and O. sativa L. were used for profiling gene sequence of sixteen wheat cultivars. The primers amplified the DHN genes variably like Primer WDHN13 (T. aestivum L.) amplified the DHN gene in only seven cultivars whereas primer TdDHN15 ( T. durum L.) amplified all the sixteen cultivars with even different DNA banding patterns some showing second weaker DNA bands. Third primer TdDHN16 (T. durum L.) has shown entirely different PCR amplification prototype, specially showing two strong DNA bands while fourth primer RAB16C (O. sativa L.) failed to amplify DHN gene in any of the cultivars. Examination of DNA sequences revealed several interesting features. First, it identified the two exon/one intron structure of this gene (complete sequences were not shown), a feature not previously described in the two database cDNA sequences available from T. aestivum L. (gi|21850). Secondly, the analysis identified several single nucleotide polymorphisms (SNPs), positions in gene sequence. Although complete gene sequence was not obtained for all the cultivars, yet there were a total of 38 variable positions in exonic (coding region) sequence, from a total gene length of 453 nucleotides. Matrix of SNP shows these 37 positions with individual sequence at positions given for each of the 14 cultivars (sequence of two cultivars was not obtained) included in this analysis. It demonstrated a considerab le

  6. Evaluation of Lettuce Germplasm Resistance to Gray Mold Disease for Organic Cultivations

    Directory of Open Access Journals (Sweden)

    Chang Ki Shim

    2014-03-01

    Full Text Available This study was conducted to evaluate the resistance of 212 accessions of lettuce germplasm to gray mold disease caused by Botrytis cinerea. The lettuce germplasm were composed of five species: Lactuca sativa (193 accessions, L. sativa var. longifolia (2 accessions, L. sativa var. crispa (2 accessions, L. saligna (2 accessions, and L. serriola (1 accession; majority of these originated from Korea, Netherlands, USA, Russia, and Bulgaria. After 35 days of spray inoculation with conidial suspension (3×10⁷ conidia/ml of B. cinerea on the surface of lettuce leaves, tested lettuce germplasm showed severe symptoms of gray mold disease. There were 208 susceptible accessions to B. cinerea counted with 100% of disease incidence and four resistant accessions, IT908801, K000598, K000599, and K021055. Two moderately resistant accessions of L. sativa, K021055 and IT908801, showed 20% of disease incidence of gray mold disease at 45 days after inoculation; and two accessions of L. saligna, K000598 and K000599, which are wild relatives of lettuce germplasm with loose-leaf type, showed complete resistance to B. cinerea. These four accessions are candidates for breeding lettuce cultivars resistant to gray mold disease.

  7. Desempenho de cultivares de alface em cultivo hidropônico sob dois níveis de condutividade elétrica Evaluation of two electric conductivity levels on the hidroponic cultivation of lettuce

    Directory of Open Access Journals (Sweden)

    Adriana G Magalhães

    2010-09-01

    Full Text Available O objetivo do trabalho foi comparar cultivares de alface de folhas soltas lisas, submetidas a estresse osmótico em soluções nutritivas sob cultivo hidropônico. Foram realizados dois experimentos, cada um com uma condutividade elétrica (C.E. de 2,0 dS m-1 e 2,5 dS m-1. Os tratamentos foram as cultivares de alface Babá de Verão, Floresta, Luisa, Manoa, Regina 579, Saia Véia e Vitória Verdinha. O delineamento experimental foi blocos casualizados, com três repetições. A colheita foi feita aos 45 dias após a semeadura. Nenhuma cultivar se destacou no conjunto das características avaliadas, embora a Manoa tenha apresentado o maior índice de queima de bordas das folhas, sem diferir estatisticamente da Saia Véia e Babá de Verão. As cultivares Regina 579 e Vitória Verdinha são as preferidas dos produtores hidropônico de Pernambuco, devido à falta de genótipos mais adaptados a essa modalidade de cultivo, e por apresentarem folhas lisas, levemente enrugadas e de textura macia.The aim of this work was to compare loose-leaf lettuce cultivars submitted to osmotic stress in nutrient solutions in hydroponic culture. Two experiments were carried out, with electric conductivity of 2.0 or 2.5 dS m-1. The treatments were the cultivars Babá de Verão, Floresta, Luisa, Manoa, Regina 579, Saia Véia, and Vitória Verdinha. The experimental design was randomized blocks with three replications. Harvest was performed 45 days after sowing. None among the cultivars differed clearly on the characteristics evaluated. However, "Manoa" showed the highest rate of leaf-edge burning, without significant difference in comparison to "Saia Véia" and "Babá de Verão" for summer. The cultivars Regina 579 and Vitória Verdinha are preferred by the growers of hydroponic vegetables of Pernambuco, due to the lack of better genotypes for this type of cultivation and due to the presence of smooth slightly-wrinkled leaves with soft texture.

  8. Relative resistance or susceptibility of maple (Acer) species, hybrids and cultivars to six arthropod pests of production nurseries.

    Science.gov (United States)

    Seagraves, Bonny L; Redmond, Carl T; Potter, Daniel A

    2013-01-01

    Maples (Acer spp.) in production nurseries are vulnerable to numerous arthropod pests that can stunt or even kill the young trees. Seventeen cultivars representing various Acer species and hybrids were evaluated for extent of infestation or injury by shoot and trunk borers (Proteoteras aesculana, Chrysobothris femorata), potato leafhopper (Empoasca fabae), Japanese beetle (Popillia japonica), maple spider mite (Oligonychus aceris) and calico scale (Eulecanium cerasorum). Evaluations were done in replicated field plots in central and western Kentucky. All of the maples were susceptible, to varying degrees, to one or more key pest(s). Red maples (A. rubrum) were relatively vulnerable to potato leafhopper injury and borers but nearly free of Japanese beetle feeding and spider mites. Sugar maples sustained conspicuous Japanese beetle damage but had very low mite populations, whereas the opposite was true for Freeman maples (A. × freemanii). A. campestre was heavily infested by calico scale. Within each species or hybrid there were cultivar differences in degree of infestation or damage by particular pests. The results should help growers to focus pest management efforts on those plantings at greatest risk from particular pests, and to choose cultivars requiring fewer insecticide inputs to produce a quality tree. Copyright © 2012 Society of Chemical Industry.

  9. Growth and photosynthesis of lettuce

    NARCIS (Netherlands)

    Holsteijn, van H.M.C.

    1981-01-01

    Butterhead lettuce is an important glass-house crop in the poor light period in The Netherlands. Fundamental data about the influence of temperature, light and CO 2 on growth and photosynthesis are important e.g. to facilitate selection criteria for new cultivars. In

  10. Fungal polygalacturonase activity reflects susceptibility of carnation cultivars to Fusarium wilt

    NARCIS (Netherlands)

    Baayen, R.P.; Schoffelmeer, E.A.M.; Toet, S.; Elgersma, D.M.

    1997-01-01

    Carnation cultivars with different levels of partial resistance were inoculated with race 2 of Fusarium oxysporum f.sp. dianthi and monitored for accumulation of host phytoalexins, fungal escape from compartmentalization, production of fungal pectin-degrading enzymes and development of external

  11. Starch Hydrolysis and Vessel Occlusion Related to Wilt Symptoms in Olive Stems of Susceptible Cultivars Infected by Verticillium dahliae

    Science.gov (United States)

    Trapero, Carlos; Alcántara, Esteban; Jiménez, Jaime; Amaro-Ventura, María C.; Romero, Joaquín; Koopmann, Birger; Karlovsky, Petr; von Tiedemann, Andreas; Pérez-Rodríguez, Mario; López-Escudero, Francisco J.

    2018-01-01

    This study investigated starch content, amount of pathogen DNA and density of occluded vessels in healthy and Verticillium dahliae infected olive shoots and stems. Starch hydrolysis is considered a mechanism to refill xylem vessels that suffered cavitation by either, drought conditions or pathogen infections. The main objective of this work was to evaluate this mechanism in olive plants subjected to V. dahliae infection or to drought conditions, in order to know the importance of cavitation in the development of wilting symptoms. In initial experiments starch content in the shoots was studied in trees of cultivars differing in the level of resistance growing in fields naturally infested with V. dahliae. The starch content, esteemed by microscopic observation of stem transversal sections stained with lugol, decreased with the level of symptom severity. Results were confirmed in a new experiment developed with young plants of cultivars ‘Picual’ (highly susceptible), ‘Arbequina’ (moderately susceptible) and ‘Frantoio’ (resistant), growing in pots under greenhouse conditions, either inoculated or not with V. dahliae. In this experiment, the pathogen DNA content, quantified by real-time PCR, and the density of occluded vessels, recorded by microscopic observations of transversal sections stained with toluidine blue, were related to the symptoms severity caused by the pathogen. Finally, a drought experiment was established with young plants of the cultivar ‘Picual’ grown in pots under greenhouse conditions in order to compare the effects caused by water deficit with those caused by the pathogen infection. In both cases, results show that starch hydrolysis occurred, what indirectly evidence the importance of xylem cavitation in the development of the symptoms caused by V. dahliae but in the water stressed plants no vessel occlusion was detected. PMID:29445388

  12. Starch Hydrolysis and Vessel Occlusion Related to Wilt Symptoms in Olive Stems of Susceptible Cultivars Infected by Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Carlos Trapero

    2018-01-01

    Full Text Available This study investigated starch content, amount of pathogen DNA and density of occluded vessels in healthy and Verticillium dahliae infected olive shoots and stems. Starch hydrolysis is considered a mechanism to refill xylem vessels that suffered cavitation by either, drought conditions or pathogen infections. The main objective of this work was to evaluate this mechanism in olive plants subjected to V. dahliae infection or to drought conditions, in order to know the importance of cavitation in the development of wilting symptoms. In initial experiments starch content in the shoots was studied in trees of cultivars differing in the level of resistance growing in fields naturally infested with V. dahliae. The starch content, esteemed by microscopic observation of stem transversal sections stained with lugol, decreased with the level of symptom severity. Results were confirmed in a new experiment developed with young plants of cultivars ‘Picual’ (highly susceptible, ‘Arbequina’ (moderately susceptible and ‘Frantoio’ (resistant, growing in pots under greenhouse conditions, either inoculated or not with V. dahliae. In this experiment, the pathogen DNA content, quantified by real-time PCR, and the density of occluded vessels, recorded by microscopic observations of transversal sections stained with toluidine blue, were related to the symptoms severity caused by the pathogen. Finally, a drought experiment was established with young plants of the cultivar ‘Picual’ grown in pots under greenhouse conditions in order to compare the effects caused by water deficit with those caused by the pathogen infection. In both cases, results show that starch hydrolysis occurred, what indirectly evidence the importance of xylem cavitation in the development of the symptoms caused by V. dahliae but in the water stressed plants no vessel occlusion was detected.

  13. Performance and feeding behaviour of two biotypes of the black currant-lettuce aphid, Nasonovia ribisnigri, on resistant and susceptible Lactuca sativa near-isogenic lines

    NARCIS (Netherlands)

    Broeke, ten C.J.M.; Dicke, M.; Loon, van J.J.A.

    2013-01-01

    The black currant-lettuce aphid, Nasonovia ribisnigri, is an important pest of cultivated lettuce, Lactuca sativa. Since 1982, the control of this aphid on lettuce is largely based on host plant resistance, conferred by the Nr gene, introgressed from Lactuca virosa. The resistance mechanism remains

  14. Use of Simple Sequence Repeat (SSR) markers for DNA fingerprinting and diversity analysis of sugarcane (Saccharum spp.) cultivars resistant and susceptible to red rot

    Science.gov (United States)

    In recent years SSR markers have been used widely for the genetic analysis. The objective of present research was to use SSR markers to develop DNA-based genetic identification and analyze genetic relationship of sugarcane cultivars grown in Pakistan either resistant or susceptible to red rot. Twent...

  15. Detailed characterization of Mirafiori lettuce virus-resistant transgenic lettuce.

    Science.gov (United States)

    Kawazu, Yoichi; Fujiyama, Ryoi; Noguchi, Yuji; Kubota, Masaharu; Ito, Hidekazu; Fukuoka, Hiroyuki

    2010-04-01

    Lettuce big-vein disease is caused by Mirafiori lettuce virus (MiLV), which is vectored by the soil-borne fungus Olpidium brassicae. A MiLV-resistant transgenic lettuce line was developed through introducing inverted repeats of the MiLV coat protein (CP) gene. Here, a detailed characterization study of this lettuce line was conducted by comparing it with the parental, non-transformed 'Kaiser' cultivar. There were no significant differences between transgenic and non-transgenic lettuce in terms of pollen fertility, pollen dispersal, seed production, seed dispersal, dormancy, germination, growth of seedlings under low or high temperature, chromatographic patterns of leaf extracts, or effects of lettuce on the growth of broccoli or soil microflora. A significant difference in pollen size was noted, but the difference was small. The length of the cotyledons of the transgenic lettuce was shorter than that of 'Kaiser,' but there were no differences in other morphological characteristics. Agrobacterium tumefaciens used for the production of transgenic lettuce was not detected in transgenic seeds. The transgenic T(3), T(4), and T(5) generations showed higher resistance to MiLV and big-vein symptoms expression than the resistant 'Pacific' cultivar, indicating that high resistance to lettuce big-vein disease is stably inherited. PCR analysis showed that segregation of the CP gene was nearly 3:1 in the T(1) and T(2) generations, and that the transgenic T(3) generation was homozygous for the CP gene. Segregation of the neomycin phosphotransferase II (npt II) gene was about 3:1 in the T(1) generation, but the full length npt II gene was not detected in the T(2) or T(3) generation. The segregation pattern of the CP and npt II genes in the T(1) generation showed the expected 9:3:3:1 ratio. These results suggest that the fragment including the CP gene and that including the npt II gene have been integrated into two unlinked loci, and that the T(1) plant selected in our study did

  16. Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy).

    Science.gov (United States)

    Iannotta, Nino; Noce, Maria E; Ripa, Vincenzo; Scalercio, Stefano; Vizzarri, Veronica

    2007-01-01

    Within the framework of research concerning the application of techniques alternative to chemical pesticides for control of parasites, the C.R.A. Experimental Institute for Olive Growing for many years has been performing a large investigation in order to detect sources of genetic resistance in olive germplasm. In the present study we observed the behavior related to the olive fly (Bactrocera oleae) infestation and Camarosporium dalmaticum infection of ten olive cultivars farmed under the same agronomic and climatic conditions in Calabria, Southern Italy. The sampling and the data collecting were carried out in three different ripening times. The drupe amount of oleuropein and cyanidine was detected by laboratory analyses in order to verify a possible correlation between these molecules and the level of infestation/infection of the above-mentioned parasites. The obtained data were submitted to analysis of variance. In relation to the fungal infection the results displayed that cvs Tonda nera dolce showed the lowest susceptibility, while the cv Giarraffa turned out to be the most susceptible. The less susceptible cultivars to the phytophagous were Tonda nera dolce and Bhardi Tirana. Since the less susceptible cultivar to olive fly attacks are the same observed in relation to the susceptibility to olive fruit rot, it is suggested a relation between the olive fly infestation and the fungal infection. It suggests the utility to achieve these results both to transfer directly to the farmers' world and to emphasize ecosystem health and biodiversity conservation.

  17. Metabolite profiles of rice cultivars containing bacterial blight-resistant genes are distinctive from susceptible rice

    Institute of Scientific and Technical Information of China (English)

    Jiao Wu; Haichuan Yu; Haofu Dai; Wenli Mei; Xin Huang; Shuifang Zhu; Ming Peng

    2012-01-01

    The metabolic changes of bacterial blight-resistant line C418/Xa23 generated by molecular marker-assisted selection (n =12),transgenic variety C418-Xa21 generated by using the Agrobacterium-mediated system (n =12),and progenitor cultivar C418 (n =12) were monitored using gas chromatography/mass spectrometry.The validation,discrimination,and establishment of correlative relationships between metabolite signals were performed by cluster analysis,principal component analysis,and partial least squares-discriminant analysis.Significant and unintended changes were observed in 154 components in C418/Xa23 and 48 components in C418-Xa21 compared with C418 (P < 0.05,Fold change > 2.0).The most significant decreases detected (P< 0.001) in both C418/Xa23 and C418-Xa21 were in three amino acids: glycine,tyrosine,and alanine,and four identified metabolites: malic acid,ferulic acid,succinic acid,and glycerol.Linoleic acid was increased specifically in C418/Xa23 which was derived from traditional breeding.This line,possessing a distinctive metabolite profile as a positive control,shows more differences vs.the parental than the transgenic line.Only succinic acid that falls outside the boundaries of natural variability between the two non-transgenic varieties C418 and C418/Xa23 should be further investigated with respect to safety or nutritional impact.

  18. Influence of production time on quality and height of yield of crisp lettuce

    International Nuclear Information System (INIS)

    Odziemkowski, S.; Gajc-Wolska, J.; Skapski, H.

    1998-01-01

    The cultivar of crisp lettuce Saladin, was grown in the field in 10 production terms starting from spring to autumn in 1993-95. The highest average weight of head of crisp lettuce was obtained in earlier terms of production. The head weight at the time of harvest depended on the amount of solar radiation during the time of lettuce head formation

  19. Marker-assisted selection for disease resistance in lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is the most popular leafy vegetable that is cultivated mainly in moderate climate. Consumers demand lettuce with good visual appearance and free of disease. Improved disease resistance of new cultivars is achieved by combining desirable genes (or alleles) from existing cu...

  20. Suscetibilidade de biótipos de arroz-vermelho e de cultivares de arroz irrigado ao herbicida imazethapyr Susceptibility of red rice biotypes and commercial rice cultivars to imazethapyr

    Directory of Open Access Journals (Sweden)

    S.H.B. Dornelles

    2010-01-01

    Full Text Available Para avaliar a suscetibilidade de biótipos de arroz-vermelho(Oryza sativa e cultivares comerciais de arroz ao herbicida imazethapyr, realizou-se um ensaio em casa de vegetação com cinco biótipos de arroz-vermelho (acessos Santa Maria 5, Pelotas 3, Rio Pardo 1, Manoel Viana 2 e Catuçaba 1, dois cultivares comerciais de arroz: Clearfield® (IRGA 422 CL e Puitá INTA CL e um cultivar convencional (IRGA 417. Utilizou-se a metodologia de curvas de dose-resposta proposta por Seefeldt et al. (1995. A metodologia de curvas de resposta foi gerada a partir dos parâmetros do modelo logístico e dos valores de I50. Os biótipos de arroz-vermelho e os cultivares foram submetidos a seis doses do herbicida imazethapyr (0; 33,12; 66,25; 132,5; 265,0; e 530,0 g i.a. ha-1. As plantas de arroz foram contadas e coletadas no 20º dia após a aplicação dos tratamentos. A análise do percentual de dano foi realizada através de avaliação visual da fitointoxicação (%, massa verde e massa seca das plantas. Analisando as curvas e os resultados da análise da variância, pode-se inferir que os cultivares Clearfield Irga 422 CL e Puitá INTA CL foram significativamente iguais ao biótipo de arroz-vermelho Catuçaba 1, resistindo a doses de imazethapyr superiores à recomendada em campo para o sistema Clearfield®. Os biótipos Manoel Viana 2, Santa Maria 5 e Pelotas 3 agruparam-se com o cultivar convencional IRGA 417, sendo suscetíveis à dose comercial do herbicida. O biótipo Rio Pardo 1 também é resistente ao herbicida imazethapyr, porém menos resistente que o biótipo Catuçaba 1.To evaluate the susceptibility of biotypes of red rice (Oryza sativa and commercial rice cultivars to the herbicide imazethapyr, a greenhouse assay was conducted with five red rice biotypes (accesses Santa Maria 5, Pelotas 3, Rio Pardo 1, 2 and Manoel Viana Catuçaba 1, two commercial rice cultivars: Clearfield ® (Irga CL 422 and CL Puit INTA, and a conventional cultivar (Irga

  1. Exploring the Limits of Crop Productivity: High Light Studies with Lettuce

    OpenAIRE

    USU Crop Physiology Lab

    2015-01-01

    There are many different leaf lettuce cultivars and they range in color from light green and yellow to deep green as a result of higher concentrations of chlorophyll in the leaves. We tested four cultivars in high light to explore the limits of lettuce productivity.

  2. Effect of Drought Stress on Antioxidant Enzymes and Cell Death Related Traits in Resistant and Susceptible Wheat Cultivars at Grain Filling Stage

    Directory of Open Access Journals (Sweden)

    H. Hasheminasab

    2013-10-01

    Full Text Available Drought is one of the major factors limiting crop production in Iran. Twenty Iranian wheat cultivars with wide range of sensitivity to drought, including 18 varieties of bread wheat and two varieties of durum wheat were used in two separate field experiments in 2009-2010 at the Experimental Station of College of Agricultural in Shiraz University. Each experiment was conducted as a randomized complete block design with three replications. The moisture level in one of the experiments was optimum (100% field capacity while the second experiment was conducted under drought stress (45% field capacity. Several biochemical components including antioxidant enzymes and hydrogen peroxide and some physiological traits were analyzed in the two conditions. Drought stress significantly increased antioxidant activity at the grain filling stage. Superoxide dismutase activity showed the highest increase. Lipid peroxidation, hydrogen peroxide, electrolyte leakage and cell death increased significantly under drought condition, however membrane stability index decreased. Resistant cultivars showed the highest antioxidant activity and the lowest lipid peroxidation, hydrogen peroxide, and electrolyte leakage. This trend was reversed in the susceptible cultivars. Peroxidase and superoxide dismutase had a significant correlation with yield stability index. Hydrogen peroxide and cell membrane stability indices showed the highest correlation with yield stability index. Also Pishtaz and Alamut were selected respectively as the most resistance and susceptible cultivars.

  3. Development of marker-free transgenic lettuce resistant to Mirafiori lettuce big-vein virus.

    Science.gov (United States)

    Kawazu, Yoichi; Fujiyama, Ryoi; Imanishi, Shunsuke; Fukuoka, Hiroyuki; Yamaguchi, Hirotaka; Matsumoto, Satoru

    2016-10-01

    Lettuce big-vein disease caused by Mirafiori lettuce big-vein virus (MLBVV) is found in major lettuce production areas worldwide, but highly resistant cultivars have not yet been developed. To produce MLBVV-resistant marker-free transgenic lettuce that would have a transgene with a promoter and terminator of lettuce origin, we constructed a two T-DNA binary vector, in which the first T-DNA contained the selectable marker gene neomycin phosphotransferase II, and the second T-DNA contained the lettuce ubiquitin gene promoter and terminator and inverted repeats of the coat protein (CP) gene of MLBVV. This vector was introduced into lettuce cultivars 'Watson' and 'Fuyuhikari' by Agrobacterium tumefaciens-mediated transformation. Regenerated plants (T0 generation) that were CP gene-positive by PCR analysis were self-pollinated, and 312 T1 lines were analyzed for resistance to MLBVV. Virus-negative plants were checked for the CP gene and the marker gene, and nine lines were obtained which were marker-free and resistant to MLBVV. Southern blot analysis showed that three of the nine lines had two copies of the CP gene, whereas six lines had a single copy and were used for further analysis. Small interfering RNAs, which are indicative of RNA silencing, were detected in all six lines. MLBVV infection was inhibited in all six lines in resistance tests performed in a growth chamber and a greenhouse, resulting in a high degree of resistance to lettuce big-vein disease. Transgenic lettuce lines produced in this study could be used as resistant cultivars or parental lines for breeding.

  4. Lettuce seeds production in hydroponic system

    OpenAIRE

    Menezes, Nilson Lemos de; Santos, Osmar Souza dos; Schmidt, Denise

    2001-01-01

    Sementes de alface das cultivares Deyse e Regina foram produzidas em estufa, no sistema hidropônico, com elevados rendimentos por planta e boa qualidade de sementes, quando comparados a resultados de sistema convencional, de canteiros em campo. Esses dados sugerem estudos de produção de sementes de alface em cultivo protegido.Lettuce seeds of Deyse and Regina cultivars were produced in greenhouse, in hydroponic system, with excelents rendiments per plant and seed quality, when compared to con...

  5. Water lettuce

    African Journals Online (AJOL)

    Nutritive values, Mineral and Antioxidant properties of Pistia stratiotes (Water lettuce). 1R .S.U. Wasagu ... The use of plants as medicines predates written human history and some of ... used to maintain health, as well as to prevent, diagnose ...

  6. Modelling concept of lettuce breeding for nutrient efficiency

    NARCIS (Netherlands)

    Kerbiriou, P.J.; Stomph, T.J.; Lammerts Van Bueren, E.; Struik, P.C.

    2014-01-01

    Modern lettuce cultivars are bred for use under high levels of input of water and nutrients, and therefore less adapted to low-input or organic conditions in which nitrate availability varies over time and within the soil profile. To create robust cultivars it is necessary to assess which traits

  7. Concomitant uptake of antimicrobials and Salmonella in soil and into lettuce following wastewater irrigation

    International Nuclear Information System (INIS)

    Sallach, J. Brett; Zhang, Yuping; Hodges, Laurie; Snow, Daniel; Li, Xu; Bartelt-Hunt, Shannon

    2015-01-01

    The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and 125 ng/g fresh weight, respectively. Antimicrobial concentrations in lettuce decreased from the first to the third harvest suggesting that the plant growth rate may exceed antimicrobial uptake rates. Accumulation of antimicrobials was significantly different between cultivars demonstrating a subspecies level variation in uptake of antibiotics in lettuce. - Highlights: • Antimicrobial uptake in lettuce is cultivar dependent. • Antimicrobial concentrations in lettuce decrease despite repeated exposure. • Lincomycin is better conserved in the soil-plant system than oxytetracycline or sulfamethoxazole. • Subirrigation resulted in more Salmonella in bottom soil than in top soil. • Internalization frequency of Salmonella in lettuce is low despite repeated exposure. - Cultivar-specific differences in lincomycin and sulfamethazine uptake were observed in lettuce, while uptake of Salmonella was low despite repeated exposure from wastewater

  8. The alleviating effect of elevated CO2 on heat stress susceptibility of two wheat (Triticum aestivum L.) cultivars

    DEFF Research Database (Denmark)

    Kjær, Katrine Heinsvig; Ottosen, Carl-Otto; Rosenqvist, Eva S. K.

    2013-01-01

    efficiency of photosystem II (PSII) photochemistry (Fv/Fm) and contents of pigments and carbohydrates in leaves were analysed before and during the stress treatments as well as after one day of recovery. Heat stress reduced PN and Fv/Fm in both wheat cultivars, but plants grown in elevated CO2 maintained...... higher PN and Fv/Fm in comparison to plants grown in ambient CO2. Heat stress reduced leaf chlorophyll contents and increased leaf sucrose contents in both cultivars grown at ambient and elevated CO2. The content of hexoses in the leaves increased mainly in the tolerant cultivar in response...... to the combination of elevated CO2 and heat stress. The results show that heat stress tolerance in wheat is related to cultivar origin, the phenological stage of the plants and can be alleviated by elevated CO2. This confirms the complex interrelation between environmental factors and genotypic traits that influence...

  9. Abscisic acid content and the expression of genes related to its metabolism during maturation of triticale grains of cultivars differing in pre-harvest sprouting susceptibility.

    Science.gov (United States)

    Fidler, Justyna; Zdunek-Zastocka, Edyta; Prabucka, Beata; Bielawski, Wiesław

    2016-12-01

    Abscisic acid (ABA) is a plant hormone that plays a predominant role in the onset and maintenance of primary dormancy. Peak ABA accumulation in embryos of triticale grains was observed before any significant loss of water and was higher in Fredro, a cultivar less susceptible to pre-harvest sprouting (PHS), than in Leontino, a cultivar more sensitive to PHS. At full maturity, embryonic ABA content in Fredro was twice as high as in Leontino. Two full-length cDNAs of 9-cis-epoxycarotenoid dioxygenase (TsNCED1, TsNCED2), an enzyme involved in ABA biosynthesis, and two full-length cDNAs of ABA 8'-hydroxylase (TsABA8'OH1 and TsABA8'OH2), an enzyme involved in ABA catabolism, were identified in triticale grains and characterized. The maximum transcript level of both TsNCED1 and TsNCED2 preceded the peak of ABA accumulation, suggesting that both TsNCEDs contribute to reach this peak, although the expression of TsNCED1 was significantly higher in Fredro than in Leontino. High expression of TsABA8'OH2 and TsABA8'OH1 was observed long before and at the end of the ABA accumulation peak, respectively, but no differences were observed between cultivars. The obtained results suggest that mainly TsNCED1 might be related to the higher ABA content and higher resistance of Fredro to PHS. However, Fredro embryos not only have higher ABA content, but also exhibit greater sensitivity to ABA, which may also have a significant effect on grain dormancy and lower susceptibility to PHS for grains of this cultivar. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Evaluation of the CBL family gene expression under drought stress and virus attack in two susceptible and drought tolerant tomato cultivars using semi-quantitative PCR analysis

    Directory of Open Access Journals (Sweden)

    Peyman Aghaie

    2017-08-01

    Full Text Available Eleven genes encoding Calcineurin B-Like proteins with a high degree of sequence conservation were identified using bioinformatics approaches in tomato. These proteins classified into five clusters including SlCBL1, SlCBL3, SlCBL4, SlCBL8 and SlCBL10 using orthology-based method of nomenclature. Sequence analysis showed that all five members of SlCBL1 and SlCBL4 contained a myristoylation conserved motif (MGXXXS/T at their N-terminals. Semi-quantitative RT-PCR showed that among the SlCBL1 members, SlCBL1-3 up-regulated under both drought and virus stresses, as well as the combined treatment. Although, both SlCBL3-1 and SlCBL3-2 up-regulated under both drought and virus stresses in both susceptive and resistant cultivars, the combined stress did not have any additional effect on the expression. Among SlCBL4 members, only SlCBL4-1 up-regulated under drought or virus attack. There was a diverse pattern of expression between the two SlCBL8 members under different stresses in both cultivars. SlCBL10 showed no change in expression pattern under drought or virus stresses in susceptive cultivar and this gene showed to be up-regulated under drought in resistant cultivar. Overall, it was concluded that changes in the expression pattern of CBL genes under biotic and abiotic stresses seemingly induced various CBL/CIPK patways in suseptive or resistant plants.

  11. Baby leaf lettuce germplasm enhancement: developing diverse populations with resistance to bacterial leaf spot caused by Xanthomonas campestris pv. vitians

    Science.gov (United States)

    Baby leaf lettuce cultivars with resistance to bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) are needed to reduce crop losses. The objectives of this research were to assess the genetic diversity for BLS resistance in baby leaf lettuce cultivars and to select early gen...

  12. Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State Prevalência da estirpe comum de Lettuce mosaic virus em três regiões produtoras de alface do estado de São Paulo

    Directory of Open Access Journals (Sweden)

    Ana Carolina Firmino

    2008-06-01

    Full Text Available LMV is one of the most important pathogens of lettuce worldwide. Based on their ability to overcome the resistance genes mo1¹ and mo1² in lettuce, isolates can be divided in two types: LMV-Most, which can infect and are seed-borne in cultivars containing the mo1 gene and LMV-Common, which do not cause symptoms on these cultivars and are seed transmitted only in susceptible cultivars. To evaluate the occurrence of these two types of LMV isolates, a survey was carried out during 2002-2005 in three lettuce production areas from São Paulo State. Total RNA was used for the diagnosis of LMV isolates by RT-PCR using universal primers for the variable N-terminus of the capsid protein, in the 3' end of the genome. Positives samples were analyzed by a second RT-PCR using specifics primers for LMV-Most isolates designed to amplify a fragment from the central region (CI-VPg of the genome. A total of 1362 samples showing mosaic symptoms were collected and 504 (37.29 % were positives for LMV. On susceptible lettuce cultivars, LMV-Common was prevalent (77.3%. LMV-Most was found frequently associated with tolerant (mo1¹ lettuce cultivars. Susceptible cultivars correspond today for most of the area of lettuce production. So, despite the ability of LMV-Most isolates to overcome the resistance provided by the recessive mo1¹ gene, they are not prevalent in the conditions of São Paulo State.O LMV ocorre em todo o mundo e é considerado um dos patógenos mais importantes para a cultura da alface. De acordo com a habilidade em contornar os genes de resistência mo1¹ e mo1² encontrados em alface, os isolados de LMV podem ser dividos em dois sub-grupos: LMV-Most, capazes de contornar a resistência propiciada por estes genes e de serem transmitidos pela semente nestas cutivares, e LMV-Common, que não são capazes de causar sintomas nestes cultivares, além de serem transmitidos pela semente somente em cultivares suscetíveis. Para avaliar a ocorrência destes

  13. Evidence for Lettuce big-vein associated virus as the causal agent of a syndrome of necrotic rings and spots in lettuce

    NARCIS (Netherlands)

    Verbeek, M.; Dullemans, A.M.; Bekkum, van P.J.; Vlugt, van der R.A.A.

    2013-01-01

    Lettuce big-vein associated virus (LBVaV, genus Varicosavirus) was shown to be responsible for characteristic necrotic symptoms observed in combination with big-vein symptoms in lettuce breeding lines when tested for their susceptibility to lettuce big-vein disease (BVD) using viruliferous Olpidium

  14. Drought and Heat Differentially Affect XTH Expression and XET Activity and Action in 3-Day-Old Seedlings of Durum Wheat Cultivars with Different Stress Susceptibility.

    Science.gov (United States)

    Iurlaro, Andrea; De Caroli, Monica; Sabella, Erika; De Pascali, Mariarosaria; Rampino, Patrizia; De Bellis, Luigi; Perrotta, Carla; Dalessandro, Giuseppe; Piro, Gabriella; Fry, Stephen C; Lenucci, Marcello S

    2016-01-01

    Heat and drought stress have emerged as major constraints for durum wheat production. In the Mediterranean area, their negative effect on crop productivity is expected to be exacerbated by the occurring climate change. Xyloglucan endotransglucosylase/hydrolases (XTHs) are chief enzymes in cell wall remodeling, whose relevance in cell expansion and morphogenesis suggests a central role in stress responses. In this work the potential role of XTHs in abiotic stress tolerance was investigated in durum wheat. The separate effects of dehydration and heat exposure on XTH expression and its endotransglucosylase (XET) in vitro activity and in vivo action have been monitored, up to 24 h, in the apical and sub-apical root regions and shoots excised from 3-day-old seedlings of durum wheat cultivars differing in stress susceptibility/tolerance. Dehydration and heat stress differentially influence the XTH expression profiles and the activity and action of XET in the wheat seedlings, depending on the degree of susceptibility/tolerance of the cultivars, the organ, the topological region of the root and, within the root, on the gradient of cell differentiation. The root apical region was the zone mainly affected by both treatments in all assayed cultivars, while no change in XET activity was observed at shoot level, irrespective of susceptibility/tolerance, confirming the pivotal role of the root in stress perception, signaling, and response. Conflicting effects were observed depending on stress type: dehydration evoked an overall increase, at least in the apical region of the root, of XET activity and action, while a significant inhibition was caused by heat treatment in most cultivars. The data suggest that differential changes in XET action in defined portions of the root of young durum wheat seedlings may have a role as a response to drought and heat stress, thus contributing to seedling survival and crop establishment. A thorough understanding of the mechanisms underlying

  15. Susceptibility of low-chill blueberry cultivars to oriental fruit fly, mediterranean fruit fly, and melon fly (Diptera: Tephritidae)

    Science.gov (United States)

    Forced infestation studies were conducted to determine if fruits of southern highbush blueberries (Vaccinium corymbosum L. hybrids) are hosts for three invasive tephritid fruit flies. Fruits of 17 blueberry cultivars were exposed to gravid female flies of Bactrocera dorsalis (Hendel) (oriental frui...

  16. Concomitant uptake of antimicrobials and Salmonella in soil and into lettuce following wastewater irrigation.

    Science.gov (United States)

    Sallach, J Brett; Zhang, Yuping; Hodges, Laurie; Snow, Daniel; Li, Xu; Bartelt-Hunt, Shannon

    2015-02-01

    The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and 125 ng/g fresh weight, respectively. Antimicrobial concentrations in lettuce decreased from the first to the third harvest suggesting that the plant growth rate may exceed antimicrobial uptake rates. Accumulation of antimicrobials was significantly different between cultivars demonstrating a subspecies level variation in uptake of antibiotics in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Comparative Infection Progress Analysis of Lettuce big-vein virus and Mirafiori lettuce virus in Lettuce Crops by Developed Molecular Diagnosis Techniques.

    Science.gov (United States)

    Navarro, Jose A; Botella, Francisco; Maruhenda, Antonio; Sastre, Pedro; Sánchez-Pina, M Amelia; Pallas, Vicente

    2004-05-01

    ABSTRACT Nonisotopic molecular dot blot hybridization technique and multiplex reverse transcription-polymerase chain reaction assay for the specific detection of Lettuce big-vein virus (LBVV) and Mirafiori lettuce virus (MiLV) in lettuce tissue were developed. Both procedures were suitable for the specific detection of both viruses in a range of naturally infected lettuce plants from various Spanish production areas and seven different cultivars. The study of the distribution of both viruses in the plant revealed that the highest concentration of LBVV and MiLV occurred in roots and old leaves, respectively. LBVV infection progress in a lettuce production area was faster than that observed for MiLV. In spite of different rates of virus infection progress, most lettuce plants became infected with both viruses about 100 days posttransplant. The appearance of both viruses in lettuce crops was preceded by a peak in the concentration of resting spores and zoosporangia of the fungus vector Olpidium brassicae in lettuce roots.

  18. Screening of lettuce germplasm for agronomic traits under low water conditions

    Science.gov (United States)

    After a preliminary screening of over 3,500 varieties, we selected 200 cultivars of butterhead, cos, crisphead, leaf, and stem lettuce (Lactuca sativa L.) and wild prickly lettuce (Lactuca serriola L.) to test under high water (150% ET) and low water (50% ET) conditions in the field, and tracked com...

  19. The effect of co-infestation by conspecific and heterospecific aphids on the feeding behaviour of Nasonovia ribisnigri on resistant and susceptible lettuce cultivars

    NARCIS (Netherlands)

    Broeke, ten Cindy J.M.; Dicke, Marcel; Loon, van Joop J.A.

    2017-01-01

    Aphid saliva can suppress the blocking of sieve elements, a reaction that plants employ to inhibit aphid feeding, but aphid saliva can also elicit plant defence responses. Such plant responses might affect interactions between different aphid species and intraspecifically, e.g. among different

  20. Partial aphid resistance in lettuce negatively affects parasitoids.

    Science.gov (United States)

    Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

    2014-10-01

    This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids.

  1. Susceptibility of 15 mango (Sapindales: Anacardiaceae) cultivars to the attack by Anastrepha ludens and Anastrepha obliqua (Diptera:Tephritidae) and the role of underdeveloped fruit as pest reservoirs: management implications

    Science.gov (United States)

    We evaluated the susceptibility of 15 mango cultivars to the attack of Anastrepha ludens and A. obliqua, the main Tephritid pests of this crop in Mexico. In a field experiment, bagged, fruit-bearing branches were exposed to gravid females of both fly species. Infestation rates, developmental time,...

  2. Lettuce contact allergy.

    Science.gov (United States)

    Paulsen, Evy; Andersen, Klaus E

    2016-02-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Lettuce contact allergy

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus E

    2016-01-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...... person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy.......Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...... new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22...

  4. Physiological analysis of methods to relieve dormancy of lettuce seeds

    NARCIS (Netherlands)

    Weges, R.

    1987-01-01

    Low maximum temperature of germination restricts the cultivation of a number of lettuce cultivars to temperate conditions. Pretreatments have been studied that increase the maximum germination temperature, which is characterized by the temperature for 50% germination (T

  5. Developing lettuce with improved quality for processed salads.

    Science.gov (United States)

    Lettuce is increasingly consumed as minimally processed salads. Cultivars grown for this market may require breeding for improved shelf-life and resistance to physiological defects such as tipburn (TB). Tipburn is a calcium deficiency related defect causing necrosis on the leaf margins, typically on...

  6. Suscetibilidade de oito cultivares de bananeira à sigatoka-amarela na região de Marília (SP Susceptibility to sigatoka of eight banana cultivars in the region of Marília, State of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Junqueira Teixeira

    1996-01-01

    Full Text Available A suscetibilidade de oito cultivares de bananeira à sigatoka-amarela (Mycosphaerella musicola foi avaliada em um experimento de campo, na região de Marília (SP. Três cultivares pertenciam ao Grupo AAA ('Nanicão', 'Nanicão Jangada' e 'Grande Naine' e cinco, ao AAB ('Prata', 'Enxerto', 'Maçã', 'Mysore' e 'Prata Zulu'. O experimento foi implantado em fevereiro de 1992 e, durante os três primeiros anos, não foi feito controle de sigatoka. A suscetibilidade dos materiais foi estimada mediante avaliações em três épocas: março de 93, abril e julho de 94. Na primeira avaliação, foi contado o número de manchas na segunda folha e, nas outras, foram atribuídas notas de acordo com a intensidade dos sintomas. Os cultivares foram agrupados em três classes: altamente suscetível (AS, suscetível (S ou parcialmente resistente (PR. Nenhum dos cultivares pôde ser considerado imune, pois todos apresentaram lesões foliares. Os cultivares mais suscetíveis foram os do Grupo AAA, Subgrupo Cavendish ('Nanicão', 'Grande Naine' e 'Nanicão Jangada' e 'Enxerto' (AAB. 'Mysore' (AAB e 'Prata Zulu' (AAB foram classificados como parcialmente resistentes. 'Prata' (AAB e 'Maçã' (AAB mostraram-se medianamente suscetíveis.Susceptibility of eight banana cultivars to sigatoka caused by Mycosphaerella musicola was assessed in a field experiment in the region of Marília, State of São Paulo. Three cultivars were members of AAA Group ('Nanicão', 'Nanicão Jangada' and 'Grande Naine' and five belonged to AAB Group ('Prata', 'Enxerto', 'Maçã', 'Mysore' and 'Prata Zulu'. The experiment was established in February, 1992, and during the first three years, sigatoka disease was not controlled. Susceptibility was assessed in three occasions: March, 1993, April and July, 1994. In the first, it was counted the number of spots on the second leaf, and in the others, the plants were graded according to the amount of leaf scorch due to sigatoka. The cultivars were

  7. Biochemical study of leaf browning in minimally processed leaves of lettuce (Lactuca sativa L. var. acephala).

    Science.gov (United States)

    Degl'Innocenti, E; Guidi, L; Pardossi, A; Tognoni, F

    2005-12-28

    A series of biochemical parameters, including the concentration of total ascorbic acid (ASA(tot)) and the activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidases (PODs), was investigated during cold storage (72 h at 4 degrees C in the dark) in fresh-cut (minimally processed) leaves of two lettuce (Lactuca sativa L. var. acephala) cultivars differing in the susceptibility to tissue browning: Green Salade Bowl (GSB), susceptible, and Red Salade Bowl (RSB), resistant. The two cultivars showed differences also at the biochemical level. The content in ASA(tot) increased in RSB, as a consequence of increased DHA concentration; conversely, ASA(tot) diminished in GSB, in which ASA was not detectable after 72 h of storage, thus suggesting a disappearance of ascorbate (both ASA and DHA) into nonactive forms. The antioxidant capacity (as determined by using FRAP analysis) decreased significantly during storage in RSB, while a strong increase was observed in GSB. PAL activity increased soon after processing reaching a maximum by 3 h, then it declined to a relatively constant value in RSB, while in GSB it showed a tendency to decrease in the first few hours from harvest and processing. POD activity, at least for chlorogenic acid, increased significantly during storage only in GSB.

  8. AND DEVELOPMENT OF LETTUCE ON CHERNOZEM ORDINARY

    Directory of Open Access Journals (Sweden)

    N. V. Gromakova

    2017-01-01

    Full Text Available Lettuce is very popular in the Russian consumer market. Special conditions for its cultivation determine the need to select modern, inexpensive elements of agro-technology that promote high yields. At present biochar (bio-coal is considered as a promising organic fertilizer. Its main difference lies in the possibility of using any organic raw material in its production. In Russia, the study on the use of biochar is limited; there is no practice of applying it in the complex of agricultural techniques of various agricultural crops. In the conditions of vegetative experiment, the influence of various doses of biochar in ordinary chernozem on the growth and development of lettuce (Lactuca sativa cultivar was studied in accordance with the developed experiment scheme: control (without biochar, supplemented with 1, 2 and 5 % of biochar. In the experiment, biochar obtained from birch wood was used, by pyrolysis method in fraction of 0.5-5mm. The following observations and determinations were made: the timing of the onset of the phases of plant development, the length of the roots, the number of leaves, the length of the largest leaf, the height of plants, the diameter of the rosette, the mass of 10 plants. The use of biochar contributed to a reduction of beginning period technical ripeness in plants, particularly in variant with the addition of 2%. The increase in root length, the number of leaves of lettuce plants as compared with to control in variants with 2 and 5% of biocar has been observed. The length of the largest leaf, the height of plants and the diameter of the rosette of lettuce are characterized by a significant improvement, even in variant with 1%. Productivity of lettuce was highest in the variant with 2% of biochar applied to the soil.

  9. Beneficial Phytochemicals with Anti-Tumor Potential Revealed through Metabolic Profiling of New Red Pigmented Lettuces (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Xiao-Xiao Qin

    2018-04-01

    Full Text Available The present study aimed to compare polyphenols among red lettuce cultivars and identify suitable cultivars for the development and utilization of healthy vegetables. Polyphenols, mineral elements, and antioxidant activity were analyzed in the leaves of six red pigmented lettuce (Lactuca sativa L. cultivars; thereafter, we assessed the anti-tumor effects of cultivar B-2, which displayed the highest antioxidant activity. Quadrupole–Orbitrap mass spectrometry analysis revealed four classes of polyphenols in these cultivars. The composition and contents of these metabolites varied significantly among cultivars and primarily depended on leaf color. The B-2 cultivar had the highest antioxidant potential than others because it contained the highest levels of polyphenols, especially anthocyanin, flavone, and phenolic acid; furthermore, this cultivar displayed anti-tumor effects against the human lung adenocarcinoma cell line A549, human hepatoma cell line Bel7402, human cancer colorectal adenoma cell line HCT-8, and HT-29 human colon cancer cell line. Hence, the new red-leaf lettuce cultivar B-2 has a distinct metabolite profile, with high potential for development and utilization of natural phytochemical and mineral resources in lettuces and can be used as a nutrient-dense food product.

  10. Beneficial Phytochemicals with Anti-Tumor Potential Revealed through Metabolic Profiling of New Red Pigmented Lettuces (Lactuca sativa L.).

    Science.gov (United States)

    Qin, Xiao-Xiao; Zhang, Ming-Yue; Han, Ying-Yan; Hao, Jing-Hong; Liu, Chao-Jie; Fan, Shuang-Xi

    2018-04-11

    The present study aimed to compare polyphenols among red lettuce cultivars and identify suitable cultivars for the development and utilization of healthy vegetables. Polyphenols, mineral elements, and antioxidant activity were analyzed in the leaves of six red pigmented lettuce ( Lactuca sativa L.) cultivars; thereafter, we assessed the anti-tumor effects of cultivar B-2, which displayed the highest antioxidant activity. Quadrupole-Orbitrap mass spectrometry analysis revealed four classes of polyphenols in these cultivars. The composition and contents of these metabolites varied significantly among cultivars and primarily depended on leaf color. The B-2 cultivar had the highest antioxidant potential than others because it contained the highest levels of polyphenols, especially anthocyanin, flavone, and phenolic acid; furthermore, this cultivar displayed anti-tumor effects against the human lung adenocarcinoma cell line A549, human hepatoma cell line Bel7402, human cancer colorectal adenoma cell line HCT-8, and HT-29 human colon cancer cell line. Hence, the new red-leaf lettuce cultivar B-2 has a distinct metabolite profile, with high potential for development and utilization of natural phytochemical and mineral resources in lettuces and can be used as a nutrient-dense food product.

  11. Phosphorus rates on yield and quality of lettuce seeds

    OpenAIRE

    Kano,Cristiaini; Cardoso,Antonio Ismael Inácio; Bôas,Roberto L Villas

    2012-01-01

    Because of lack of information about phosphorus fertilization in lettuce from the standpoint of seed production, this study was undertaken. The work was carried out in Botucatu, São Paulo state, Brazil, from September 25, 2003 to February 19, 2004, in order to study the influence of crescents phosphorus rates on yield and quality of lettuce seeds, cultivar Verônica. The experimental design was randomized blocks with five treatments (0; 200; 400; 600 and 800 kg ha-1 of P2O5) and five replicati...

  12. Recurring off-types in lettuce: Their significance in plant breeding and seed production.

    Science.gov (United States)

    Maxon Smith, J W

    1977-03-01

    The lettuce cv. Valentine regularly produces non-heading off-type plants at the relatively high frequency of 4 × 10(-3). They result from mutation to the dominant condition. A similar propensity has been reported twice before in lettuce; it is highly heritable.The propensity to produce off-types was not present in the parents of Valentine so it must have arisen during the pedigree breeding programme. Closely related cultivars do not carry the character but it was subsequently transmitted to Dandie a new cultivar of which Valentine was one of the parents. Allelism tests to relate Valentine off-types to those in crisphead cultivars were not successful.The elimination of off-types in breeding programmes is discussed. Contrary to the findings in day-neutral crisphead cultivars, mutant phenotypes in long-day butterhead cultivars have no selective advantage for seed production. Consequently, strict roguing ensures adequate varietal stability.

  13. Resistance to Downy Mildew in Lettuce 'La Brillante' is Conferred by Dm50 Gene and Multiple QTL.

    Science.gov (United States)

    Simko, Ivan; Ochoa, Oswaldo E; Pel, Mathieu A; Tsuchida, Cayla; Font I Forcada, Carolina; Hayes, Ryan J; Truco, Maria-Jose; Antonise, Rudie; Galeano, Carlos H; Michelmore, Richard W

    2015-09-01

    Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar 'La Brillante' has a high level of field resistance to the disease in California. Testing of a mapping population developed from a cross between 'Salinas 88' and La Brillante in multiple field and laboratory experiments revealed that at least five loci conferred resistance in La Brillante. The presence of a new dominant resistance gene (designated Dm50) that confers complete resistance to specific isolates was detected in laboratory tests of seedlings inoculated with multiple diverse isolates. Dm50 is located in the major resistance cluster on linkage group 2 that contains at least eight major, dominant Dm genes conferring resistance to downy mildew. However, this Dm gene is ineffective against the isolates of B. lactucae prevalent in the field in California and the Netherlands. A quantitative trait locus (QTL) located at the Dm50 chromosomal region (qDM2.2) was detected, though, when the amount of disease was evaluated a month before plants reached harvest maturity. Four additional QTL for resistance to B. lactucae were identified on linkage groups 4 (qDM4.1 and qDM4.2), 7 (qDM7.1), and 9 (qDM9.2). The largest effect was associated with qDM7.1 (up to 32.9% of the total phenotypic variance) that determined resistance in multiple field experiments. Markers identified in the present study will facilitate introduction of these resistance loci into commercial cultivars of lettuce.

  14. The Alleviating Effect of Elevated CO2 on Heat Stress Susceptibility of Two Wheat (Triticum aestivum L.) Cultivars

    DEFF Research Database (Denmark)

    Shanmugam, Sindhuja; Kjær, Katrine Heinsvig; Ottosen, Carl-Otto

    2013-01-01

    This study analysed the alleviating effect of elevated CO2 on stress-induced decreases in photosynthesis and changes in carbohydrate metabolism in two wheat cultivars (Triticum aestivum L.) of different origin. The plants were grown in ambient (400 μl l−1) and elevated (800 μl l−1) CO2 with a day...... in leaves were analysed before and during the stress treatments as well as after 1 day of recovery. Heat stress reduced PN and Fv/Fm in both wheat cultivars, but plants grown in elevated CO2 maintained higher PN and Fv/Fm in comparison with plants grown in ambient CO2. Heat stress reduced leaf chlorophyll...... to cultivar origin, the phenological stage of the plants and can be alleviated by elevated CO2. This confirms the complex interrelation between environmental factors and genotypic traits that influence crop performance under various climatic stresses....

  15. Antioxidant capacity and contents of phenols, ascorbic acid, β-carotene and lycopene in lettuce

    Directory of Open Access Journals (Sweden)

    Zdravković Jasmina M.

    2014-01-01

    Full Text Available The antioxidant activity of three lettuce varieties (Lactuca sativa L. Emerald, Vera and Neva, cultivated in two kinds of protected spaces, a glasshouse and a plastic greenhouse, under controlled conditions, was determined. The content of antioxidant compounds: total phenols, flavonoids, L-ascorbic acid, ß-carotene and lycopene, were determined in ethanolic extracts of the lettuce with spectrophotometric methods. The largest content of total phenols (78.98 ± 0.67 mg GAE/g of dry extract was found in ethanolic extract of the lettuce variety Neva cultivated in a plastic greenhouse, whereas the largest content of flavonoids (35.45 ± 0.95 mg RU/g of dry extract was displayed in the lettuce Emerald cultivated in a glasshouse. It was observed that the lettuce cultivated in the glasshouse contained a somewhat higher content of L-ascorbic acid than the lettuce same variety from plastic greenhouse. The content of lycopene in the examined lettuce is negligible, and the content of ß-carotene is low. On the other hand, the high content of phenolic components causes favourable antioxidant properties found in all varieties of examined lettuce. [Projekat Ministarstva nauke Republike Srbije, br. TR 31059: A new concept in breeding vegetable cultivars and hybrids designed for sustainable growing systems using biotechnological methods

  16. Comparação entre cultivares de soja quanto à preferência alimentar de Cerotoma arcuata e suscetibilidade a um isolado do vírus do mosaico severo do caupi Comparison among soybean cultivars concerning the feed preference of Cerotoma arcuata and susceptibility to an isolate of CpSMV

    Directory of Open Access Journals (Sweden)

    Fernando Javier Sanhueza Salas

    1998-01-01

    , mainly on soybean {Glycine max, bean (Phaseolus vulgaris and cowpea (Vigna unguiculata, the cowpea severe mosaic virus (CpSMV, vectored by Cerotoma arcuata, is one of the best known. An isolate of CpSMV, named CpSMV-SP, was found on the Southern coastal region of São Paulo State infecting Vigna luteola, and has been subsequently studied at the Laboratory of Phytopathological Virology and Physiopathology of the Biological Institute. The feeding preference trials of C. arcuata, on soybean cultivars, were performed as follows: leaf discs were placed in Petri dishes covered with plastic glass-shaped lids to form an "arena" in which a single beetle was confined, taking into consideration multiple choice (11 cultivars, or not (a sole cultivar. The tested cultivars were 'BR-4', 'COODEPEC-201', 'EMBRAPA-48', 'EMBRAPA-59', 'IAC-177IAC-15-1', 'IAC-20', 'IAC-100', 'IAS-5', 'IGUAÇU' and 'PL-1'. For the susceptibility evaluation of cultivars, CpSMV-SP was C. arcuata and mecanically inoculated. Results showed that the feeding preference of C. arcuata varied and that the vector did not feed on IAC-20 only. When mecanicaly inoculated, all cultivars were susceptible to CpSMV-SP however, IAC-20 and IAC-100 were not infected when inoculated by C. arcuata. The former, probably due to the vector not fed on it, and the latter because the vector presented low or no efficiency. Considering these results and the natural occurrence of CpSMV-SP, the use of the cultivars IAC-20 and IAC-100 could be recommended for São Paulo State.

  17. Laboratory and semi-field evaluation of Beauveria bassiana (Ascomycota: Hypocreales) against the lettuce aphid, Nasonovia ribisnigri (Hemiptera: Aphididae)

    DEFF Research Database (Denmark)

    Shrestha, Govinda; Enkegaard, Annie; Steenberg, Tove

    2015-01-01

    The lettuce aphid, Nasonovia ribisnigri (Mosley), is an economically important pest of lettuce worldwide. The entomopathogenic fungus Beauveria bassiana strain GHA has recently been reported as a potential biocontrol candidate for use against the lettuce aphid. This study provides information...... on the mortality inflicted by B. bassiana when applied against different life stages of the lettuce aphid under laboratory conditions and how fungus infection affects the aphid fecundity. In addition, temporal changes in persistence of fungus inoculum applied to foliage of young lettuce plants under semi......-field conditions was analysed. Immature life stages were generally the least susceptible to fungal infection and the susceptibility of all stages was dose-dependent, with the highest mortality occurring at the highest dose. B. bassiana significantly affected the rate of nymph production by the lettuce aphid...

  18. Partially resistant Cucurbita pepo showed late onset of the Zucchini yellow mosaic virus infection due to rapid activation of defense mechanisms as compared to susceptible cultivar

    Czech Academy of Sciences Publication Activity Database

    Nováková, S.; Flores-Ramirez, G.; Glasa, M.; Danchenko, M.; Fiala, R.; Škultéty, L'udovít

    2015-01-01

    Roč. 6, APR 2015 (2015), s. 1-14 ISSN 1664-462X Institutional support: RVO:61388971 Keywords : Cucurbita pepo cultivars * Zucchini yellow mosaic virus * resistance to phytopatogen Subject RIV: CE - Biochemistry Impact factor: 4.495, year: 2015

  19. (Lilium) cultivar

    African Journals Online (AJOL)

    Yomi

    2012-08-30

    Aug 30, 2012 ... 2National Engineering Research Center for Floriculture, Beijing, China. Accepted 6 August, 2012 ... hybrids lily cultivar 'eyeliner' was selected as the materials. By using the ... of sterilization was not ideal which led to higher.

  20. Wild lettuce (Lactuca virosa) toxicity

    OpenAIRE

    Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

    2009-01-01

    Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity...

  1. Transfer and expression of the rabbit defensin NP-1 gene in lettuce (Lactuca sativa).

    Science.gov (United States)

    Song, D; Xiong, X; Tu, W F; Yao, W; Liang, H W; Chen, F J; He, Z Q

    2017-01-23

    Lettuce (Lactuca sativa L.) is an annual plant of the daisy family, Asteraceae, with high food and medicinal value. However, the crop is susceptible to several viruses that are transmitted by aphids and is highly vulnerable to post-harvest diseases, as well as insect and mammal pests and fungal and bacterial diseases. Here, the rabbit defensin gene NP-1 was transferred into lettuce by Agrobacterium-mediated transformation to obtain a broad-spectrum disease-resistant lettuce. Transgenic lettuce plants were selected and regenerated on selective media. The presence of the NP-1 gene in these plants was confirmed by western blot analyses. Resistance tests revealed native defensin NP-1 expression conferred partial resistance to Bacillus subtilis and Pseudomonas aeruginosa, which suggests new possibilities for lettuce disease resistance.

  2. Cucumis sativus L-type lectin receptor kinase (CsLecRK) gene family response to Phytophthora melonis, Phytophthora capsici and water immersion in disease resistant and susceptible cucumber cultivars.

    Science.gov (United States)

    Wu, Tingquan; Wang, Rui; Xu, Xiaomei; He, Xiaoming; Sun, Baojuan; Zhong, Yujuan; Liang, Zhaojuan; Luo, Shaobo; Lin, Yu'e

    2014-10-10

    L-type lectin receptor kinase (LecRK) proteins are an important family involved in diverse biological processes such as pollen development, senescence, wounding, salinity and especially in innate immunity in model plants such as Arabidopsis and tobacco. Till date, LecRK proteins or genes of cucumber have not been reported. In this study, a total of 25 LecRK genes were identified in the cucumber genome, unequally distributed across its seven chromosomes. According to similarity comparison of their encoded proteins, the Cucumis sativus LecRK (CsLecRK) genes were classified into six major clades (from Clade I to CladeVI). Expression of CsLecRK genes were tested using QRT-PCR method and the results showed that 25 CsLecRK genes exhibited different responses to abiotic (water immersion) and biotic (Phytophthora melonis and Phytophthora capsici inoculation) stresses, as well as that between disease resistant cultivar (JSH) and disease susceptible cultivar (B80). Among the 25 CsLecRK genes, we found CsLecRK6.1 was especially induced by P. melonis and P. capsici in JSH plants. All these results suggested that CsLecRK genes may play important roles in biotic and abiotic stresses. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Secondary metabolism responses in two Pisum sativum L. cultivars ...

    African Journals Online (AJOL)

    Both cultivars were grown in the absence or presence of Fe with the addition of bicarbonate for twelve days. Higher concentrations of phenols and flavonoids were observed in Fe-deficient tissues of both cultivars; however, the increase was greater in the tolerant cultivar than in the susceptible one. The activity of shikimate ...

  4. Altered cultivar resistance of kimchi cabbage seedlings mediated by salicylic Acid, jasmonic Acid and ethylene.

    Science.gov (United States)

    Lee, Young Hee; Kim, Sang Hee; Yun, Byung-Wook; Hong, Jeum Kyu

    2014-09-01

    Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

  5. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    Directory of Open Access Journals (Sweden)

    Young Hee Lee

    2014-09-01

    Full Text Available Two cultivars Buram-3-ho (susceptible and CR-Hagwang (moderate resistant of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum, black spot (Alternaria brassicicola and black rot (Xanthomonas campestris pv. campestris, Xcc diseases in our previous study. Defense-related hormones salicylic acid (SA, jasmonic acid (JA and ethylene led to different transcriptional regulation of pathogenesis-related (PR gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

  6. CONSUMER ATTITUDES TOWARD ORGANICALLY GROWN LETTUCE

    OpenAIRE

    Wolf, Marianne McGarry; Johnson, Bradey; Cochran, Kerry; Hamilton, Lynn L.

    2002-01-01

    This research shows that approximately 29 percent of lettuce purchases in California expect to purchase an organically grown lettuce product in the future. Organic lettuce purchasers are more likely to be female, have a higher household income and a higher level of education. Consumers are concerned with the freshness, quality, price, and environmental impact of the lettuce they purchase.

  7. A rapid and efficient in vitro regeneration system for lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Armas, Isabel; Pogrebnyak, Natalia; Raskin, Ilya

    2017-01-01

    Successful biotechnological improvement of crop plants requires a reliable and efficient in vitro regeneration system. Lettuce ( Lactuca sativa L.), one the most important vegetable crops worldwide, is strongly genotype-dependent in terms of regeneration capacity, limiting the potential for biotechnological improvement of cultivars which show recalcitrance under currently available protocols. The effect of different nutrient sources, plant hormone combinations and activated charcoal supplementation on shoot induction efficiency was evaluated on the cultivar 'RSL NFR', which had previously shown poor regeneration efficiency. Multiple shoot organogenesis from cotyledon explants was recorded at the highest frequency and speed on Murashige and Skoog regeneration medium supplemented with 200 mg/l of activated charcoal, 3% sucrose, 10 mg/l benzylaminopurine and 0.5 mg/l naphthaleneacetic acid, which induced shoots through direct regeneration in 90.8 ± 7.9% of explants. High shoot induction efficiency was also observed, albeit not quantified, when using this medium on some other cultivars. This activated charcoal-containing regeneration medium might offer a rapid and efficient option for direct shoot induction in some lettuce genotypes that do not respond well to common lettuce regeneration protocols. This is also the first report of the effect of activated charcoal in lettuce tissue culture.

  8. Influence of stripe rust infection on the photosynthetic characteristics and antioxidant system of susceptible and resistant wheat cultivars at the adult plant stage.

    Science.gov (United States)

    Chen, Yang-Er; Cui, Jun-Mei; Su, Yan-Qiu; Yuan, Shu; Yuan, Ming; Zhang, Huai-Yu

    2015-01-01

    Wheat stripe rust (Puccinia striiformis f. sp. tritici, Pst), is one of the most serious diseases of wheat (Triticum aestivum L.) worldwide. To gain a better understanding of the protective mechanism against stripe rust at the adult plant stage, the differences in photosystem II and antioxidant enzymatic systems between susceptible and resistant wheat in response to stripe rust disease (P. striiformis) were investigated. We found that chlorophyll fluorescence and the activities of the antioxidant enzymes were higher in resistant wheat than in susceptible wheat after stripe rust infection. Compared with the susceptible wheat, the resistant wheat accumulated a higher level of D1 protein and a lower level of reactive oxygen species after infection. Furthermore, our results demonstrate that D1 and light-harvesting complex II (LHCII) phosphorylation are involved in the resistance to stripe rust in wheat. The CP29 protein was phosphorylated under stripe rust infection, like its phosphorylation in other monocots under environmental stresses. More extensive damages occur on the thylakoid membranes in the susceptible wheat compared with the resistant wheat. The findings provide evidence that thylakoid protein phosphorylation and antioxidant enzyme systems play important roles in plant responses and defense to biotic stress.

  9. Pathogenic Streptomyces spp. abundance affected by potato cultivars.

    Science.gov (United States)

    Nahar, Kamrun; Goyer, Claudia; Zebarth, Bernie J; Burton, David L; Whitney, Sean

    2018-04-16

    Potato cultivars vary in their tolerance to common scab (CS), however how they affect CS-causing Streptomyces spp. populations over time is poorly understood. This study investigated the effects of potato cultivar on pathogenic Streptomyces spp. abundance, measured using quantitative PCR, in three spatial locations in a CS-infested field: 1) soil close to the plant (SCP); 2) rhizosphere (RS); and 3) geocaulosphere (GS) soils. Two tolerant (Gold Rush, Hindenburg) and two susceptible cultivars (Green Mountain, Agria) were tested. The abundance of pathogenic Streptomyces spp. significantly increased in late August compared with other dates in RS of susceptible cultivars in both years. Abundance of pathogenic Streptomyces spp., when averaged over locations and time, was significantly greater in susceptible cultivars compared with tolerant cultivars in 2014. Principal coordinates analysis showed that SCP and RS soil properties (pH, organic carbon and nitrogen concentrations) explained 68% and 76% of total variation in Streptomyces spp. abundance among cultivars in 2013, respectively, suggesting that cultivars influenced CS pathogen growth conditions. The results suggested that the genetic background of potato cultivars influenced the abundance of pathogenic Streptomyces spp., with 5 to 6 times more abundant Streptomyces spp. in RS of susceptible cultivars compared with tolerant cultivars, which would result in substantially more inoculum left in the field after harvest.  .

  10. Molecular identification and biological characterization of a new potyvirus in lettuce.

    Science.gov (United States)

    Ciuffo, Marina; Mammella, Marco; Vallino, Marta; Caciagli, Piero; Turina, Massimo

    2016-09-01

    A potyvirus causing necrosis and leaf distortion on lettuce was found in the Lazio region of Italy. Host range analysis showed its ability to infect only Chenopodium quinoa and C. amaranticolor in addition to some lettuce cultivars. The virus could be transmitted by aphids of the species Myzus persicae. The complete 9829-nt genome was characterized. BLAST analysis of sequence of the complete encoded polyprotein showed that the most closely related virus is asparagus virus 1, with 52 % amino acid sequence identity. These results suggest that this virus should be considered a member of a new species in the genus Potyvirus.

  11. Nutrient absorption and response of lettuce to phosphorus fertilization

    OpenAIRE

    Antonio Ismael Inácio Cardoso; Cristiaini Kano; Roberto Lyra Villas Boas

    2012-01-01

    The objective of this study was to evaluate the response of lettuce (cultivar Verônica) to different levels of phosphorus fertilization. The experiment was conducted from 25/09/2003 (sowing) to 03/12/2003 (harvesting) at the Fazenda Experimental São Manuel, UNESP/FCA, Botucatu/SP, under protective structures. The experiment was conducted in a randomized block design, with five treatments (0, 200, 400, 600 and 800kg.ha-1 of P2O5, in the form of triple superphosphate) and five replications. Pla...

  12. Non-destructive prediction of pigment content in lettuce based on visible-NIR spectroscopy.

    Science.gov (United States)

    Steidle Neto, Antonio José; Moura, Lorena de Oliveira; Lopes, Daniela de Carvalho; Carlos, Lanamar de Almeida; Martins, Luma Moreira; Ferraz, Leila de Castro Louback

    2017-05-01

    Lettuce (Lactuca sativa L.) is one of the most important salad vegetables in the world, with a number of head shapes, leaf types and colors. The lettuce pigments play important physiological functions, such as photosynthetic processes and light stress defense, but they also benefit human health because of their antioxidant action and anticarcinogenic properties. In this study three lettuce cultivars were grown under different farming systems, and partial least squares models were built to predict the leaf chlorophyll, carotenoid and anthocyanin content. The three proposed models resulted in high coefficients of determination and variable importance for the projection values, as well as low estimative errors for calibration and external validation datasets. These results confirmed that it is possible to accurately predict chlorophyll, carotenoid and anthocyanin content of green and red lettuces, grown in different farming systems, based on the spectral reflectance from 500 to 1000 nm. The proposed models were adequate for estimating lettuce pigments in a quick and non-destructive way, representing an alternative to conventional measurement methods. Prediction accuracies were improved by using the detrending, smoothing and first derivative pretreatments to the original spectral signatures prior to estimating lettuce chlorophyll, carotenoid and anthocyanin content, respectively. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Media Effects on Lettuce Growth in "Pillows" Designed for the VEGGIE Spaceflight Growth Chamber

    Science.gov (United States)

    Massa, Gioia; Newsham, Gerard; McCoy, LaShelle; Stutte, Gary; Wheeler, Raymond

    2012-01-01

    VEGGIE is a prototype vegetable production unit for space designed by Orbital Technologies Corporation that is being developed to fly on the International Space Station. A modular plant rooting system "pillow" is being designed to support plant growth in VEGGIE under microgravity conditions. VEGGIE pillows are small self-contained packets of media with time-release fertilizer that can wick water passively from a root mat reservoir. Seeds are planted in pillows and the entire root system of a plant is contained as the crop develops, preventing loss into the spacecraft cabin. This study compared five media types and three lettuce cultivars in pillows growing in a VEGGIE analog environment.. Media consisted of a peat-based potting mix (Fafard #2,Conrad Fafard Inc., Agawam, MA), and a calcined clay, (arcillite, 1-2 mm sifted, Turface Proleague, Profile LLC, Buffalo Grove IL) as well as three different blends of the two, 70:30, 50:50, and 30:70. Lettuce cultivars tested were 'Sierra', a bi-colored French crisp Batavia lettuce, 'Outredgeous', a red romaine lettuce and 'Flandria', a green butter head variety. Plants were grown for 28 days, harvested, biometric data was obtained, and tissue mineral analysis was performed. For all cultivars, lettuce plants grown in the media blends were more productive than those in the individual media types. All cultivars showed bell-shaped curves in response to increases in arcillite / decreases in Fafard #2 for leaf area, fresh, and dry mass. Plants in 100% Fafard #2 and in 100% arcillite were stunted, but only those in higher levels of Fafard #2 (70% and 100%) had reduced shoot percent moisture, possibly indicating that mechanisms causing stunting differed. Variation in tissue nutrient content are consistent with this, with Mg and Mn highest in plants grown in 100% Fafard and decreasing as the concentration of arcillite increased. Color also varied with media, especially in the 'Sierra' lettuce, with plants grown in increasing levels

  14. Genetics of resistance in lettuce to races 1 and 2 of Verticillium dahliae from different host species

    Science.gov (United States)

    Race 1 resistance against Verticillium dahliae in lettuce was originally shown in the cultivar La Brillante to be conditioned by a single dominant gene (Verticillium resistance 1, Vr1). Multiple, morphologically diverse sources of germplasm have been identified as resistant to race 1. In this study...

  15. Wild lettuce (Lactuca virosa) toxicity.

    Science.gov (United States)

    Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

    2009-01-01

    Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity caused by wild lettuce intake and an accurate history formed the basis of the diagnosis. Conservative treatment, vital sign monitoring, control of patient intake and output, and reducing patient agitation provided the basis for treatment.

  16. Production and photosynthetic activity of Mimosa Verde and Mimosa Roxa lettuce in two farming systems

    Directory of Open Access Journals (Sweden)

    Aline Mabel Rosa

    2014-08-01

    Full Text Available Lettuce (Lactuca sativa L. is the most commonly consumed leaf vegetable in the Brazilian diet, and it is a good source of vitamins and minerals. It is widely grown in the conventional farming system. However, the hydroponic farming system has been gaining importance in the market, wining confidence from consumers, who are becoming increasingly more demanding on food quality. The objective of this study was to evaluate the performance of two lettuce cultivars on hydroponic and conventional farming systems for the production of fresh mass (FM and dry mass (DM, photosynthesis, contents of chlorophyll and anthocyanin. The following two experiments were carried out: hydroponics farming (HF and conventional farming (CF, performed in protect and unprotect environments, respectively, in Florianópolis, SC. Mimosa Verde cultivar (MV showed greater fresh mass than Mimosa Roxa (MR, in both farming systems and the two cultivars presented better performance in the hydroponic system (287.7 g MV and 139.1 g MR than the conventional system (129.7 g MV and 111.8 g MR. Mimosa Verde cultivar presented lower average contents of total chlorophyll (7.7 mg g-¹ FM than Mimosa Roxa (11.8 mg g-¹FM, and both cultivars displayed higher means for this variable in the hydroponic farming system. Mimosa Roxa presented higher contents of anthocyanin in the conventional system (88.24 mg g-¹ FM than the ones in the hydroponic system (36.89 mg g-¹ FM. The best results for CO2 net assimilation rate regarded to photosyntheticaly active photon flux density were found in the hydroponic system, for both lettuce cultivars. Variation in the contents of chlorophyll were also found. Those variations were higher in the protected system than in the hydroponic system and contents of anthocyanin were higher in the conventional system.

  17. Factors important for the shelf-life of minimally processed lettuce

    DEFF Research Database (Denmark)

    Deza Durand, Karla Michelle

    for a more comprehensive analyses as presented in paper IV. Paper III revealed that packaging and storage time had an influence on the volatiles of cut iceberg lettuce allowing the formation of desirable aroma but also on the development of off-odors. This result indicates that extremely low O2 and high CO2...... significantly higher in passive MAP F1. Regarding the cultivars, Morinas and Diamantinas was the less tolerant to high CO2 resulting in significantly higher amount of 2,3-butanedione. Paper V was related to browning and other physicochemical characteristics of minimally processed lettuce such as soluble sugars...... to influence the formation of browning and other physicochemical characteristics as storage time increased. It was concluded that browning was remarkable controlled in passive MAPs samples, irrespective of season and cultivar due to extremely low O2 and high CO2 conditions, however, after 11 days of storage...

  18. Comparative transcriptome profiling of a resistant vs. susceptible tomato (Solanum lycopersicum cultivar in response to infection by tomato yellow leaf curl virus.

    Directory of Open Access Journals (Sweden)

    Tianzi Chen

    Full Text Available Tomato yellow leaf curl virus (TYLCV threatens tomato production worldwide by causing leaf yellowing, leaf curling, plant stunting and flower abscission. The current understanding of the host plant defense response to this virus is very limited. Using whole transcriptome sequencing, we analyzed the differential gene expression in response to TYLCV infection in the TYLCV-resistant tomato breeding line CLN2777A (R and TYLCV-susceptible tomato breeding line TMXA48-4-0 (S. The mixed inoculated samples from 3, 5 and 7 day post inoculation (dpi were compared to non-inoculated samples at 0 dpi. Of the total of 34831 mapped transcripts, 209 and 809 genes were differentially expressed in the R and S tomato line, respectively. The proportion of up-regulated differentially expressed genes (DEGs in the R tomato line (58.37% was higher than that in the S line (9.17%. Gene ontology (GO analyses revealed that similar GO terms existed in both DEGs of R and S lines; however, some sets of defense related genes and their expression levels were not similar between the two tomato lines. Genes encoding for WRKY transcriptional factors, R genes, protein kinases and receptor (-like kinases which were identified as down-regulated DEGs in the S line were up-regulated or not differentially expressed in the R line. The up-regulated DEGs in the R tomato line revealed the defense response of tomato to TYLCV infection was characterized by the induction and regulation of a series of genes involved in cell wall reorganization, transcriptional regulation, defense response, ubiquitination, metabolite synthesis and so on. The present study provides insights into various reactions underlining the successful establishment of resistance to TYLCV in the R tomato line, and helps in the identification of important defense-related genes in tomato for TYLCV disease management.

  19. Tolerância ao florescimento precoce e características comerciais de progênies F4 de alface do cruzamento Regina 71 x Salinas 88 = Tolerance to precocious flowering and commerical traits of F4 progenies of hybrid Regina 71 x Salinas 88 lettuce

    Directory of Open Access Journals (Sweden)

    José Luiz Sandes de Carvalho Filho

    2009-01-01

    Full Text Available A alface é uma espécie cujas plantas possuem grande variabilidade no que diz respeito à forma, cor e textura das folhas, caracterizando diferentes tipos comerciais. O grupo folhas lisas ainda se mantém como um dos mais consumidos. A caracterização do tipo de folha é essencial no desenvolvimento de um programa de melhoramento,principalmente, quando a população segregante é oriunda de parentais contrastantes para o caráter. Além disso, a maior parte das cultivares utilizada é sensível ao calor, emitindo a haste floral precocemente. Assim, o objetivo deste trabalho foi avaliar características comercias de progênies F4 de alface e a sua tolerância ao calor, visando obter cultivares com folha lisa tolerantes ao florescimento precoce, resistentes aos nematóides e ao LMV. Avaliaram-se 22 progênies F4 originadas do cruzamento envolvendo as cultivares ‘Regina 71’ e ‘Salinas 88’, previamente selecionadas para tolerância ao calor, resistência aos nematóides das galhas e ao LMV (lettuce mosaic virus. O delineamento foi em blocos casualizados, com quatro repetições. Foram avaliados os tipos de limbo e borda foliares, formação de cabeça e número de dias para a primeira antese. Dentre as 22 progênies avaliadas, três mostraram-semais promissoras à obtenção de linhagens de alface de folhas lisas resistentes ao calor, nematóides das galhas e ao LMV.The lettuce is a plant that features great variability in form, color and texture. The butterleaf variety had remained one of themost consumed lettuce types. The evaluation of leaf type for commercial characters is essential for the development of any improvement program, especially when the parents are divergent types. Furthermore, most cultivars are susceptible to heat. Thus, the objective of the present work was to evaluate F4 progenies of butterleaf lettuce, aiming to select new genotypes for nematode resistance, tolerance to heat and LMV. Twenty-two F3:4 progenieswere

  20. Switchgrass cultivar EG1101

    Science.gov (United States)

    Bouton, Joseph H; Wood, Donald T

    2012-11-27

    A switchgrass cultivar designated EG1101 is disclosed. Also disclosed are seeds of switchgrass cultivar EG1101, plants of switchgrass EG1101, plant parts of switchgrass cultivar EG1101 and methods for producing a switchgrass plant produced by crossing switchgrass cultivar EG1101 with itself or with another switchgrass variety. Methods are also described for producing a switchgrass plant containing in its genetic material one or more transgenes and to the transgenic switchgrass plants and plant parts produced by those methods. Switchgrass cultivars or breeding cultivars and plant parts derived from switchgrass variety EG1101, methods for producing other switchgrass cultivars, lines or plant parts derived from switchgrass cultivar EG1101 and the switchgrass plants, varieties, and their parts derived from use of those methods are described herein. Hybrid switchgrass seeds, plants and plant parts produced by crossing the cultivar EG1101 with another switchgrass cultivar are also described.

  1. Switchgrass cultivar EG1102

    Science.gov (United States)

    Bouton, Joseph H; Wood, Donald T

    2012-11-20

    A switchgrass cultivar designated EG1102 is disclosed. The invention relates to the seeds of switchgrass cultivar EG1102, to the plants of switchgrass EG1102, to plant parts of switchgrass cultivar EG1102 and to methods for producing a switchgrass plant produced by crossing switchgrass cultivar EG1102 with itself or with another switchgrass variety. The invention also relates to methods for producing a switchgrass plant containing in its genetic material one or more transgenes and to the transgenic switchgrass plants and plant parts produced by those methods. This invention also relates to switchgrass cultivars or breeding cultivars and plant parts derived from switchgrass variety EG1102, to methods for producing other switchgrass cultivars, lines or plant parts derived from switchgrass cultivar EG1102 and to the switchgrass plants, varieties, and their parts derived from use of those methods. The invention further relates to hybrid switchgrass seeds, plants and plant parts produced by crossing the cultivar EG1102 with another switchgrass cultivar.

  2. Selenium accumulation in lettuce germplasm

    Science.gov (United States)

    Selenium (Se) is an essential micronutrient for animals and humans. Increasing Se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. In this study, we evaluated thirty diverse accessions of lettuce (Lactuca sativa L.) f...

  3. Variation of Citrus cultivars in Egypt assessed by RAPDs, cluster ...

    African Journals Online (AJOL)

    DR-Seham

    2012-11-13

    Nov 13, 2012 ... for the low productivity are inappropriate cultivation practices, old trees, lack ... the development of high yielding varieties (Golein et al.,. 2012). Thus .... maintained when trees are grown from seeds, cultivars are susceptible to ...

  4. Relative susceptibility of banana cultivars to Xanthomonas ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... African Journal of Biotechnology Vol. 8 (20), pp. 5343-5350, 19 ... and Central Africa. The disease was first reported about. 40 years ago in Ethiopia on Ensete, which is closely related to banana (Yirgou et al., 1968). Outside Ethiopia,. BXW was ... Economic impact of the disease is manifested as result of ...

  5. The phytoavailability of cadmium to lettuce in long-term biosolids-amended soils

    Energy Technology Data Exchange (ETDEWEB)

    Brown, S.L.; Chaney, R.L. [Dept. of Agriculture, Beltsville, MD (United States); Angle, J.S. [Univ. of Maryland, College Park, MD (United States). Dept. of Agronomy; Ryan, J.A. [Environmental Protection Agency, Cincinnati, OH (United States). National Risk Management Research Lab.

    1998-09-01

    A field study was conducted to assess the phytoavailability of Cd in long-term biosolids-amended plots managed at high and low pH. The experiment, established 13 to 15 yr prior to the present cropping, on a Christiana fine sandy loam soil used a variety of biosolids. Two of the biosolids had total Cd concentrations of 13.4 and 210 mg kg{sup {minus}1}. A Cd salt treatment, with Cd added to soil at a rate equivalent to the Cd added by the higher Cd biosolids applied at 100 Mg ha{sup {minus}1}, was also included. The lettuce (Lactuca sativa var. longifolia) cultivar (Paris Island Cos) used in the initial study was also used in the current study. Lettuce Cd was compared between treatments, and in relation to the soil Cd/soil organic C (OC) ratio. There has been no significant increase in plant Cd since the initial cropping. With 16% of the biosolids added OC remaining, lettuce grown on the soil amended with the more contaminated biosolids was not different than that of the initial cropping. Further, significantly less Cd was taken up by lettuce grown on biosolids-amended soil than lettuce grown on soil amended with equivalent rates of Cd salt. The Cd concentration in lettuce grown in the low Cd biosolids treatment was not different from the control. These results indicate that the potential hazards associated with food chain transfer of biosolids-applied Cd are substantially lower than equivalent Cd salt treatments, and that the hazards do not increase over time.

  6. Influence of hydrogel on germination of lettuce and onion seed at different moisture levels

    Directory of Open Access Journals (Sweden)

    Kateřina Pazderů

    2013-01-01

    Full Text Available The influence of Agrisorb (water solution 1, 3, 5 g/l on lettuce and onion seed germination was tested in different moisture conditions (30 ml and 15 ml of water in germination box. Variants with reduced water level germinated much more slowly (MGT parameter than standard variants, though differences in total germination at the end of the test were insignificant. Treated variants of lettuce seeds showed a statistically significant increase in germination energy (GE on the first day (GE1, both water levels, but a significant decrease on the second day (columns GE2, 15 ml. Higher doses of Agrisorb slowed lettuce seed germination (GE2, 30 ml, dose 5 g significantly, similarly see GE2 (15 ml, doses 1, 3, 5 g. This slowdown was apparent for GE3 (both water amount as well. A similar but insignificant effect was evident for onions. There was an influence of cultivar and seed vigour on sensitivity to water stress. The hydrogel application influenced germination of lettuce and onion seeds. Treated lettuce seeds germinated faster than non-treated control in the beginning of germination process. This effect was not recorded in case of slowly germinated onion seed lots. Although influence of Agrisorb was positive in the beginning, higher doses of hydrogel reduced germination energy of treated seed lots (for example GE2, GE4 of both crops in comparison with non-treated control. Higher doses of hydrogel caused longer MGT of lettuce and onion as well.

  7. Potential internalisation of caliciviruses in lettuce.

    Science.gov (United States)

    Urbanucci, A; Myrmel, M; Berg, I; von Bonsdorff, C-H; Maunula, L

    2009-10-31

    Fresh produce such as lettuce (Lactuca sativa) has often been linked to epidemic viral gastroenteritis. In these cases, it is unknown whether the viral contamination has occurred during the growing or the processing of the implicated product. In this study lettuce was grown in the presence of enteric viruses, and the uptake of viruses via the roots into the edible parts (leaves and stem) of the lettuce plants was investigated, for plants with both intact and damaged roots. The roots of lettuce, growing either in hydroponic culture or in soil, were exposed to canine calicivirus (CaCV) and a human genogroup 2 norovirus (HuNoV) by these being added into the water or soil in which the lettuce was growing. Leaves from lettuce plants and seedlings were examined for viruses by real-time RT-PCR. When the lettuce plants were exposed to very high concentrations of CaCV, the virus was detected in lettuce leaves, indicating contamination via the roots, but the frequency of positive results was low. Internalisation occurred in both seedlings and grown plants, in both hydroponic and soil cultures, and occurred whether the roots were intact or damaged. However, internalisation of HuNoV was not detected in any of the experimental set ups, although the concentrations to which the plants were exposed were relatively high. Based on these results, viral contamination of lettuce plants via roots cannot be excluded, but is apparently not an important transmission route for viruses.

  8. Cadmium and chromium effects on seed germination and root elongation in lettuce, spinach and Swiss chard

    Directory of Open Access Journals (Sweden)

    Oscar V Bautista

    2013-04-01

    Full Text Available The La Ramada district and the Bogota River are the principal water resources used for horticultural crop production on the Bogota Plateau, which contain channel pollutant materials, including heavy metals due to domestic and industrial activities on the Plateau. These materials have effects on crop production in this zone. The present research, under laboratory conditions, aimed to evaluate the effect of three concentrations (25, 35 and 50 µM L-1 of cadmium (Cd and chromium (Cr on imbibition, seed germination and root elongation in lettuce (Lactuca sativa var. Batavia, Swiss chard (Beta vulgaris var. cicla "White Ribbed", and spinach (Spinacia oleracea Hib. 424, three species widely cultivated on the Plateau. The three species used for evaluation showed a differential susceptibility response to Cd and Cr. In lettuce, fresh weight increase (imbibition was lower with all Cd concentrations at the last day of observation and at 25 µM L-1 of Cd in Swiss chard. Cadmium reduced seed germination by up to 46%, 97% and 8% in Swiss chard, lettuce and spinach, respectively. Also, root elongation decreased in Cd treatments by up to 57%, 89% and 56%, for Swiss chard, lettuce and spinach, respectively. Chromium, which showed fewer negative effects, decreased germination by up to 29% in Swiss chard, 6% in lettuce and 34% in spinach, as compared to the control

  9. Distribution and population development of Nasonovia ribisnigri (Homoptera: Aphididae) in iceberg lettuce.

    Science.gov (United States)

    Liu, Yong-Biao

    2004-06-01

    A field study was conducted to determine the distribution and development of aphid Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae) populations in iceberg lettuce, Lactuca sativa L. 'Salinas'. Lettuce plants were transplanted and caged individually in the field and inoculated with apterous N. ribisnigri at 0, 1, 2, 3, and 4 wk after transplanting in spring and fall 2002. Plants were harvested 15-50 d after inoculations; numbers of alates and apterous N. ribisnigri were counted or estimated on each leaf for each plant. Inoculations during all 5 wk of plant development resulted in successful colonization of lettuce heads. Results indicated that head formation did not reduce the risk of colonization by N. ribisnigri to iceberg lettuce; plants were susceptible to colonization by N. ribisnigri throughout their development. For later inoculations, N. ribisnigri populations were relatively smaller, and aphids were found mostly within the heads. For earlier inoculations, N. ribisnigri populations were larger, and within-plant distributions shifted toward frame leaves. The shift of population distributions toward frame leaves correlated significantly with increases in N. ribisnigri population density. For most inoculations, more aphids were present on wrapper leaves than on other leaves. The proportion of alates did not vary significantly with population density. Population development of N ribisnigri also correlated significantly with heat unit accumulation. Yellow sticky cards were used to monitor alates in each cage. Catches of N. ribisnigri alates on yellow sticky cards were significantly correlated with total numbers of alates as well as with total population sizes on individual lettuce plants.

  10. Genetics of resistance against lettuce downy mildew

    Science.gov (United States)

    Lettuce (Lactuca sativa) is one of the most valuable vegetable crops in the U.S. Downy mildew (DM), caused by Bremia lactucae, is the most important foliar disease of lettuce worldwide, which decreases the quality of the marketable portion of the crop. The use of resistant varieties carrying dominan...

  11. Sustainable lettuce: Adaptability to uncertain production conditions

    Science.gov (United States)

    Lettuce is a popular and widely consumed leafy vegetable. California and Arizona annually produce more than 250,000 acres of iceberg, romaine, leaf, and specialty types of lettuce, supplying more than 95% of the U.S market as well as exports to Canada and other countries. These states have dominat...

  12. Concentration of phenolic compounds is increased in lettuce grown under high light intensity and elevated CO2.

    Science.gov (United States)

    Pérez-López, Usue; Sgherri, Cristina; Miranda-Apodaca, Jon; Micaelli, Francesco; Lacuesta, Maite; Mena-Petite, Amaia; Quartacci, Mike Frank; Muñoz-Rueda, Alberto

    2018-02-01

    The present study was focused on lettuce, a widely consumed leafy vegetable for the large number of healthy phenolic compounds. Two differently-pigmented lettuce cultivars, i.e. an acyanic-green leaf cv. and an anthocyanic-red one, were grown under high light intensity or elevated CO 2 or both in order to evaluate how environmental conditions may affect the production of secondary phenolic metabolites and, thus, lettuce quality. Mild light stress imposed for a short time under ambient or elevated CO 2 concentration increased phenolics compounds as well as antioxidant capacity in both lettuce cvs, indicating how the cultivation practice could enhance the health-promoting benefits of lettuce. The phenolic profile depended on pigmentation and the anthocyanic-red cv. always maintained a higher phenolic amount as well as antioxidant capacity than the acyanic-green one. In particular, quercetin, quercetin-3-O-glucuronide, kaempferol, quercitrin and rutin accumulated under high light or high CO 2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO 2 . In both cvs total free and conjugated phenolic acids maintained higher values under all altered environmental conditions, whereas luteolin reached significant amounts when both stresses were administered together, indicating, in this last case, that the enzymatic regulation of the flavonoid synthesis could be differently affected, the synthesis of flavones being favored. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Danish apple cultivars

    DEFF Research Database (Denmark)

    Larsen, Bjarne; Pedersen, Carsten; Ørgaard, Marian

    2017-01-01

    Abstract We made a genetic analysis of about 500 apple cultivars, which either originate from Denmark or have been of greater importance in Denmark. To study the diversity and parentage among the cultivars, 15 SSR markers were used. A new PCR-based protocol for identification of S-alleles was dev......Abstract We made a genetic analysis of about 500 apple cultivars, which either originate from Denmark or have been of greater importance in Denmark. To study the diversity and parentage among the cultivars, 15 SSR markers were used. A new PCR-based protocol for identification of S...

  14. Resistance to lettuce aphid (Nasonovia ribisnigri) biotype 0 in wild lettuce accessions PI 491093 and PI 274378

    Science.gov (United States)

    Lettuce aphid, Nasonovia ribisnigri Mosley (Homoptera : Aphididae), is a major insect pest of lettuce, Lactuca sativa L, in many commercial lettuce productions areas around the world. Resistance to lettuce aphid was first reported in Lactuca virosa L. accession IVT 280 and characterized as complete,...

  15. Weather variability influences color and phenolic content of pigmented baby leaf lettuces throughout the season.

    Science.gov (United States)

    Marin, Alicia; Ferreres, Federico; Barberá, Gonzalo G; Gil, María I

    2015-02-18

    The lack of consistency in homogeneous color throughout the season of pigmented baby leaf lettuce is a problem for growers because of the rejection of the product and consequently the economic loss. Changes in color as well as individual and total phenolic composition and content as a response to the climatic variables were studied following the analysis of three pigmented baby leaf lettuces over 16 consecutive weeks from February to May, which corresponded to the most important production season in winter in Europe. Color and phenolic content were significantly (P ≤ 0.001) affected by cultivar, harvest week, and climatic variables that occurred in the last week before harvest. Radiation and temperature showed positive correlations with the content of phenolic acids and flavonoids that increased in all three cultivars as the season progressed. Cyanidin-3-O-(6''-O-malonyl)-glucoside content showed positive correlations with temperature and radiation but only in Batavia cultivars whereas in red oak leaf the correlation was with cold temperatures. Regarding hue angle, a positive correlation was shown with the number of hours at temperatures lower than 7 °C. A relationship between hue angle and the content of anthocyanins was not possible to establish. These results suggest that the colorimetric measurement of color cannot be used as a good indicator of anthocyanin accumulation because other pigments such as chlorophylls and carotenoids may contribute as well to the leaf color of pigmented lettuce. This study provides information about the impact of genotype and environment interactions on the biosynthesis of phenolic compounds to explain the variability in the leaf color and product appearance.

  16. Exogenous Glycine Nitrogen Enhances Accumulation of Glycosylated Flavonoids and Antioxidant Activity in Lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Xiao Yang

    2017-12-01

    Full Text Available Glycine, the simplest amino acid in nature and one of the most abundant free amino acids in soil, is regarded as a model nutrient in organic nitrogen studies. To date, many studies have focused on the uptake, metabolism and distribution of organic nitrogen in plants, but few have investigated the nutritional performance of plants supplied with organic nitrogen. Lettuce (Lactuca sativa L., one of the most widely consumed leafy vegetables worldwide, is a significant source of antioxidants and bioactive compounds such as polyphenols, ascorbic acid and tocopherols. In this study, two lettuce cultivars, Shenxuan 1 and Lollo Rossa, were hydroponically cultured in media containing 4.5, 9, or 18 mM glycine or 9 mM nitrate (control for 4 weeks, and the levels of health-promoting compounds and antioxidant activity of the lettuce leaf extracts were evaluated. Glycine significantly reduced fresh weight compared to control lettuce, while 9 mM glycine significantly increased fresh weight compared to 4.5 or 18 mM glycine. Compared to controls, glycine (18 mM for Shenxuan 1; 9 mM for Lollo Rossa significantly increased the levels of most antioxidants (including total polyphenols, α-tocopherol and antioxidant activity, suggesting appropriate glycine supply promotes antioxidant accumulation and activity. Glycine induced most glycosylated quercetin derivatives and luteolin derivatives detected and decreased some phenolic acids compared to nitrate treatment. This study indicates exogenous glycine supplementation could be used strategically to promote the accumulation of health-promoting compounds and antioxidant activity of hydroponically grown lettuce, which could potentially improve human nutrition.

  17. Exogenous Glycine Nitrogen Enhances Accumulation of Glycosylated Flavonoids and Antioxidant Activity in Lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Yang, Xiao; Cui, Xiaoxian; Zhao, Li; Guo, Doudou; Feng, Lei; Wei, Shiwei; Zhao, Chao; Huang, Danfeng

    2017-01-01

    Glycine, the simplest amino acid in nature and one of the most abundant free amino acids in soil, is regarded as a model nutrient in organic nitrogen studies. To date, many studies have focused on the uptake, metabolism and distribution of organic nitrogen in plants, but few have investigated the nutritional performance of plants supplied with organic nitrogen. Lettuce ( Lactuca sativa L.), one of the most widely consumed leafy vegetables worldwide, is a significant source of antioxidants and bioactive compounds such as polyphenols, ascorbic acid and tocopherols. In this study, two lettuce cultivars, Shenxuan 1 and Lollo Rossa, were hydroponically cultured in media containing 4.5, 9, or 18 mM glycine or 9 mM nitrate (control) for 4 weeks, and the levels of health-promoting compounds and antioxidant activity of the lettuce leaf extracts were evaluated. Glycine significantly reduced fresh weight compared to control lettuce, while 9 mM glycine significantly increased fresh weight compared to 4.5 or 18 mM glycine. Compared to controls, glycine (18 mM for Shenxuan 1; 9 mM for Lollo Rossa) significantly increased the levels of most antioxidants (including total polyphenols, α-tocopherol) and antioxidant activity, suggesting appropriate glycine supply promotes antioxidant accumulation and activity. Glycine induced most glycosylated quercetin derivatives and luteolin derivatives detected and decreased some phenolic acids compared to nitrate treatment. This study indicates exogenous glycine supplementation could be used strategically to promote the accumulation of health-promoting compounds and antioxidant activity of hydroponically grown lettuce, which could potentially improve human nutrition.

  18. Genetic Variation for Thermotolerance in Lettuce Seed Germination Is Associated with Temperature-Sensitive Regulation of ETHYLENE RESPONSE FACTOR1 (ERF1)1[OPEN

    Science.gov (United States)

    O’Brien, Laurel K.; Truco, Maria Jose; Huo, Heqiang; Sideman, Rebecca; Hayes, Ryan; Michelmore, Richard W.

    2016-01-01

    Seeds of most lettuce (Lactuca sativa) cultivars are susceptible to thermoinhibition, or failure to germinate at temperatures above approximately 28°C, creating problems for crop establishment in the field. Identifying genes controlling thermoinhibition would enable the development of cultivars lacking this trait and, therefore, being less sensitive to high temperatures during planting. Seeds of a primitive accession (PI251246) of lettuce exhibited high-temperature germination capacity up to 33°C. Screening a recombinant inbred line population developed from PI215246 and cv Salinas identified a major quantitative trait locus (Htg9.1) from PI251246 associated with the high-temperature germination phenotype. Further genetic analyses discovered a tight linkage of the Htg9.1 phenotype with a specific DNA marker (NM4182) located on a single genomic sequence scaffold. Expression analyses of the 44 genes encoded in this genomic region revealed that only a homolog of Arabidopsis (Arabidopsis thaliana) ETHYLENE RESPONSE FACTOR1 (termed LsERF1) was differentially expressed between PI251246 and cv Salinas seeds imbibed at high temperature (30°C). LsERF1 belongs to a large family of transcription factors associated with the ethylene-signaling pathway. Physiological assays of ethylene synthesis, response, and action in parental and near-isogenic Htg9.1 genotypes strongly implicate LsERF1 as the gene responsible for the Htg9.1 phenotype, consistent with the established role for ethylene in germination thermotolerance of Compositae seeds. Expression analyses of genes associated with the abscisic acid and gibberellin biosynthetic pathways and results of biosynthetic inhibitor and hormone response experiments also support the hypothesis that differential regulation of LsERF1 expression in PI251246 seeds elevates their upper temperature limit for germination through interactions among pathways regulated by these hormones. Our results support a model in which LsERF1 acts through

  19. sativa L.) Cultivars

    African Journals Online (AJOL)

    Abstract. Ten rice cultivars from the International Rice Germplasm Centre originating from Bangladesh were analysedfor the~r genetics of resistance to bacterial blight. The test cultivars were selected on the basis of their high level ofresistance to races IV & VI ofXanthomonas oryzae pv. oryzae. The mode ofinheri- tance was ...

  20. Influence of nitrogen and phosphorus sources on mycorrhizal lettuces under organic farming

    Science.gov (United States)

    Scotti, Riccardo; Seguel, Alex; Cornejo, Pablo; Rao, Maria A.; Borie, Fernando

    2010-05-01

    Arbuscular mycorrhizal fungi (AMF) develop symbiotic associations with plants roots. These associations are very common in the natural environment and can provide a range of benefits to the host plant. AMF improve nutrition, enhance resistance to soil-borne pests and disease, increase resistance to drought and tolerance to heavy metals, and contribute to a better soil structure. However, agricultural intensive managements, such as the use of mineral fertilizes, pesticides, mouldboard tillage, monocultures and use of non-mycorrhizal crops, are detrimental to AMF. As a consequence, agroecosystems are impoverished in AMF and may not provide the full range of benefits to the crop. Organic farming systems may be less unfavourable to AMF because they exclude the use of water-soluble fertilisers and most pesticides, and generally they plan diverse crop rotations. The AMF develop the most common type of symbiosis in nature: about 90% of the plants are mycorrhizal and many agricultural crops are mycorrhizal. One of more mycorrhizal crops is lettuce, that is very widespread in intensive agricultural under greenhouse. Therefore, cultivated lettuce is know to be responsive to mycorrhizal colonization which can reach 80% of root length and contribute to phosphorus and nitrogen absorption by this plant specie. For this work four different lettuce cultivars (Romana, Milanesa, Grande Lagos and Escarola) were used to study mycorrhization under organic agricultural system, supplying compost from agricultural waste (1 kg m-2) as background fertilization for all plots, red guano as phosphorus source (75 U ha-1 and 150 U ha-1 of P2O5), lupine flour as nitrogen source (75 and 150 U/ha of N) and a combination of both. Lettuce plants were cultivated under greenhouse and after two months of growing, plants were harvested and dried and fresh weight of lettuce roots and shoots were evaluated. The number of spores, percentage of colonization, total mycelium and glomalin content were also

  1. Phenolic composition and related antioxidant properties in differently colored lettuces: a study by electron paramagnetic resonance (EPR) kinetics.

    Science.gov (United States)

    Pérez-López, Usue; Pinzino, Calogero; Quartacci, Mike Frank; Ranieri, Annamaria; Sgherri, Cristina

    2014-12-10

    Differently colored lettuce (Lactuca sativa L.) cultivars (green, green/red, and red) were studied to correlate their phenolic composition with their antioxidant kinetic behavior. Electron paramagnetic resonance (EPR) was employed to monitor decay kinetics of 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)), which allowed the identification of three differently paced antioxidants. The results showed that as long as lettuce had higher red pigmentation, the hydrophilic antioxidant capacity increased together with the contents in free and conjugated phenolic acids, free and conjugated flavonoids, and anthocyanins. EPR allowed the identification of slow-rate antioxidants in green and green/red cultivars, intermediate-rate antioxidants in green, green/red, and red cultivars, and fast-rate antioxidants in green/red and red cultivars. At present, the different kinetic behaviors cannot be attributed to a specific antioxidant, but it is suggested that the flavonoid quercetin accounted for the majority of the intermediate-rate antioxidants, whereas the anthocyanins accounted for the majority of the fast-rate antioxidants.

  2. Precut prepackaged lettuce: a risk for listeriosis?

    Science.gov (United States)

    Hanning, Irene B; Johnson, Michael G; Ricke, Steven C

    2008-12-01

    The most recent outbreaks of listeriosis have been traced back to contaminated ready-to-eat (RTE) poultry and meat products. However, Listeria monocytogenes can be isolated from every food group, including fresh vegetables. This review is focused on one of the most popular RTE vegetable products, precut prepackaged lettuce. The available literature concerning Listeria contamination of vegetables is reviewed, and possible reasons why no recent outbreaks or sporadic cases of listeriosis due to contaminated precut prepackaged lettuce are explored.

  3. Cyclobutyl pyrimidine dimer accumulation in relation to UV-B sensitivity in mung bean cultivars

    International Nuclear Information System (INIS)

    He Junmin; Wang Ruibin; Meng Zhaoni

    2006-01-01

    The purpose of the experiment is to reveal the relationship between cyclobutyl pyrimidine dimers (CPDs) accumulation and UV-B sensitivity in mung bean cultivars. Two mung bean cultivars (Phaseolus raditus L. cv. Qindou -2 0 and Zhonglü -1 ) were grown in greenhouse with treatment or without treatment of UV-B radiation (0.4 W * m -2 ) for four days. The UV-B-induced CPDs in mung bean DNA were quantified by enzyme-linked immunosorbent assay (ELISA) with specific monoclonal antibody and the relationship between CPDs accumulation and the UV-B sensitivity of mung bean seedlings were discussed. The UV-B-induced inhibition of the biomass and net photosynthetic rate of the primary leaves of cultivar Zhonglü -1 were respectively lower than that of cultivar Qindou -2 0, so that the cultivar Zhonglü -1 was more tolerant to UV-B than the cultivar Qindou -2 0. Meanwhile, the cultivar Zhonglü -1 had lower CPD accumulation and susceptibility to CPD induction, higher photorepair capacity and same dark repair capacity as compared with the cultivar Qindou -2 0. Different UV-B sensitivities between two mung bean cultivars may be mainly caused by the differences in CPD accumulation, which are caused by the different susceptibility to CPD induction and the different photorepair capacities. In addition, the different susceptibility to CPD induction between two mung bean cultivars is related to the different levels of UV-absorbing compounds

  4. Positive effects of temperature and growth conditions on enzymatic and antioxidant status in lettuce plants.

    Science.gov (United States)

    Boo, Hee-Ock; Heo, Buk-Gu; Gorinstein, Shela; Chon, Sang-Uk

    2011-10-01

    The contents of two bioactive compounds (polyphenols and flavonoids) and their antioxidant and enzyme activities were determined in the leaves of six lettuce (Latuca sativa L.) cultivars subjected to 4 different day/night temperatures for 6 weeks. The total polyphenol and anthocyanin contents and the corresponding antioxidant activities were the highest at 13/10°C and 20/13°C, followed by 25/20°C and 30/25°C. The enzymatic activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were also the highest at low day/night temperatures, but the peroxidase (POD) activity was decreased at low day/night temperatures and increased at high day/night temperatures. The most significant positive correlation existed between anthocyanin content and PPO activity, total polyphenols and their antioxidant activities. The results showed that at relatively low temperatures, lettuce plants have a high antioxidant and enzymatic status. These results provide additional information for the lettuce growers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. Allelopathic activity of medicinal plant essential oils on seed germination and vigor of lettuce achenes

    Directory of Open Access Journals (Sweden)

    Cíntia Alvarenga Santos Fraga de Miranda

    2015-07-01

    Full Text Available In recent years, essential oils have gained commercial interest in the agricultural area, mainly for their allelopathic, insecticidal, antifungal, antimicrobial and antioxidant properties, and, also for their natural compounds, which have generally displayed low toxicity, relatively low cost and rapid degradation in the environment. Medicinal plants have emerged as potential suppliers of essential oils because of their ethnopharmacological utility. The aim of this study was to evaluate the allelopathic potential of essential oils extracted from fresh leaves of lemon grass (Cymbopogon citratus, wild basil (Ocimum gratissimum L. and sweet basil (Ocimum basilicum L. with regard to their major constituents (citral, eugenol and cineol, respectively in different application forms (direct contact and the effect of volatile constituents on the germination and vigor of lettuce seeds (cultivar Regina SF 3500. The effects of the oils and their major components were evaluated with regard to the variables: first germination count, total germination, GVI (germination velocity index, seedling dry weight and average lengths of shoots and lettuce roots. The essential oils from lemon grass and basil displayed allelopathic potentials on seed germination and vigor of lettuce achenes that can be assigned to their respective major constituents citral and eugenol. On the other hand, the allelopathic effect of the essential oil from basil was a consequence of the combined effect of all the components, regardless the application method.

  6. Phosphorus levels in soil and lettuce production due to phosphorus fertilization

    Directory of Open Access Journals (Sweden)

    José Ricardo Mantovani

    2014-09-01

    Full Text Available The leafy vegetables are considered nutrient-demanding, but are scarce in the literature works about phosphorus fertilization. This study aimed to evaluate the effect of phosphate on the production of lettuce, content and amount of P accumulated in leaf plants, and to relate levels of P in the clayey soil with plant production. The experiment was conducted in a greenhouse in pots in a randomized block design with ten treatments and four replications. The treatments were made up of P, corresponding to 0, 50, 100, 150, 200, 300, 400, 500, 600 and 700 mg dm-3, as triple superphosphate powder. Portions of 6 dm3 of the clay soil (420 g kg-1 clay received lime, aimed at raising the V % soil to 70 %, equivalent to 20 t ha-1 of cattle manure, and the phosphate fertilizer according to the treatments, remaining incubated for about 30 days. At the end of incubation, each pot received a change of lettuce cultivar Verônica. The plant harvesting was performed 39 days after transplanting the seedlings. O P gave large increases in growth and production of lettuce, and culture responded positively to the application of high doses of the nutrient. A dose of 350 mg dm-3, equivalent to 800 kg ha-1 P2O5, was the most suitable for growing lettuce in the clay soil. In this work conditions, the phosphorus fertilizations it was necessary when the P-Mehlich contents in the clay soil were less than 75 mg dm-3.

  7. Apple cultivars resistant to scab (Venturia inaequalis (Cke. Aderh. Part II. Winterhardiness of apple cultivars

    Directory of Open Access Journals (Sweden)

    Zbigniew Borecki

    2013-12-01

    Full Text Available The severe winter which occurred in Poland in 1986-1987 damaged the most part of scab resistant apple cultivars and selected apple hybrids. Cold hardiness studied in 1987 and 1988 showed significant differences in degree of frost injury on stem, branches, twigs and buds of apple trees. Two scab-resistance cultivars, namely Florina and Sir Prize, as well as two check culuvars, Idared and Golden Delicious, were killed by frost. Strong damages were noted in cultivars: Prima, Primula, and Priam. Lower susceptibility showed: Jonafree, Gavin, Liberty Sister and three hybrids selected from crosses of Bankroft with scab-resistant Primula. Relatively frost resistant was Novamac and three hybrids of U-breeding line: U-1101 and U-50, originated from crosses of polish culrivar Fantazja (McIntosh x Linda with Primula, Highest resistance to frost showed cultivars: Freedom. Liberty. new polish cultivar Witos (Fantazja x Primula and three hybrids: U-337, U-237 and U-1098. During the 1987 and 1988 seasons severe infection of apple trees by numerous fungi was noted. Twelve species of isolated fungi were identified as pathogens of apple trees bark and wood.

  8. Reaction of rice cultivars to a virulent Rice Yellow Mottle Virus strain ...

    African Journals Online (AJOL)

    Isolates of RYMV were collected from three “hot-spots” in Uganda (Lira, Luweero and Iganga). The isolate from Iganga was most virulent on RYMV susceptible cultivar (IR64), and thus used to constitute study treatment evaluated in the study. Cultivars were potted and raised in a screenhouse experiment arranged in a ...

  9. Genetic investigation of the nonhost resistance of wild lettuce, Lactuca saligna, to lettuce downy mildew, Bremia lactucae

    NARCIS (Netherlands)

    Boer, den E.

    2014-01-01

    Abstract

    Downy mildew (Bremia lactucae) in lettuce (Lactuca sativa) is a devastating foliar disease causing high losses in lettuce cultivation. The wild lettuce and nonhost species, Lactuca saligna, is absolute resistant to downy mildew and

  10. Nutrient absorption and response of lettuce to phosphorus fertilization

    Directory of Open Access Journals (Sweden)

    Antonio Ismael Inácio Cardoso

    2012-09-01

    Full Text Available The objective of this study was to evaluate the response of lettuce (cultivar Verônica to different levels of phosphorus fertilization. The experiment was conducted from 25/09/2003 (sowing to 03/12/2003 (harvesting at the Fazenda Experimental São Manuel, UNESP/FCA, Botucatu/SP, under protective structures. The experiment was conducted in a randomized block design, with five treatments (0, 200, 400, 600 and 800kg.ha-1 of P2O5, in the form of triple superphosphate and five replications. Plants were grown in 13L plastic pots containing Latossolo Vermelho Distrófico Típico. A quadratic response was observed for the fresh mass of the plant shoots and leaf area, with maximum equivalent levels of 733 and 756kg.ha-1 of P2O5, respectively, as well as for potassium, calcium, magnesium, sulfur, boron, copper, iron, manganese and zinc accumulation. Linear increases were observed with the treatments of P2O5 for dry mass of the shoots, leaf number, plant height and nitrogen and phosphorus accumulation.

  11. Sources of Verticillium dahliae affecting lettuce.

    Science.gov (United States)

    Atallah, Zahi K; Maruthachalam, Karunakaran; Subbarao, Krishna V

    2012-11-01

    ABSTRACT Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.

  12. Stimulation of lettuce seed germination by ethylene.

    Science.gov (United States)

    Abeles, F B; Lonski, J

    1969-02-01

    Ethylene increased the germination of freshly imbibed lettuce (Lactuca sativa L. var. Grand Rapids) seeds. Seeds receiving either red or far-red light or darkness all showed a positive response to the gas. However, ethylene was apparently without effect on dormant seeds, those which failed to germinate after an initial red or far-red treatment. Carbon dioxide, which often acts as a competitive inhibitor of ethylene, failed to clearly reverse ethylene-enhanced seed germination. While light doubled ethylene production from the lettuce seeds, its effect was not mediated by the phytochrome system since both red and far-red light had a similar effect.

  13. Evaluation of sugarcane cultivars for resistance to colletotrichum falcatum went

    International Nuclear Information System (INIS)

    Sohail, F.; Qureshi, M.A.

    2004-01-01

    Screening for resistance against Colletotrichum falcatum was performed In 96 test lines of sugarcane by artificially inoculation method under field conditions for two consecutive years (1998-99). Out of these 96 cultivars, 43 were graded intermediately resistant and 53 intermediately susceptible on the basis of 0-9 scale. (author)

  14. Response of common bean ( Phaseolus vulgaris L.) cultivars to ...

    African Journals Online (AJOL)

    Yield losses in common bean (Phaseolus vulgaris L.) may occur due to boron (B) deficiency when the susceptible cultivars are grown in calcareous boron deficient soils. The study was therefore aimed at investigating the effects of three B doses: control (0.0 kg ha-1), soil application (3.0 kg ha-1) and foliar fertilization (0.3 kg ...

  15. MGS Esmeralda: new large seed mungbean cultivar MGS Esmeralda: nova cultivar de mungo-verde de sementes grandes

    Directory of Open Access Journals (Sweden)

    Rogério Faria Vieira

    2008-06-01

    Full Text Available Mungbean cultivar MGS Esmeralda was developed by Asian Vegetable Research and Development Center (Shanhua, Taiwan, as a result of crossing between the lines VC 1973A and VC 2768A. In ten trials conducted in the State of Minas Gerais, Brazil, it produced 13.5% more grains than 'Ouro Verde MG-2' (control cultivar, and its highest yield was 2,550 kg ha-1. The cultivar MGS Esmeralda is more susceptible to lodging, and its pods mature more uniformly than Ouro Verde MG-2 pods. One hundred-seed mass of 'MGS Esmeralda' ranged between 5.5 and 6.8 g. Both cultivars are susceptible to powdery mildew and cercospora leaf spot.A cultivar de mungo-verde MGS Esmeralda foi criada pelo Asian Vegetable Research and Development Center, localizado em Shanhua, Formosa. Ela é resultado do cruzamento entre as linhagens VC 1973A e VC 2768A. Em dez ensaios conduzidos em Minas Gerais, ela produziu 13,5% mais grãos do que a cultivar Ouro Verde MG-2 (testemunha, e sua produtividade mais alta foi 2.550 kg ha-1. A cultivar MGS Esmeralda é mais suscetível ao acamamento do que a Ouro Verde MG-2, mas suas vagens amadurecem mais uniformemente. A massa de 100 grãos da 'MGS Esmeralda' varia de 5,5 a 6,8 g. Ambas as cultivares são suscetíveis ao oídio e à cercosporiose.

  16. Pessegueiro: cultivar BRS kampai

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Bassols Raseira

    2010-12-01

    Full Text Available RESUMO O programa de Melhoramento Genético de Pessegueiros da Embrapa Clima Temperado tem, entre seus objetivos, a obtenção de cultivares produtoras de frutas para consumo in natura, com características que satisfaçam às exigências dos consumidores. Alguns dos grandes centros consumidores, como é o caso de São Paulo e Curitiba, preferem pêssegos de polpa branca e sabor doce. A cultivar BRS Kampai, obtida de um cruzamento entre 'Chimarrita' e 'Flordaprince', alia a baixa necessidade em frio, o que é uma vantagem em regiões subtropicais, à boa aparência, com sabor superior a qualquer um dos parentais. A colheita dos frutos desta cultivar inicia-se geralmente, em meados de novembro, em Pelotas-RS (em Atibaia, São Paulo, inicia-se na segunda quinzena de outubro, poucos dias antes das cultivares Rubimel (polpa amarela e Premier (polpa branca, sendo ótima substituta para esta última.

  17. Consórcios alface-cenoura e alface-rabanete sob manejo orgânico Intercropping of lettuce-carrot and lettuce-radish under organic management

    Directory of Open Access Journals (Sweden)

    Ailena Sudo Salgado

    2006-07-01

    Full Text Available Dois experimentos foram conduzidos, por dois anos consecutivos, em Seropédica, RJ, com o objetivo de avaliar o desempenho agronômico dos consórcios das cultivares de alface 'Regina 71' (lisa e 'Verônica' (crespa com cenoura 'Brasília' e rabanete 'Híbrido nº 19', sob manejo orgânico, assim como determinar as quantidades de macronutrientes exportadas. O delineamento experimental usado foi o de blocos ao acaso, com quatro repetições. No primeiro experimento, os tratamentos consistiram de alface crespa em consórcio com cenoura, alface crespa em consórcio com rabanete e os cultivos solteiros. No segundo experimento, usou-se alface lisa em lugar da crespa. Nos consórcios entre cenoura e alface crespa ou lisa, foram observados índices de uso eficiente da terra, superiores a 1,60. Nos consórcios de rabanete com alface, crespa ou lisa, esses índices foram de 1,54 e 1,27, respectivamente. As quantidades de nutrientes extraídas do sistema pelos produtos colhidos foram inferiores aos aportes efetuados, evidenciando a viabilidade de qualquer dos consórcios avaliados.Two experiments were carried out, in two consecutive years, at Seropédica, RJ, Brazil, aiming to evaluate the agronomic performance of intercropping of lettuce cvs. Regina 71 (smooth leaf and Verônica (crisp leaf with carrot (cv. Brasília and radish (cv. Hybrid number 19, under organic management. The amount of nutrients exported from the system by harvesting was also evaluated. The experimental design used was of completely randomized blocks, with four replications. In the first experiment, treatments consisted of lettuce with crisp leaves intercropped with carrot, lettuce with crisp leaves intercropped with radish and sole crops. In the second experiment, lettuce with smooth leaves was used instead of lettuce with crisp leaves. Intercropping of carrot and lettuce, with crisp or smooth leaf, presented land equivalent ratios higher than 1.60. Intercropping of radish and

  18. Ladybugs and Lettuce Leaves. Teachers' Manual.

    Science.gov (United States)

    Barnes, Tracy; And Others

    This is a guide for use with "Ladybugs and Lettuce Leaves" activity cards which are activities for elementary school students (grades 4 to 6) focusing on gardening. It includes educational objectives for each topic as well as lists of vocabulary words, comments, questions for discussion, additional activities, and resources. An interdisciplinary…

  19. Sensory analysis of calcium-biofortified lettuce

    Science.gov (United States)

    Vegetables represent an attractive means of providing increased calcium nutrition to the public. In this study, it was demonstrated that lettuce expressing the deregulated Arabidopsis H(+)/Ca(2+) transporter sCAX1 (cation exchanger 1) contained 25-32% more calcium than controls. These biofortified l...

  20. Overexpression of homogentisate phytyltransferase in lettuce results ...

    African Journals Online (AJOL)

    In this study, HPT gene isolated from Lactuca sativa L. (LsHPT) was transferred into L. sativa (lettuce) via Agrobacterium-mediated method and 15 transgenic plants were obtained. The expression of LsHPT gene and the total content of and -tocopherol in transgenic plants were increased up to 4 and 2.61 folds, respectively, ...

  1. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls.

    Science.gov (United States)

    Becker, Christine; Urlić, Branimir; Jukić Špika, Maja; Kläring, Hans-Peter; Krumbein, Angelika; Baldermann, Susanne; Goreta Ban, Smiljana; Perica, Slavko; Schwarz, Dietmar

    2015-01-01

    Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants' response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM), either in full or reduced (-50%) radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis.

  2. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls

    Science.gov (United States)

    Becker, Christine; Urlić, Branimir; Jukić Špika, Maja; Kläring, Hans-Peter; Krumbein, Angelika; Baldermann, Susanne; Goreta Ban, Smiljana; Perica, Slavko; Schwarz, Dietmar

    2015-01-01

    Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants’ response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM), either in full or reduced (-50%) radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis. PMID:26569488

  3. Nitrogen Limited Red and Green Leaf Lettuce Accumulate Flavonoid Glycosides, Caffeic Acid Derivatives, and Sucrose while Losing Chlorophylls, Β-Carotene and Xanthophylls.

    Directory of Open Access Journals (Sweden)

    Christine Becker

    Full Text Available Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants' response to low nitrogen concentration can interact with other factors, for example radiation intensity. We cultivated red and green leaf lettuce hydroponically in a Mediterranean greenhouse, supplying three different levels of nitrogen (12 mM, 3 mM, 0.75 mM, either in full or reduced (-50% radiation intensity. In both red and green lettuce, we found clear effects of the nitrogen treatments on growth characteristics, phenolic and photosynthetic compounds, nitrogen, nitrate and carbon concentration of the plants. Interestingly, the concentrations of all main flavonoid glycosides, caffeic acid derivatives, and sucrose increased with decreasing nitrogen concentration, whereas those of chlorophylls, β-carotene, neoxanthin, lactucaxanthin, all trans- and cis-violaxanthin decreased. The constitutive concentrations of polyphenols were lower in the green cultivar, but their relative increase was more pronounced than in the red cultivar. The constitutive concentrations of chlorophylls, β-carotene, neoxanthin, all trans- and cis-violaxanthin were similar in red and green lettuce and with decreasing nitrogen concentration they declined to a similar extent in both cultivars. We only detected little influence of the radiation treatments, e.g. on anthocyanin concentration, and hardly any interaction between radiation and nitrogen concentration. Our results imply a greater physiological plasticity of green compared to the red lettuce regarding its phenolic compounds. They support the photoprotection theory regarding anthocyanins as well as the theory that the deamination activity of phenylalanine ammonia-lyase drives phenylpropanoid synthesis.

  4. Evaluation of the Incidence and Severity of Olive Leaf Spot caused by Spilocaea oleaginain different olive cultivars in Palestine

    Directory of Open Access Journals (Sweden)

    Ruba Abuamsha

    2013-12-01

    Full Text Available Twelve olive (Olea europaea L. cultivars including Nabali Baladi, Nabali Mohassan, Santa Augustino, Nasohi Jaba`a 1, Nasohi Jaba`a 2, Yunani, Talmasani, Chemlali, Arbequino, Frantoio, Coca and Barouni, were sampled for their susceptibility to Spilocaea oleagina the causal agent for Olive leaf spot (OLS disease on olive trees in Palestine. Investigations were carried out to measure the incidence and severity of the disease at Qabatyia station in Jenin district area Susceptible olive cultivars grown commercially in Palestine include Arbequino, Frantoio and ?Barouni’.The “Nabali” is the most dominant and highly susceptible olive cultivar grown in Palestine. Disease incidence varied greatly among the cultivars F=59.4, df=11, 251, p?0.0001 and was correlated with the severity (y = 0.42x + 9.3, P ? 0.0001, R² = 0.84, y = disease severity and x = disease incidence. Disease severity also varied among different cultivars F=13.9, df=11, 251, p?0.0001. Nabali Mohassan was the most affected susceptible while Barouni was most resistant. Progress of disease severity over time fit the logistic function for all cultivars except for highly susceptible cultivars F=1.56, df=6, 83, p?0.169. The assessment method may be useful to screen olive cultivars for OLS resistance in Palestine.

  5. Evaluation of sanitary quality of lettuce (Lactuca sativa, L. irrigated with reused water in comparison with commercialized lettuce

    Directory of Open Access Journals (Sweden)

    Claudinei Fonseca Souza

    2011-08-01

    Full Text Available Inadequate use of water resources reduces their availability and therefore, research focused on their reutilization is required. This work evaluated the sanitary quality of lettuce irrigated with reused water in comparison with samples of lettuce commercialized in Taubaté (SP market. An experiment was developed in a greenhouse with three beds of lettuce irrigated with reused water and three beds of lettuce irrigated with urban water supply. After lettuce biological cycle had been completed, lettuce samples were collected from the beds (irrigated and non-irrigated with reused water and from samples of lettuce commercialized in the city market that were analyzed in the laboratory. The analyses were done using the multiple tubes methodology. The results showed that the samples from lettuce irrigated with urban water supply were not contaminated by either total or thermotolerant coliforms while samples of irrigated lettuce with reused water were contaminated by total coliforms. Samples from commercialized lettuce were contaminated by both kinds of coliforms. Results indicated that the application of reused water for agricultural purposes should occur only after carefully treatment to allow a safe use and to contribute to the water use sustainability.

  6. RESISTANCE OF SOME GROUNDNUT CULTIVARS TO SOYBEAN POD BORER, ETIELLA ZINCKENELLA TREIT. (LEPIDOPTERA: PYRALIDAE

    Directory of Open Access Journals (Sweden)

    Dwinardi Apriyanto, Edi Gunawan, dan Tri Sunardi .

    2011-11-01

    Full Text Available Resistance of some groundnut cultivars to soybean pod borer, Etiella zinckenella Treit. (Lepidoptera: Pyralidae.  Five groundnut cultivars: Badak, Panther, Sima, Gajah, and Simpai, were grown in field in June-August, 2006 to determine their resistance/susceptibility to Etiella zinckenella Treit.  Two local cultivars (big and small seeds were included as comparison (controls. All cultivars were grown in experimental plots arranged in a randomized complete block design (RCBD, replicated three times. The incidence of soybean pod borer and damaged pods were observed at 9, 11, 13 weeks after sowing (WAS at 10 sample plants taken randomly from each plot. All cultivars were harvested at 13 WAS. Number of damaged pods was counted and percentages per plant were calculated. Larvae observed inside pod or in the soil were counted and collected. The seed yield per plant and weight of 100 seeds from 100 sample plants taken randomly at harvest were weighted to nearest gram at 10% water content. Pod toughness (hardness was measured with penetrometer. Resistance level of each cultivar was determined based on cultivar’s means and overall mean and standard deviation of the percentages of damaged pods. Data were analyzed with analysis of variance (ANOVA and means were separated with DMRT. The result revealed that mean percentages of damaged pod differed significantly between cultivars. Seed yield of cultivar Panther, Sima and Badak were significantly higher than those of the other two and local cultivars. Cultivar Panther was categorized as resistant, cultivar Sima and Badak as moderately resistant, while the others as susceptible. The relative resistance of groundnut cultivar seems, at least in part, to correlate with the structural hardness of pod.

  7. Agronomic efficiency of intercropping tomato and lettuce

    Directory of Open Access Journals (Sweden)

    Arthur B. Cecílio Filho

    2011-09-01

    Full Text Available Four experiments were carried out at the São Paulo State University, Brazil, with the aim of determining the agronomic viability of intercropping tomato and lettuce, under greenhouse conditions. The studied intercropping systems were established by transplanting lettuce at 0, 10, 20 and 30 days after transplanting (DAT tomato and by transplanting tomato at 0, 10, 20 and 30 DAT lettuce. Intercropped tomato and lettuce were evaluated during two seasons and compared to their sole cropping. The experimental design was a randomized complete block with nine treatments. The productivity and the classification of the tomato fruits were not influenced by having lettuce intercropped with it, but lettuce production was lowered when tomato was intercropped with it. The longer the delay in lettuce transplanting, the greater the reduction in its productivity. There was an effect of cropping season on the extent of the agronomic advantage of intercropping over sole cropping. In the first cropping season, intercropping established by transplanting lettuce during the interval between 30 days before up to 20 DAT tomato yielded land use efficiency (LUE indices of 1.63 to 2.22. In the second period, intercropping established with the transplanting of lettuce up to 30 days before tomato yielded LUE indices of 1.57 to 2.05.Quatro experimentos foram conduzidos na Unesp, Brasil, com o objetivo de determinar a viabilidade agronômica de cultivos consorciados de alface e tomate em ambiente protegido. Consórcios estabelecidos por transplantes da alface aos 0, 10, 20 e 30 dias após o transplante (DAT do tomate e de tomate aos 0, 10, 20 e 30 DAT da alface, foram avaliados em duas épocas e comparados às suas monoculturas. Cada experimento foi conduzido em delineamento de blocos ao acaso, com nove tratamentos. Verificou-se que a produtividade do tomate e a classificação dos frutos não foram influenciadas pela alface, mas a produção da alface foi menor em cons

  8. Effect of dim light irradiation on preservation of fresh lettuce

    International Nuclear Information System (INIS)

    Harada, F.; Uchino, T.; Akimoto, K.; Hu, W.

    2001-01-01

    In order to preserve fresh lettuce, the dim light irradiation storage was investigated. Lettuce (Lactuca sativa L.) stored for about 120 hours at 5 or 20 deg C under continuous illumination at 0 (darkness), 1.6, 3.4, 6.5, 13 or 19.7 micro mol/m**-2/s**-1 photosynthetic photon flux. The light compensation point was about 3.4 micro mol/m**-2/s**-1 at 5 deg C, about 19.7 micro mol/m**-2/s**-1 at 20 deg C. Fresh weight of lettuce decreased by promotion of transpiration caused by the dim light. Accordingly the root of lettuce should not be removed, so as to up-take water. The optimum dim light irradiation preserved the chlorophyll content in lettuce leaf or increased it. Therefore it appeared that the dim light irradiation was effective for the fresh lettuce preservation

  9. Weedborne reservoirs and seed transmission of Verticillium dahliae in lettuce

    OpenAIRE

    Vallad, G E; Bhat, R G; Koike, S T; Ryder, E J; Subbarao, K V

    2005-01-01

    The seed transmission of Verticillium dahliae was evaluated in lettuce (Lactuca sativa). Seed collected from lettuce plants infected with V. dahliae were plated with or without surface sterilization on Sorenson's modified NP10 medium. Of the seed plated with or without surface sterilization, 90 and 66 %, respectively, yielded colonies of V. dahliae. The incidence of Verticillium wilt ranged from 55 to 80 % among lettuce plants grown from seed harvested from infected plants. All evaluated isol...

  10. Unravelling the resistance mechanism of lettuce against Nasonovia ribisnigri

    OpenAIRE

    Broeke, ten, C.J.M.

    2013-01-01

    Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically important pest of cultivated lettuce, Lactuca sativa L. Host plant resistance has been used since 1982 to control this aphid species and is mediated by the Nr-gene, originating from wild lettuce Lactuca virosa L. H...

  11. Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce.

    Science.gov (United States)

    Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

    2012-10-01

    The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009-2010 crop cycle. Total bacterial populations averaged between 10(5) and 10(6) per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial 'core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment.

  12. Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce

    Science.gov (United States)

    Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

    2012-01-01

    The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009–2010 crop cycle. Total bacterial populations averaged between 105 and 106 per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial ‘core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment. PMID:22534606

  13. Characterization of lettuce big-vein associated virus and Mirafiori lettuce big-vein virus infecting lettuce in Saudi Arabia.

    Science.gov (United States)

    Umar, M; Amer, M A; Al-Saleh, M A; Al-Shahwan, I M; Shakeel, M T; Zakri, A M; Katis, N I

    2017-07-01

    During 2014 and 2015, 97 lettuce plants that showed big-vein-disease-like symptoms and seven weed plants were collected from the Riyadh region. DAS-ELISA revealed that 25% and 9% of the lettuce plants were singly infected with LBVaV and MiLBVV, respectively, whereas 63% had a mixed infection with both viruses. The results were confirmed by multiplex reverse transcription polymerase chain reaction using primers specific for LBVaV and MiLBVV. LBVaV and MiLBVV were also detected in Sonchus oleraceus and Eruca sativa, respectively. The nucleotide sequence of LBVaV and MiLBVV Saudi isolates ranged from 94.3-100%, and their similarities to isolates with sequences in the GenBank database ranged from 93.9 to 99.6% and 93.8 to 99.3%, respectively. Olpidium sp. was present in the roots of lettuce plants with big-vein disease and it was shown to facilitate transmission of both viruses.

  14. Identification, genetic localization, and allelic diversity of selectively amplified microsatellite polymorphic loci in lettuce and wild relatives (Lactuca spp.).

    Science.gov (United States)

    Witsenboer, H; Michelmore, R W; Vogel, J

    1997-12-01

    Selectively amplified microsatellite polymorphic locus (SAMPL) analysis is a method of amplifying microsatellite loci using generic PCR primers. SAMPL analysis uses one AFLP primer in combination with a primer complementary to microsatellite sequences. SAMPL primers based on compound microsatellite sequences provided the clearest amplification patterns. We explored the potential of SAMPL analysis in lettuce to detect PCR-based codominant microsatellite markers. Fifty-eight SAMPLs were identified and placed on the genetic map. Seventeen were codominant. SAMPLs were dispersed with RFLP markers on 11 of the 12 main linkage groups in lettuce, indicating that they have a similar genomic distribution. Some but not all fragments amplified by SAMPL analysis were confirmed to contain microsatellite sequences by Southern hybridization. Forty-five cultivars of lettuce and five wild species of Lactuca were analyzed to determine the allelic diversity for codominant SAMPLs. From 3 to 11 putative alleles were found for each SAMPL; 2-6 alleles were found within Lactuca sativa and 1-3 alleles were found among the crisphead genotypes, the most genetically homogeneous plant type of L. sativa. This allelic diversity is greater than that found for RFLP markers. Numerous new alleles were observed in the wild species; however, there were frequent null alleles. Therefore, SAMPL analysis is more applicable to intraspecific than to interspecific comparisons. A phenetic analysis based on SAMPLs resulted in a dendrogram similar to those based on RFLP and AFLP markers.

  15. Improving Water Use Efficiency of Lettuce (Lactuca sativa L.) Using Phosphorous Fertilizers.

    Science.gov (United States)

    Alkhader, Asad M F; Abu Rayyan, Azmi M

    2013-01-01

    A greenhouse pot experiment was conducted to evaluate the effect of phosphorous (P) fertilizers application to an alkaline calcareous soil on the water use efficiency (WUE) of lettuce cultivar "robinson" of iceberg type. Head fresh and dry weights, total water applied and WUE were affected significantly by the P fertilizer type and rate. P fertilizers addition induced a significant enhancement in the WUE and fresh and dry weights of the crop. A local phosphate rock (PR) applied directly was found to be inferior to the other types of P fertilizers (Mono ammonium phosphate (MAP), Single superphosphate (SSP), and Di ammonium phosphate ((DAP)). MAP fertilizer at 375 and 500 kg P2O5/ha application rates recorded the highest significant values of head fresh weight and WUE, respectively.

  16. Crescimento de alface hidropônica sob diferentes intervalos de irrigação Hydroponic lettuce growth under differents irrigation intervals

    Directory of Open Access Journals (Sweden)

    Fábio Zanella

    2008-04-01

    Full Text Available O intervalo entre irrigações é um importante critério a ser observado durante o cultivo hidropônico de hortaliças. Nesse contexto, objetivou-se com este trabalho avaliar a produtividade de duas cultivares de alface (Lactuca sativa L., Regina 2000 e Lucy Brown sob três intervalos de irrigação. O experimento foi conduzido no Centro Universitário Luterano de Ji-Paraná (CEULJI/ULBRA, entre setembro e dezembro de 2006. Foram testados três intevalos entre irrigações: 5; 15 e 30 minutos. Cada tratamento constou de quatro repetições de cada cultivar, em delineamento inteiramente casualisado. Analisou-se o número de folhas.planta-1, a massa fresca e massa seca total de cada planta. O aumento no intervalo entre irrigações levou a uma menor produção da alface. Assim, o intervalo de 5 minutos entre irrigações promoveu o maior ganho de massa para as duas cultivares avaliadas.The interval among irrigations is an important criterion taken into account during the hidroponic cultivation of vegetables. Thus, the present work aimed to evaluate the productivity of two lettuce (Lactuca sativa L. cultivars, Regina 2000 and Lucy Brown, in three irrigations intervals. The experiment was carried out at the Centro Universitário Luterano de Ji-Paraná (CEULJ/ULBRA, from September to December 2006. Three intervals between irrigations were used: 5; 15 and 30 minutes. Each treatment had four replications of both cultivars, in a complete randomized outline. The number of leaves.plant-1, total fresh mass and total dry mass were analyzed. There was an increase of the lettuce production according to the increase of the irrigation interval. Thus, 5 minutes among irrigations promoted the greater gain of mass for both cultivars evaluated.

  17. Growing patterns to produce 'nitrate-free' lettuce (Lactuca sativa).

    Science.gov (United States)

    Croitoru, Mircea Dumitru; Muntean, Daniela-Lucia; Fülöp, Ibolya; Modroiu, Adriana

    2015-01-01

    Vegetables can contain significant amounts of nitrate and, therefore, may pose health hazards to consumers by exceeding the accepted daily intake for nitrate. Different hydroponic growing patterns were examined in this work in order to obtain 'nitrate-free lettuces'. Growing lettuces on low nitrate content nutrient solution resulted in a significant decrease in lettuces' nitrate concentrations (1741 versus 39 mg kg(-1)), however the beneficial effect was cancelled out by an increase in the ambient temperature. Nitrate replacement with ammonium was associated with an important decrease of the lettuces' nitrate concentration (from 1896 to 14 mg kg(-1)) and survival rate. An economically feasible method to reduce nitrate concentrations was the removal of all inorganic nitrogen from the nutrient solution before the exponential growth phase. This method led to lettuces almost devoid of nitrate (10 mg kg(-1)). The dried mass and calcinated mass of lettuces, used as markers of lettuces' quality, were not influenced by this treatment, but a small reduction (18%, p < 0.05) in the fresh mass was recorded. The concentrations of nitrite in the lettuces and their modifications are also discussed in the paper. It is possible to obtain 'nitrate-free' lettuces in an economically feasible way.

  18. Virus diseases in lettuce in the Mediterranean basin.

    Science.gov (United States)

    Moreno, Aranzazu; Fereres, Alberto

    2012-01-01

    Lettuce is frequently attacked by several viruses causing disease epidemics and considerable yield losses along the Mediterranean basin. Aphids are key pests and the major vectors of plant viruses in lettuce fields. Lettuce mosaic virus (LMV) is probably the most important because it is seed-transmitted in addition to be transmissible by many aphid species that alight on the crop. Tomato spotted wilt virus (TSWV) is another virus that causes severe damage since the introduction of its major vector, the thrips Frankliniella occidentalis. In regions with heavy and humid soils, Lettuce Mirafiori big-vein virus (LMBVV) can also produce major yield losses. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Biotic Stress Shifted Structure and Abundance of Enterobacteriaceae in the Lettuce Microbiome

    Science.gov (United States)

    Erlacher, Armin; Cardinale, Massimiliano; Grube, Martin; Berg, Gabriele

    2015-01-01

    Lettuce cultivars are not only amongst the most popular vegetables eaten raw, they are also involved in severe pathogen outbreaks world-wide. While outbreaks caused by Enterobacteriaceae species are well-studied, less is known about their occurrence in natural environments as well as the impact of biotic stress. Here, we studied the ecology of the human health-relevant bacterial family Enterobacteriaceae and assessed the impact of biotic disturbances by a soil-borne phytopathogenic fungus and Gastropoda on their structure and abundance in mesocosm and pot experiments. Using a polyphasic approach including network analyses of 16S rRNA gene amplicon libraries, quantitative PCR and complementary fluorescence in situ hybridization (FISH) microscopy we found substantial yet divergent Enterobacteriaceae communities. A similar spectrum of 14 genera was identified from rhizo- and phyllospheres but the abundance of Enterobacteriaceae was on average 3fold higher in phyllosphere samples. Both stress factors shifted the bacterial community of the leaf habitat, characterized by increases of species abundance and diversity. For the rhizosphere, we observed significant structural shifts of Enterobacteriaceae communities but also a high degree of resilience. These results could be confirmed by FISH microscopy but it was difficult to visualize phyllosphere communities. Additional inoculation experiments with Escherichia coli as model revealed their presence below the wax layer as well as in the endosphere of leaves. The observed presence influenced by stress factors and the endophytic life style of Enterobacteriaceae on lettuce can be an important aspect in relation to human health. PMID:25714833

  20. Biotic stress shifted structure and abundance of Enterobacteriaceae in the lettuce microbiome.

    Science.gov (United States)

    Erlacher, Armin; Cardinale, Massimiliano; Grube, Martin; Berg, Gabriele

    2015-01-01

    Lettuce cultivars are not only amongst the most popular vegetables eaten raw, they are also involved in severe pathogen outbreaks world-wide. While outbreaks caused by Enterobacteriaceae species are well-studied, less is known about their occurrence in natural environments as well as the impact of biotic stress. Here, we studied the ecology of the human health-relevant bacterial family Enterobacteriaceae and assessed the impact of biotic disturbances by a soil-borne phytopathogenic fungus and Gastropoda on their structure and abundance in mesocosm and pot experiments. Using a polyphasic approach including network analyses of 16S rRNA gene amplicon libraries, quantitative PCR and complementary fluorescence in situ hybridization (FISH) microscopy we found substantial yet divergent Enterobacteriaceae communities. A similar spectrum of 14 genera was identified from rhizo- and phyllospheres but the abundance of Enterobacteriaceae was on average 3fold higher in phyllosphere samples. Both stress factors shifted the bacterial community of the leaf habitat, characterized by increases of species abundance and diversity. For the rhizosphere, we observed significant structural shifts of Enterobacteriaceae communities but also a high degree of resilience. These results could be confirmed by FISH microscopy but it was difficult to visualize phyllosphere communities. Additional inoculation experiments with Escherichia coli as model revealed their presence below the wax layer as well as in the endosphere of leaves. The observed presence influenced by stress factors and the endophytic life style of Enterobacteriaceae on lettuce can be an important aspect in relation to human health.

  1. Biotic stress shifted structure and abundance of Enterobacteriaceae in the lettuce microbiome.

    Directory of Open Access Journals (Sweden)

    Armin Erlacher

    Full Text Available Lettuce cultivars are not only amongst the most popular vegetables eaten raw, they are also involved in severe pathogen outbreaks world-wide. While outbreaks caused by Enterobacteriaceae species are well-studied, less is known about their occurrence in natural environments as well as the impact of biotic stress. Here, we studied the ecology of the human health-relevant bacterial family Enterobacteriaceae and assessed the impact of biotic disturbances by a soil-borne phytopathogenic fungus and Gastropoda on their structure and abundance in mesocosm and pot experiments. Using a polyphasic approach including network analyses of 16S rRNA gene amplicon libraries, quantitative PCR and complementary fluorescence in situ hybridization (FISH microscopy we found substantial yet divergent Enterobacteriaceae communities. A similar spectrum of 14 genera was identified from rhizo- and phyllospheres but the abundance of Enterobacteriaceae was on average 3fold higher in phyllosphere samples. Both stress factors shifted the bacterial community of the leaf habitat, characterized by increases of species abundance and diversity. For the rhizosphere, we observed significant structural shifts of Enterobacteriaceae communities but also a high degree of resilience. These results could be confirmed by FISH microscopy but it was difficult to visualize phyllosphere communities. Additional inoculation experiments with Escherichia coli as model revealed their presence below the wax layer as well as in the endosphere of leaves. The observed presence influenced by stress factors and the endophytic life style of Enterobacteriaceae on lettuce can be an important aspect in relation to human health.

  2. Expression of 9-cis-EPOXYCAROTENOID DIOXYGENASE4 Is Essential for Thermoinhibition of Lettuce Seed Germination but Not for Seed Development or Stress Tolerance[C][W

    Science.gov (United States)

    Huo, Heqiang; Dahal, Peetambar; Kunusoth, Keshavulu; McCallum, Claire M.; Bradford, Kent J.

    2013-01-01

    Thermoinhibition, or failure of seeds to germinate at warm temperatures, is common in lettuce (Lactuca sativa) cultivars. Using a recombinant inbred line population developed from a lettuce cultivar (Salinas) and thermotolerant Lactuca serriola accession UC96US23 (UC), we previously mapped a quantitative trait locus associated with thermoinhibition of germination to a genomic region containing a gene encoding a key regulated enzyme in abscisic acid (ABA) biosynthesis, 9-cis-EPOXYCAROTENOID DIOXYGENASE4 (NCED4). NCED4 from either Salinas or UC complements seeds of the Arabidopsis thaliana nced6-1 nced9-1 double mutant by restoring germination thermosensitivity, indicating that both NCED4 genes encode functional proteins. Transgenic expression of Salinas NCED4 in UC seeds resulted in thermoinhibition, whereas silencing of NCED4 in Salinas seeds led to loss of thermoinhibition. Mutations in NCED4 also alleviated thermoinhibition. NCED4 expression was elevated during late seed development but was not required for seed maturation. Heat but not water stress elevated NCED4 expression in leaves, while NCED2 and NCED3 exhibited the opposite responses. Silencing of NCED4 altered the expression of genes involved in ABA, gibberellin, and ethylene biosynthesis and signaling pathways. Together, these data demonstrate that NCED4 expression is required for thermoinhibition of lettuce seeds and that it may play additional roles in plant responses to elevated temperature. PMID:23503626

  3. Varietal response to lead by lettuce

    Energy Technology Data Exchange (ETDEWEB)

    John, M.K.

    1977-06-01

    Nine lettuce varieties were hydroponically grown at six substrate Pb concentrations to 50 ppM in substrate. Top and root tissue Pb concentration, amounts assimilated, and translocation to edible tissue were dependent on the variety as well as substrate lead and exposure duration. Even though Pb in substrate was in a precipitated form, lettuce plants could assimilate and translocate Pb. Differential response of varieties with similar morphology indicated genetical regulated physiological mechanisms of Pb assimilation and translocation. This evidence suggests varietal selection could minimize human and animal dietary intake of Pb via food plants. While early growth of some varieties was stimulated by low concentrations of Pb, and high solution concentrations suppressed growth of several varieties, genetic variation also included non-significant response of growth.

  4. An improved method for transformation of lettuce by Agrobacterium tumefaciens with a gene that confers freezing resistance

    Directory of Open Access Journals (Sweden)

    Pileggi Marcos

    2001-01-01

    Full Text Available An efficient method for constructing transgenic lettuce cultivars by Agrobacterium tumefaciens was described by Torres et al., 1993. In the present work, an improvement of the above procedure is described and applied to transform the cultivar Grand Rapids with a mutated P5CS gene. The major modifications were concerned with turning more practical the transformation and regeneration protocols. Also we tried to improve transformation steps by increasing injured area in explants and prolonging co-cultivation with Agrobacteria (in larger concentration. A more significant selective pressure was used against non-transformed plants and bacteria. In these work we were concerned to obtain T1 and T2 seeds. The P5CS gene codes for a delta¹-pyrroline-5-carboxylate synthetase, a bifunctional enzyme that catalyzes two steps of proline biosynthesis in plants (Zhang et al., 1995; Peng et al., 1996, while the mutated gene is insensitive to feedback inhibition by proline. The potential benefit of this gene is to confer water stress resistance (drought, salt, cold due to increased intracellular levels of proline that works like an osmoprotectant. In this work could obtain and characterize transgenic lettuce lineages which are resistant to freezing temperature.

  5. CO₂ enrichment can produce high red leaf lettuce yield while increasing most flavonoid glycoside and some caffeic acid derivative concentrations.

    Science.gov (United States)

    Becker, Christine; Kläring, Hans-Peter

    2016-05-15

    Carbon dioxide (CO2) enrichment is a common practice in greenhouses to increase crop yields up to 30%. Yet, reports on the effect on foliar phenolic compounds vary. We studied the effect on two red leaf lettuce cultivars, grown for 25 days in growth chambers at CO2 concentrations of 200 or 1,000 ppm, with some plants exchanged between treatments after 11 days. As expected, head mass increased with higher CO2 concentration. Regression analysis, corrected for head mass, showed increased concentrations of most flavonoid glycosides at high CO2 concentrations while only some caffeic acid derivatives were increased, and not uniformly in both cultivars. Sugar concentrations increased with CO2 concentration. Generally, conditions in the 10 days before harvest determined concentrations. We suspect that phenolic compounds were mainly accumulated because plenty of precursors were available. The results indicate that CO2 enrichment can result in high yields of red leaf lettuce rich in phenolic compounds. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. THE INFLUENCE OF POTATO CYST NEMATODE G. ROSTOCHIENSIS INFESTATION ON DIFFERENT POTATO CULTIVARS

    Directory of Open Access Journals (Sweden)

    Gregor Urek

    2008-07-01

    Full Text Available The potato cyst nematode Globodera rostochiensis is one of the most serious pests of potato in Slovenia. Precise nematode identification and knowledge about potato cultivars, which are most suitable for growing in the Slovenian climate conditions and most resistant to G. rostochiensis, are necessary to develop an effective integrated pest control. Here we report the results of the influence of G. rostochiensis pathotype Ro1/4 on the yield of different potato cultivars: the susceptible cultivar Desiree, the resistant cultivars White Lady, Miranda, Aladin, Sante and Adora, and the clone KIS 94-1/5-14. The yield of cv. White Lady was the highest and that of susceptible cv. Desiree the lowest. The influence of several resistant and one susceptible potato cultivars on population dynamics of G. rostochiensis was also determined. The total number of cysts/100 cm3 and the number of eggs and juveniles per cyst increased in the susceptible cv. Desiree and decreased in the resistant cultivars White Lady, Sante and Adora.

  7. Wound-induced pectin methylesterases enhance banana (Musa spp. AAA) susceptibility to Fusarium oxysporum f. sp. cubense.

    Science.gov (United States)

    Ma, Li; Jiang, Shuang; Lin, Guimei; Cai, Jianghua; Ye, Xiaoxi; Chen, Houbin; Li, Minhui; Li, Huaping; Takác, Tomás; Samaj, Jozef; Xu, Chunxiang

    2013-05-01

    Recent studies suggest that plant pectin methylesterases (PMEs) are directly involved in plant defence besides their roles in plant development. However, the molecular mechanisms of PME action on pectins are not well understood. In order to understand how PMEs modify pectins during banana (Musa spp.)-Fusarium interaction, the expression and enzyme activities of PMEs in two banana cultivars, highly resistant or susceptible to Fusarium, were compared with each other. Furthermore, the spatial distribution of PMEs and their effect on pectin methylesterification of 10 individual homogalacturonan (HG) epitopes with different degrees of methylesterification (DMs) were also examined. The results showed that, before pathogen treatment, the resistant cultivar displayed higher PME activity than the susceptible cultivar, corresponding well to the lower level of pectin DM. A significant increase in PME expression and activity and a decrease in pectin DM were observed in the susceptible cultivar but not in the resistant cultivar when plants were wounded, which was necessary for successful infection. With the increase of PME in the wounded susceptible cultivar, the JIM5 antigen (low methyestrified HGs) increased. Forty-eight hours after pathogen infection, the PME activity and expression in the susceptible cultivar were higher than those in the resistant cultivar, while the DM was lower. In conclusion, the resistant and the susceptible cultivars differ significantly in their response to wounding. Increased PMEs and thereafter decreased DMs acompanied by increased low methylesterified HGs in the root vascular cylinder appear to play a key role in determination of banana susceptibility to Fusarium.

  8. USE OF PELLETED LETTUCE SEEDS IN BIOAVAILABILITY STUDIES

    Science.gov (United States)

    Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. Th...

  9. USE OF PELLETED LETTUCE SEEDS IN BIOABAILABILITY STUDIES

    Science.gov (United States)

    Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. Th...

  10. Emprego de tipos de cobertura de canteiro no cultivo da alface Evaluation of mulch types on lettuce production

    Directory of Open Access Journals (Sweden)

    Valter C. de Andrade Júnior

    2005-12-01

    Full Text Available Com o objetivo de avaliar o efeito de diferentes coberturas de canteiro sobre as características agronômicas de cultivares de alface (Lactuca sativa L. tipo lisa, foi realizado um experimento na Universidade Vale do Rio Verde em Três Corações (MG. O delineamento experimental utilizado foi de blocos ao acaso em esquema fatorial 5 x 2, proveniente da combinação de cinco tipos de cobertura (plástico preto, capim braquiária seco, casca de arroz, casca de café e solo nu e duas cultivares de alface tipo lisa (Regina e Elisa, com 3 repetições. A colheita foi realizada 42 dias após o transplantio, sendo avaliados a produção total (t ha-1, produção comercial, massa média por planta, diâmetro médio de cabeça, diâmetro médio de caule, número médio de folhas e massa média de raiz. Foi observada interação significativa entre tipos de cobertura x cultivares somente para a característica massa média de raiz, tendo a cultivar Elisa apresentado maior massa média de raiz quando utilizadas as coberturas com casca de café e casca de arroz. A cobertura com casca de café foi a que proporcionou os melhores resultados, superando os demais tipos de cobertura para todas as características avaliadas. A cultivar Regina foi superior à Elisa em quase todas as características estudadas, exceto para diâmetro médio de caule onde não foi observada diferença significativa entre as cultivares. 'Elisa' também apresentou maior massa média de raiz que a cultivar Regina.An experiment was carried out at Universidade Vale do Rio Verde, Minas Gerais State, Brazil, to evaluate the effect of bed coverages on the agronomic characteristics of lettuce cultivars. The experimental design was of randomized complete blocks in a 5 x 2 factorial scheme with five types of mulch (black plastic; dry braquiaria grass; rice husk; coffee husk and nude soil, two leaf lettuce cultivars (Regina and Elisa and three replications. Plants were harvested 42 days after

  11. 7 CFR 319.56-24 - Lettuce and peppers from Israel.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Lettuce and peppers from Israel. 319.56-24 Section 319... Lettuce and peppers from Israel. (a) Lettuce may be imported into the United States from Israel without... protected with sticky traps and prophylactic sprays approved for the crop by Israel; (v) The lettuce must be...

  12. Nutritional value, bioactive compounds, and health benefits of lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Lettuce is one of the most popularly consumed vegetables worldwide but its nutritional value has been underestimated. Lettuce is low in calories and fat but high in fiber. Moreover, lettuce is high in potassium but low in sodium. Lettuce is also a good source of health-beneficial bioactive compounds...

  13. Rearing history affects behaviour and performance of two virulent Nasonovia ribisnigri populations on two lettuce cultivars

    NARCIS (Netherlands)

    Broeke, ten C.J.M.; Dicke, M.; Loon, van J.J.A.

    2014-01-01

    Many aphid species have become virulent to host-plant resistance, which limits the sustainability of insect resistance breeding. However, when this adaptation to resistant plants is associated with fitness costs for the aphids, virulence can be lost in the absence of resistant plants. For two

  14. THE INFLUENCE OF POTATO CYST NEMATODE G. ROSTOCHIENSIS INFESTATION ON DIFFERENT POTATO CULTIVARS

    OpenAIRE

    Gregor Urek; S Širca; Stare Geric; B Dolničar; P Strajnar

    2008-01-01

    The potato cyst nematode Globodera rostochiensis is one of the most serious pests of potato in Slovenia. Precise nematode identification and knowledge about potato cultivars, which are most suitable for growing in the Slovenian climate conditions and most resistant to G. rostochiensis, are necessary to develop an effective integrated pest control. Here we report the results of the influence of G. rostochiensis pathotype Ro1/4 on the yield of different potato cultivars: the susceptible cultiva...

  15. Genomic and environmental selection patterns in two distinct lettuce crop-wild hybrid crosses.

    Science.gov (United States)

    Hartman, Yorike; Uwimana, Brigitte; Hooftman, Danny A P; Schranz, Michael E; van de Wiel, Clemens C M; Smulders, Marinus J M; Visser, Richard G F; van Tienderen, Peter H

    2013-06-01

    Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop-wild crosses of lettuce. We performed quantitative trait loci (QTL) analyses and estimated the fitness distribution of early- and late-generation hybrids. We detected consistent results across field sites and crosses for a fitness QTL at linkage group 7, where a selective advantage was conferred by the wild allele. Two fitness QTL were detected on linkage group 5 and 6, which were unique to one of the crop-wild crosses. Average hybrid fitness was lower than the fitness of the wild parent, but several hybrid lineages outperformed the wild parent, especially in a novel habitat for the wild type. In early-generation hybrids, this may partly be due to heterosis effects, whereas in late-generation hybrids transgressive segregation played a major role. The study of genomic selection patterns can identify crop genomic regions under negative selection across multiple environments and cultivar-wild crosses that might be applicable in transgene mitigation strategies. At the same time, results were cultivar-specific, so that a case-by-case environmental risk assessment is still necessary, decreasing its general applicability.

  16. Resistance of canola cultivars affect life table parameters of Nysius cymoides (Spinola (Hemiptera: Lygaeidae

    Directory of Open Access Journals (Sweden)

    Mollashahi Mehdi

    2016-01-01

    Full Text Available A life table can be used as an important and appropriate tool to evaluate the susceptibility or resistance level of different host plant cultivars to insect pests. In the current study, we determined the suitability or inferiority of five different canola cultivars (Hayula420, Hayula401, Hayula50, Hayula60, RGS to Nysius cymoides, under laboratory conditions. Data were analysed based on the age-stage, two-sex life table theory. Nysius cymoides which fed on Hayula420 had the longest nymphal period, while those which fed on Hayula50 had the shortest nymphal period. Developmental times (sum of incubation and nymphal periods was longest for those which fe d on Hayula420 and the shortest for those which fed on Hayula50. The adult pre-oviposition period (APOP, total pre-oviposition period (TPOP, mean fecundity, and adult longevity of adults reared on different canola cultivars showed significant differences. The highest and lowest net reproductive rates (R0 were obtained for those which fed on Hayula420 (11.40 offspring per individual and Hayula401 (5.47 offspring per individual, respectively. The highest value (0.0395 d-1 for the intrinsic rate of increase (r was obtained for those which fed on Hayula 60 cultivar and the lowest value (0.0261 d-1 for those which fed on Hayula401 cultivar. The shortest and longest mean generation times (T were obtained for those which fed on RGS and H401 cultivars, respectively. The lowest and highest values of life expectancy (exj were obtained for those which fed on RGS and Hayula420 cultivars, respectively. The results showed that Hayula401 and RGS were not susceptible cultivars to N. cymoides. These cultivars showed higher resistance to N. cymoides, while Hayula60, Hayula420, and Hayula50 were found to be suitable cultivars but with lower resistance to N. cymoides, respectively.

  17. Effects of Salt Stress on Germination and Early Seedling Growth of Some Kenyan Rice Cultivars

    International Nuclear Information System (INIS)

    Ochieng, C.A.; Onkware, A.O.

    1999-01-01

    Four rice cultivars (Basmati-217, BW-196, Sindano and Ita-310) were subjected to increasing substrate salinity (0-1.5 Sm -1 ECe), under both laboratory and soil experiments. The salt stress significantly (P -1 ECe) completely inhibited germination in potted soil, but not petri dish tests in the laboratory.It was concluded that the three rice cultivars are susceptible to even mild substrate salinity, and cannot be relied upon for cultivation in saline soils. There is a need to assess the response many of the rice cvv for resistance to salt stress, and, if possible isolate and develop high yielding, resistant cultivars

  18. Agronomic aspects of strip intercropping lettuce with alyssum for biological control of aphids

    OpenAIRE

    Brennan, Eric B.

    2013-01-01

    Organic lettuce growers in California typically use insectary strips of alyssum (Lobularia maritima (L.) Desv.) to attract hoverflies (Syrphidae) that provide biological control of aphids. A two year study with transplanted organic romaine lettuce in Salinas, California investigated agronomic aspects of lettuce monoculture and lettuce-alyssum strip intercropping on beds in replacement intercropping treatments where alyssum transplants replaced 2 to 8% of the lettuce transplants, and in additi...

  19. Fusarium head blight incidence and mycotoxin accumulation in three durum wheat cultivars in relation to sowing date and density

    Science.gov (United States)

    Gorczyca, Anna; Oleksy, Andrzej; Gala-Czekaj, Dorota; Urbaniak, Monika; Laskowska, Magdalena; Waśkiewicz, Agnieszka; Stępień, Łukasz

    2018-02-01

    Durum wheat ( Triticum turgidum var. durum) is an important crop in Europe, particularly in the Mediterranean countries. Fusarium head blight (FHB) is considered as one of the most damaging diseases, resulting in yield and quality reduction as well as contamination of grain with mycotoxins. Three winter durum wheat cultivars originating from Austria, Slovakia, and Poland were analyzed during 2012-2014 seasons for FHB incidence and Fusarium mycotoxin accumulation in harvested grain. Moreover, the effects of sowing density and delayed sowing date were evaluated in the climatic conditions of Southern Poland. Low disease severity was observed in 2011/2012 in all durum wheat cultivars analyzed, and high FHB occurrence was recorded in 2012/2013 and 2013/2014 seasons. Fusarium graminearum was the most abundant pathogen, followed by Fusarium avenaceum. Through all three seasons, cultivar Komnata was the most susceptible to FHB and to mycotoxin accumulation, while cultivars Auradur and IS Pentadur showed less symptoms. High susceptibility of cv. Komnata was reflected by the number of Fusarium isolates and elevated mycotoxin (deoxynivalenol, zearalenone, and moniliformin) content in the grain of this cultivar across all three seasons. Nivalenol was identified in the samples of cv. Komnata only. Genotype-dependent differences in FHB susceptibility were observed for the plants sown at optimal date but not at delayed sowing date. It can be hypothesized that cultivars bred in Austria and Slovakia show less susceptibility towards FHB than the cultivar from Poland because of the environmental conditions allowing for more efficient selection of breeding materials.

  20. Microbiological quality and safety assessment of lettuce production in Brazil.

    Science.gov (United States)

    Ceuppens, Siele; Hessel, Claudia Titze; de Quadros Rodrigues, Rochele; Bartz, Sabrina; Tondo, Eduardo César; Uyttendaele, Mieke

    2014-07-02

    The microbiological quality and safety of lettuce during primary production in Brazil were determined by enumeration of hygiene indicators Escherichia coli, coliforms and enterococci and detection of enteric pathogens Salmonella and E. coli O157:H7 in organic fertilizers, soil, irrigation water, lettuce crops, harvest boxes and worker's hands taken from six different lettuce farms throughout the crop growth cycle. Generic E. coli was a suitable indicator for the presence of Salmonella and E. coli O157:H7, while coliforms and enterococci were not. Few pathogens were detected: 5 salmonellae and 2 E. coli O157:H7 from 260 samples, of which only one was lettuce and the others were manure, soil and water. Most (5/7) pathogens were isolated from the same farm and all were from organic production. Statistical analysis revealed the following environmental and agro-technical risk factors for increased microbial load and pathogen prevalence in lettuce production: high temperature, flooding of lettuce fields, application of contaminated organic fertilizer, irrigation with water of inferior quality and large distances between the field and toilets. Control of the composting process of organic fertilizers and the irrigation water quality appear most crucial to improve and/or maintain the microbiological quality and safety during the primary production of lettuce. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. BRS Progresso – Rye cultivar

    Directory of Open Access Journals (Sweden)

    Alfredo do Nascimento Junior

    2014-10-01

    Full Text Available The rye cultivar BRS Progresso, developed by the Brazilian Agricultural Research Corporation (Embrapa, is the result of a synthetic cross of 18 open-pollinated, self-incompatible lines, resistant to stem rust.

  2. Susceptibility of South African dry bean cultivars to bacterial diseases

    African Journals Online (AJOL)

    African Crop Science Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 19, No 4 (2011) >. Log in or Register to get access to full text downloads.

  3. Undergraduate Sustainable Learning: Effects of Sustainable Soilless Media on Production and Sensory Evaluation of Cucumbers, Basil, Parsley, and Lettuce

    Directory of Open Access Journals (Sweden)

    Victoria Russell

    2011-08-01

    Full Text Available Modern greenhouse production has been ~100% reliant on fossil fuels for all inputs (glazing, heating, fertilization, lighting, post-harvest. Recent innovations may reduce fossil fuel dependence but their effectiveness may not be thoroughly tested. To promote education in sustainable production, undergraduate students in Greenhouse Management class (Hort 3002W; University of Minnesota tested the effectiveness of two organic or ‘sustainable’ soilless media (Sunshine Natural and Organic Growing Mix, Sungro Metro-Mix Special Blend with a control (Sunshine LC8 Professional for crop production (height, leaf/flower number, yield and sensory evaluations (appearance, texture, taste, purchase of cucumbers (‘Big Burpless Hybrid’, ‘Sweet Burpless Hybrid’, basil (‘Opal Purple’, ‘Redleaf’, parsley (‘Green River’, ‘Extra Curled Dwarf’, ‘Hamburg’, and lettuce (Flying Saucer ‘Green’, ‘Red’. Significant differences between sustainable vs. control soils occurred for plant growth, depending on vegetative or reproductive traits, crops, and cultivars. These differences occasionally disappeared for sensory evaluation of edible components. In most crops, however, cultivars were highly significant factors. Undergraduate research can be used to provide directionality for future vegetable and herb plant breeding to focus on creating cultivars with increased yield and high consumer acceptance when grown in sustainable greenhouse soilless mixes.

  4. Genetic resources collections of leafy vegetables (lettuce, spinach, chicory, artichoke, asparagus, lamb’s lettuce, rhubarb and rocket salad): composition and gaps

    NARCIS (Netherlands)

    Treuren, van R.; Coquin, P.; Lohwasser, U.

    2012-01-01

    Lettuce, spinach and chicory are generally considered the main leafy vegetables, while a fourth group denoted by ‘minor leafy vegetables’ includes, amongst others, rocket salad, lamb’s lettuce, asparagus, artichoke and rhubarb. Except in the case of lettuce, central crop databases of leafy

  5. Effect of population density of lettuce intercropped with rocket on productivity and land-use efficiency

    Science.gov (United States)

    2018-01-01

    The objective of this study was to evaluate the influence of the spacing of lettuce rows on the production of a lettuce-rocket intercropping system over two growing seasons (11 August to 25 September 2011 and 12 January to 24 February 2012) in Jaboticabal, São Paulo, Brazil. We evaluated 11 treatments in each season: lettuce-rocket intercrops with five row spacings for the lettuce (0.20, 0.25, 0.30, 0.35 and 0.40 m) and the rocket planted midway between the lettuce rows, sole crops of lettuce at the same five row spacings and a sole crop of rocket. Fresh and dry masses of the lettuce and rocket and number of lettuce leaves per plant were highest with a lettuce row spacing of 0.40 m, but the productivities of the lettuce and rocket were higher with a lettuce row spacing of 0.20 m. The productivities and fresh and dry weights of the lettuce and rocket and the number of lettuce leaves per plant were highest in the sole crops, but the fresh and dry weights of the rocket were higher with intercropping. The land equivalent ratios were >1.0 in both seasons in all intercrops and were highest for the densest crop (1.41). Intercropping was therefore 41% more efficient than sole cropping for the production of lettuce and rocket. PMID:29698401

  6. Irrigation and nitrogen level affect lettuce yield in greenhouse ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... and it achieves very high irrigation efficiency and uses. *Corresponding ... serious harmful effect on lettuce growing (Table 1). During the ... Seeds were sown in a seed bed under greenhouse conditions on. October 20th in ...

  7. Persistence of 14C maneb in lettuce plants an soil

    International Nuclear Information System (INIS)

    Bennaceur, M.; Sennaoui, Z.; Meguenni, H.

    1992-10-01

    Maneb residue is studied on lettuce plant and soil after spraying on greenhouse with 14C maneb. The residues declined with time. After 37 days from the application, 14C maneb residues in water extracts declined to 1,5. 10-2ug/g from 5,8. 10-1ug/g of the zero day sample in lettuce plants and 4,6. 10-3ug/g from 1,73. 10-1ug/g in soil. The 14C internals residues in lettuce and soil increase respectively till 16 days and 24 days, then decrease to 88% and 4,05% after 37 days. ETU was present in lettuce plant after 8 days then decreases with time. Two metabolites were identified by TLC (EU,ETU)

  8. The Inlfuence of Biochar on Growth of Lettuce and Potato

    Institute of Scientific and Technical Information of China (English)

    Kalika P. Upadhyay; Doug George; Roger S. Swift; Victor Galea

    2014-01-01

    Pot experiments were conducted in a glasshouse to determine the growth pattern of lettuce, true potato seedlings (TPS) and single node cuttings of TPS in response to biochar. The treatments were arranged in a randomized complete block design with 5 treatments (0, 10, 30, 50 and 100 t ha-1) of biochar from greenwaste with 5 replications in lettuce, 10 in TPS and 5 in single node cuttings of TPS. The observations recorded on growth parameters showed that biochar had signiifcant effect on growth of lettuce but no consistent effect on growth of TPS and single node cuttings. Among the biochar rates, 30 t ha-1 had the greatest inlfuence on overall growth of lettuce. The pH and electrical conductivity increased as the biochar rates increased in all experiments. These results provide an avenue for soil management system by using biochar as an amendment in horticultural crops. However, their veriifcation in the ifeld is important for speciifc recommendations.

  9. Lettuce achene invigoration through osmopriming at supraoptimal temperature

    International Nuclear Information System (INIS)

    Jahangir, M.M.; Amjad, M.; Iqbal, Q.; Nawaz, A.; Afzal, I.

    2009-01-01

    The effect of osmopriming on lettuce achene invigoration at supra optimal temperature (35degreeC) was investigated in the present study. Osmopriming of lettuce achene with KNO/sub 3/ (0.25%, 0.5% and 1%), CaCl/sub 2/ (15 mM, 25 mM, 50 mM) and PEG 8000 (0.1 g/ml H/sub 2/O, 0.2 g/ml H/sub 2/O, 0.3g/ml H/sub 2/O) alleviated thermodormancy and improved lettuce achene's vigor. Moreover, priming significantly improved final germination % age, energy of germination, germination index, shoot length, root length, vigor index and reduced mean germination time and time taken to 50% germination, as compared to control, when seeds were subjected to supra-optimal germination environments. It can be concluded that osmopriming can act as effective tool to invigorate lettuce seeds at supra optimal temperature. (author)

  10. High-Throughput Screening of Sensory and Nutritional Characteristics for Cultivar Selection in Commercial Hydroponic Greenhouse Crop Production

    Directory of Open Access Journals (Sweden)

    Atef M. K. Nassar

    2015-01-01

    Full Text Available Hydroponic greenhouse-grown and store-bought cultivars of tomato (cherry and beefsteak, cucumbers, bibb lettuce, and arugula were investigated to see if they could be distinguished based on sensory qualities and phytonutrient composition. Only the more dominant sensory criteria were sufficiently robust to distinguish between cultivars and could form the core of a consolidated number of criteria in a more discriminating sensory evaluation test. Strong determinants for cultivar selection within each crop included the following: mineral analysis (particularly Cu, Fe, K, Mg, and P; total carotenoids (particularly β-carotene, lycopene, and lutein; total carbohydrate (except in arugula; organic acids; total phenolics and total anthocyanins (except in cucumber. Hydroponically grown and store-bought produce were of similar quality although individual cultivars varied in quality. Storage at 4°C for up to 6 days did not affect phytonutrient status. From this, we conclude that “freshness,” while important, has a longer duration than the 6 days used in our study. Overall, the effect of cultivar was more important than the effect of growing method or short-term storage at 4°C under ideal storage conditions.

  11. Divergência genética entre genótipos de alface por meio de marcadores AFLP Genetics divergence among lettuce genotypes by AFLP markers

    Directory of Open Access Journals (Sweden)

    Cristina Soares de Sousa

    2007-01-01

    Full Text Available Considerando a restrita diversidade de espécies disponíveis para nutrir a carência de vitaminas no Brasil, Kerr e colaboradores, desde 1981, vêm desenvolvendo pesquisas para melhoramento genético de hortaliças ricas em vitamina A. Dentre elas, obtiveram uma cultivar de alface, denominada Uberlândia 10.000 com 10.200 UI de vitamina A em 100 gramas de folha fresca. Este trabalho objetivou comparar o grau de divergência genética entre a cultivar Uberlândia 10.000 e seus parentais para avaliar a eficiência da seleção utilizada, por meio da técnica AFLP. Foram utilizados os seguintes genótipos de alface: Maioba, Salad Bowl-Mimosa, Moreninha-de-Uberlândia, Vitória de Santo Antão, Uberlândia 10.000 lisa 8.ª e 9.ª geração e Uberlândia 10.000 crespa 8.ª e 9.ª geração. A técnica AFLP foi eficiente para identificar genótipos muito próximos e para estudos de progênies em alface. O primer PR15 permitiu a separação da forma lisa e crespa com 1,8% de divergência genética e a oitava da nona geração com apenas 0,71%. Com o estudo da filogenia da cultivar pode-se observar que o programa de melhoramento foi desenvolvido com sucesso, pois a cultivar obtida Uberlândia 10.000 possui alto teor de vitamina A e 92% de similaridade com o parental Vitória de Santo Antão. O primer PR11 conseguiu identificar polimorfismo entre cultivares de alta e baixa resistência à septoriose, sugerindo a possibilidade destas bandas estarem relacionadas à resistência.Considering the restricted diversity of species available to counteract vitamin deficiencies in Brazil, Kerr and coworkers have been engaged since 1981, in developing genetic improved garden vegetables rich in vitamin A. One of these vegetables is the lettuce cultivar Uberlândia 10,000, which contains 10,200 UI of vitamin A per 100 grams of fresh leaves. This study compares the genetic diversity between Uberlândia 10,000 and its parental, evaluating selection efficiency through

  12. Cisgenic Rvi6 scab-resistant apple lines show no differences in Rvi6 transcription when compared with conventionally bred cultivars

    NARCIS (Netherlands)

    Chizzali, Cornelia; Gusberti, Michele; Schouten, H.J.; Gessler, Cesare; Broggini, G.A.L.

    2016-01-01

    Main conclusion: The expression of the apple scab resistance geneRvi6in different apple cultivars and lines is not modulated by biotic or abiotic factors.All commercially important apple cultivars are susceptible to Venturia inaequalis, the causal organism of apple scab. A limited number of apple

  13. Retrospectiva e tendência da alfacicultura brasileira Retrospective and trends of Brazilian lettuce crop

    Directory of Open Access Journals (Sweden)

    Fernando Cesar Sala

    2012-06-01

    Full Text Available A alface é considerada a principal hortaliça folhosa no Brasil. Nas ultimas décadas, houve muitas mudanças quanto aos tipos varietais predominantes no país bem como para a preferência do uso de semente peletizada. O domínio do cultivo da alface lisa foi até a década de 90 com as cultivares do tipo 'manteiga' e 'Regina'. Posteriormente, houve uma mudança para o tipo crespa e que, atualmente, corresponde ao principal segmento cultivado no Brasil. A ausência de formação de cabeça aliada à presença de folhas flabeladas conferiram a esse tipo de alface uma melhor adaptação no cultivo de verão com altas temperaturas e índices de pluviosidade. A preferência brasileira pela alface crespa é um fato único na alfacicultura mundial. A alface americana vem apresentando maiores índices de crescimento e aceitação pelo mercado consumidor. Apesar de apresentar formação de cabeça e que tem limitado seu cultivo no verão, na ausência de cultivo protegido, suas folhas mais espessas têm conferido melhor sabor, crocância e durabilidade pós-colheita na alface americana. Alface com folha espessa é mandatória para o mercado de processamento que apresenta alta tendência de crescimento. Considerações sobre o melhoramento genético para contribuir, pelo menos em parte, com essa situação são discutidas com o surgimento de novos tipos varietais tropicalizados, com a tendência de segmentação de mercado e da necessidade de uma cadeia pós-colheita mais eficiente.Lettuce is considered the main leafy vegetable crop in Brazil. In recent decades, many changes occurred towards the varietal types as well as in the preference for pelleted seeds. Until mid 90 decade, the dominant varieties of looseleaf lettuce were the type 'White Boston' and 'Regina'. Later, there was a change toward the Grand Rapids type which represents the main varietal segment grown in Brazil. The non-head Grand Rapids type with its earliness performed better adaptation

  14. Desempenho agroeconômico do bicultivo de alface em sistema solteiro e consorciado com cenoura Agrieconomic performance of lettuce under bicropping, sole crop and intercropped with carrot

    Directory of Open Access Journals (Sweden)

    Eliane Q. de Oliveira

    2004-12-01

    ções', tiveram os melhores indicadores agroeconômicos, com índices de uso eficiente da terra de 2,16 e 2,15, taxas de retorno de 2,05 e 2,33, e índices de lucratividade de 53,92% e 59,83%, respectivamente.Two experiments were carried out from September to May 2002, in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the agrieconomic performance of two lettuce groups under bicropping, sole crop and intercropping system with two carrot cultivars (Alvorada and Brasília in a strip-intercropping arrangement. The experimental design was of group balanced blocks with four replications. The evaluated lettuce cvs. were from the crispleaf group (Lucy Brown, Tainá, Laurel and Verônica and looseleaf group (Babá de Verão, Maravilha das Quatro Estações, Elisa and Carolina. In the intercropping experiment, the split-plot scheme was used. In the plots the carrot cvs. were assigned and in the subplots the lettuce cvs. of both groups. From the lettuce cvs. were obtained data of leaf yield and, for the carrot cvs. were obtained total and commercial yield, besides the root classes. Agrieconomic indices such as land equivalent ratio, gross and net income, monetary advantage, rate of return and profit margin were used to measure the efficiency of intercropping systems. No significant interaction was obtained between carrot and lettuce cvs. in yield of both crops. Carrot cvs. did not influence crop yield and lettuce cvs. had no influence on carrot yield. In the bicropping of lettuce with carrot, the cvs. Lucy Brown and Tainá (crispleaf group and Babá de Verão and Maravilha das Quatro Estações (looseleaf group had presented the best yield performance in the first planting. In the second planting, only cv. Maravilha das Quatro Estações of looseleaf lettuce group had presented the best performance under intercropping. Lettuce cvs. of crispleaf group intercropped with carrot had presented the best yield performance when compared to those of the looseleaf group. The intercropping

  15. Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

    Science.gov (United States)

    Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

    2015-05-01

    Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Boron application improves yield of rice cultivars under high temperature stress during vegetative and reproductive stages.

    Science.gov (United States)

    Shahid, Mohammad; Nayak, Amaresh Kumar; Tripathi, Rahul; Katara, Jawahar Lal; Bihari, Priyanka; Lal, Banwari; Gautam, Priyanka

    2018-04-12

    It is reported that high temperatures (HT) would cause a marked decrease in world rice production. In tropical regions, high temperatures are a constraint to rice production and the most damaging effect is on spikelet sterility. Boron (B) plays a very important role in the cell wall formation, sugar translocation, and reproduction of the rice crop and could play an important role in alleviating high temperature stress. A pot culture experiment was conducted to study the effect of B application on high temperature tolerance of rice cultivars in B-deficient soil. The treatments comprised of four boron application treatments viz. control (B0), soil application of 1 kg B ha -1 (B1), soil application of 2 kg B ha -1 (B2), and foliar spray of 0.2% B (Bfs); three rice cultivars viz. Annapurna (HT stress tolerant), Naveen, and Shatabdi (both HT stress susceptible); and three temperature regimes viz. ambient (AT), HT at vegetative stage (HTV), and HT at reproductive stage (HTR). The results revealed that high temperature stress during vegetative or flowering stage reduced grain yield of rice cultivars mainly because of low pollen viability and spikelet fertility. The effects of high temperature on the spikelet fertility and grain filling varied among cultivars and the growth stages of plant when exposed to the high temperature stress. Under high temperature stress, the tolerant cultivar displays higher cell membrane stability, less accumulation of osmolytes, more antioxidant enzyme activities, and higher pollen viability and spikelet fertility than the susceptible cultivars. In the present work, soil application of boron was effective in reducing the negative effects of high temperature both at vegetative and reproductive stages. Application of B results into higher grain yield under both ambient and high temperature condition over control for all the three cultivars; however, more increase was observed for the susceptible cultivar over the tolerant one. The results

  17. Boron application improves yield of rice cultivars under high temperature stress during vegetative and reproductive stages

    Science.gov (United States)

    Shahid, Mohammad; Nayak, Amaresh Kumar; Tripathi, Rahul; Katara, Jawahar Lal; Bihari, Priyanka; Lal, Banwari; Gautam, Priyanka

    2018-04-01

    It is reported that high temperatures (HT) would cause a marked decrease in world rice production. In tropical regions, high temperatures are a constraint to rice production and the most damaging effect is on spikelet sterility. Boron (B) plays a very important role in the cell wall formation, sugar translocation, and reproduction of the rice crop and could play an important role in alleviating high temperature stress. A pot culture experiment was conducted to study the effect of B application on high temperature tolerance of rice cultivars in B-deficient soil. The treatments comprised of four boron application treatments viz. control (B0), soil application of 1 kg B ha-1 (B1), soil application of 2 kg B ha-1 (B2), and foliar spray of 0.2% B (Bfs); three rice cultivars viz. Annapurna (HT stress tolerant), Naveen, and Shatabdi (both HT stress susceptible); and three temperature regimes viz. ambient (AT), HT at vegetative stage (HTV), and HT at reproductive stage (HTR). The results revealed that high temperature stress during vegetative or flowering stage reduced grain yield of rice cultivars mainly because of low pollen viability and spikelet fertility. The effects of high temperature on the spikelet fertility and grain filling varied among cultivars and the growth stages of plant when exposed to the high temperature stress. Under high temperature stress, the tolerant cultivar displays higher cell membrane stability, less accumulation of osmolytes, more antioxidant enzyme activities, and higher pollen viability and spikelet fertility than the susceptible cultivars. In the present work, soil application of boron was effective in reducing the negative effects of high temperature both at vegetative and reproductive stages. Application of B results into higher grain yield under both ambient and high temperature condition over control for all the three cultivars; however, more increase was observed for the susceptible cultivar over the tolerant one. The results suggest

  18. Susceptibility of ornamental pepper banker plant candidates to common greenhouse pests

    Science.gov (United States)

    Susceptibility of four potential ornamental pepper banker plant candidates [Black Pearl (BP), Explosive Ember (EE), Masquerade (MA), Red Missile (RM), and a commercial pepper cultivar Blitz (BL)] were evaluated against three common greenhouse pests - Bemisia tabaci, Polyphagotarsonemus latus and Fra...

  19. Low cost industrial production of coagulation factor IX bioencapsulated in lettuce cells for oral tolerance induction in hemophilia B.

    Science.gov (United States)

    Su, Jin; Zhu, Liqing; Sherman, Alexandra; Wang, Xiaomei; Lin, Shina; Kamesh, Aditya; Norikane, Joey H; Streatfield, Stephen J; Herzog, Roland W; Daniell, Henry

    2015-11-01

    Antibodies (inhibitors) developed by hemophilia B patients against coagulation factor IX (FIX) are challenging to eliminate because of anaphylaxis or nephrotic syndrome after continued infusion. To address this urgent unmet medical need, FIX fused with a transmucosal carrier (CTB) was produced in a commercial lettuce (Simpson Elite) cultivar using species specific chloroplast vectors regulated by endogenous psbA sequences. CTB-FIX (∼1 mg/g) in lyophilized cells was stable with proper folding, disulfide bonds and pentamer assembly when stored ∼2 years at ambient temperature. Feeding lettuce cells to hemophilia B mice delivered CTB-FIX efficiently to the gut immune system, induced LAP(+) regulatory T cells and suppressed inhibitor/IgE formation and anaphylaxis against FIX. Lyophilized cells enabled 10-fold dose escalation studies and successful induction of oral tolerance was observed in all tested doses. Induction of tolerance in such a broad dose range should enable oral delivery to patients of different age groups and diverse genetic background. Using Fraunhofer cGMP hydroponic system, ∼870 kg fresh or 43.5 kg dry weight can be harvested per 1000 ft(2) per annum yielding 24,000-36,000 doses for 20-kg pediatric patients, enabling first commercial development of an oral drug, addressing prohibitively expensive purification, cold storage/transportation and short shelf life of current protein drugs. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Low cost industrial production of coagulation factor IX bioencapsulated in lettuce cells for oral tolerance induction in hemophilia B

    Science.gov (United States)

    Su, Jin; Zhu, Liqing; Sherman, Alexandra; Wang, Xiaomei; Lin, Shina; Kamesh, Aditya; Norikane, Joey H.; Streatfield, Stephen J.; Herzog, Roland W.; Daniell, Henry

    2015-01-01

    Antibodies (inhibitors) developed by hemophilia B patients against coagulation factor IX (FIX) are challenging to eliminate because of anaphylaxis or nephrotic syndrome after continued infusion. To address this urgent unmet medical need, FIX fused with a transmucosal carrier (CTB) was produced in a commercial lettuce (Simpson Elite) cultivar using species specific chloroplast vectors regulated by endogenous psbA sequences. CTB-FIX (~1mg/g) in lyophilized cells was stable with proper folding, disulfide bonds and pentamer assembly when stored ~2 years at ambient temperature. Feeding lettuce cells to hemophilia B mice delivered CTB-FIX efficiently to the gut immune system, induced LAP+ regulatory T cells and suppressed inhibitor/IgE formation and anaphylaxis against FIX. Lyophilized cells enabled 10-fold dose escalation studies and successful induction of oral tolerance was observed in all tested doses. Induction of tolerance in such a broad dose range should enable oral delivery to patients of different age groups and diverse genetic background. Using Fraunhofer cGMP hydroponic system, ~870 kg fresh or 43.5 kg dry weight can be harvested per 1000 ft2 per annum yielding 24,000–36,000 doses for 20-kg pediatric patients, enabling first commercial development of an oral drug, addressing prohibitively expensive purification, cold storage/transportation and short shelf life of current protein drugs. PMID:26302233

  1. Susceptibility Testing

    Science.gov (United States)

    ... Marker Bicarbonate (Total CO2) Bilirubin Blood Culture Blood Gases Blood Ketones Blood Smear Blood Typing Blood Urea ... hours depending on the method used. There are commercial tests available that offer rapid susceptibility testing and ...

  2. Influence of Soil Temperature on Meloidogyne incognita Resistant and Susceptible Cotton, Gossypium hirsutum

    OpenAIRE

    Carter, William W.

    1982-01-01

    The degree of resistance by a cotton plant to Meloidogyne incognita is affected by soil temperature, particularly in moderately resistant cultivars, The total number of nematodes in the resistant and moderately resistant rools at 35 C was equal to, or greater than, the number in susceptible roots at 20, 25, or 30 C. A shift in numbers to developing and egg-bearing forms of nematodes in the susceptible cultivar as tentperature increased indicates development was affected by temperature rather ...

  3. Elemental Composition of Two Rice Cultivars under Potentially Toxic an Aquept and Aquent

    Directory of Open Access Journals (Sweden)

    Adesola Olutayo OLALEYE

    2009-12-01

    Full Text Available Iron toxicity is a major nutrient disorder affecting rice production of wetland rice in the irrigated and rainfed ecosystem in West Africa sub-region. Little attention has been paid to evaluating nutrient contents of rice cultivars grown on such soils and their relationship to the iron toxicity scores, grain yield and dry matter yields. A pot experiment was conducted on two potentially Fe-toxic soils (Aeric Fluvaquent and Aeric Tropaquept. The experiment was a 2 x 2 x 4 factorial experiment with three replicates in arranged in a randomized fashion. The factors were two soil types, two rice cultivars (ITA 212 and tolerant (Suakoko 8 and four Fe 2+ levels (control, 1000, 3000 and 4000 mg L-1. The result showed that for both susceptible cultivar (ITA 212 and the relatively tolerant (Suakoko 8 cultivar, little or no differences were observed in their elemental composition with regards to micro and macro-nutrients. For the susceptible cultivar, results showed that none of the tissue nutrients significantly relates to iron toxicity scores (ITS, grain yield and dry matter yield on both soil types. However, for the tolerant cultivar, ITS was observed to be significantly related to tissue K and P contents on the two soil types respectively. Tissue Ca and Mg were observed to be significantly related to the dry matter yield (DMY on Aeric Tropquept. It could be concluded that for these rice cultivars grown on two potentially Fe-toxic soils, different tissue nutrients may trigger the manifestation of bronzing or yellowing symptoms of rice cultivars.

  4. Irradiation of lettuce (Lactuca sativa. L.): microbiological and sensory aspects

    International Nuclear Information System (INIS)

    Tsuhako, Vanessa Provenzano

    2005-01-01

    The increasing demand for fresh foods have stimulated the marketing of minimally processed vegetables. However, these products maintain most of their natural microbiota even after being sanitized, including pathogenic microorganisms. Refrigerated storage allows the growth of psychotropic microorganisms and among them the pathogen Listeria monocytogenes. The ingestion of food contaminated with L. monocytogenes may represent a risk to pregnant women and their fetuses and to immunocompromised people. Non-thermal alternative processes for food preservation, such as irradiation, can reduce pathogenic and spoilage microorganism populations without impairing substantial changes in sensory, physical or chemical attributes. The aims of this research were to evaluate the effect of gamma radiation on L. monocytogenes artificially inoculated on minimally processed lettuce, to evaluate its effect on lettuce leaves through acceptance sensory test and to determine the irradiated vegetable shelf life through sensory and microbiological tests. A mixture of 4 types of lettuce (Iceberg, Boston, Loose-leaf and Red loose-leaf) were artificially inoculated with L. monocytogenes (7 log UFC/g lettuce) and then exposed to 0.3; 0.6; 0.9 and 1.2 kGy, under refrigeration. The DlO values for L. monocytogenes varied fram 0.18 to 0.21 kGy. Sensory and microbiological tests indicated that the shelf life of Iceberg lettuce stored at 7 deg C was 5 and 7 days for the irradiated and non-irradiated samples, respectively, and for the irradiated and non-irradiated Loose-leaf lettuce samples were 10 days. For the non-irradiated Boston sample, the shelf life was 3 days and for the Irradiated 7 days. Red loose-leaf showed 5 and 4 days of shelf lives for the irradiated and non-irradiated, respectively. Irradiated samples presented better microbiological quality than non-irradiated ones. The irradiation is feasible process to improve quality and safety of lettuce leaves. (author)

  5. Dormancy and cold hardiness transitions in wine grape cultivars Chardonnay and Cabernet Sauvignon

    Science.gov (United States)

    Dormancy and cold hardiness influence grapevine (Vitis vinifera L.) susceptibility to cold injury, which is a major cause of economic loss in high latitude growing regions. The objectives of this study were to compare dormancy and cold hardiness transitions in wine grape cultivars considered more (C...

  6. Impact of temperatures to Hessian Fly resistance of selected wheat cultivars in the Great Plains Region

    Science.gov (United States)

    Changes in temperature can result in fundamental changes in plant physiology. This study investigated the impact of different temperatures from 14 to 26 °C on the resistance or susceptibility to the Hessian fly, Mayetiola destructor, of selected wheat cultivars that are either currently popular in ...

  7. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

    International Nuclear Information System (INIS)

    Krizek, D.T.; Britz, S.J.; Mirecki, R.M.

    1998-01-01

    The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au)

  8. Inhibitory effects of ambient levels of solar UV-A and UV-B radiation in growth of cv. New Red Fire lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Krizek, D.T.; Britz, S.J.; Mirecki, R.M. [Climate Stress Laboratory, Beltsville, MD (United States)

    1998-05-01

    The influence of solar UV-A and UV-B radiation at Beltsville, MD, USA, on growth of Lactuca sativa L. (cv. New Red Fire lettuce) was examined during early summer of 1996 and 1997. Plants were grown from seed in plastic window boxes covered with Llumar to exclude UV-A and UV-B, polyester to exclude UV-B, or tefzel (1996) or teflon (1997) to transmit UV-A and UV-B radiation. After 31-34 days, plants grown in the absence of solar UV-B radiation (polyester) had 63 and 57% greater fresh weight and dry weight of tops, respectively, and 57, 72 and 47% greater dry weight of leaves, stems and roots, respectively, as compared to those grown under ambient UV-B (tefzel or teflon). Plants protected from UV-A radiation as well (Llumar) showed an additional 43 and 35% increase, respectively, in fresh and dry weight of tops and a 33 and 33% increase, respectively, in dry weight of leaves and stems, but no difference in root biomass over those grown under polyester. Excluding ambient UV-B (polyester) significantly reduced the UV absorbance of leaf extracts at 270, 300 and 330 nm (presumptive flavonoids) and the concentration of anthocyantins at 550 nm as compared to those of leaf extract from plants grown under ambient UV-A and UV-B. Additional removal of ambient UV-A (Llumar) reduced the concentration of anthocyanins, but had no further effect on UV absorbance at 270, 300 or 330 nm. These findings provide evidence that UV-B radiation is more important than UV-A radiation for flavonoid induction in this red-pigmented lettuce cultivar. Although previous workers have obtained decreases in lettuce yield under enhanced UV-B, this is the first evidence for inhibitory effects of solar UV-A and UV-B radiation on lettuce growth. (au) 34 refs.

  9. Carrot Cultivar Evaluation: Soilless Media vs. Hydroponics

    OpenAIRE

    Pinnock, Derek R.; Bugbee, Bruce

    2002-01-01

    Nine cultivars of carrots were grown in a growth chamber. Each cultivar was grown both in hydroponic and soil-less media root-zone for sixty days. Three 30L tubs were used for each root-zone treatment. Three cultivars were planted in each tub, initially at 180 plants m-2 then thinned to 90 plants m-2 on day 45.

  10. IPR 118 - Bread wheat cultivar

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Riede

    2007-01-01

    Full Text Available Wheat cultivar IPR 118 developed by IAPAR has a good yield potential and is widely adapted. It is earlymaturing and moderately tolerant to shattering and soil aluminum, moderately resistant to leaf rust and presents high glutenstrength for bread-making. The overall yield exceeded controls by 13%.

  11. BRS 374 – Wheat cultivar

    Directory of Open Access Journals (Sweden)

    Eduardo Caierão

    2013-01-01

    Full Text Available BRS 374 is a wheat cultivar developed by Embrapa. It resulted from a cross between the F1 generation of PF 88618/Coker80.33 and Frontana/Karl. BRS 374 belongs to the soft wheat class, has a low plant height, a high potential grain yield, andwhite flour.

  12. Detection of Lettuce Discoloration Using Hyperspectral Reflectance Imaging.

    Science.gov (United States)

    Mo, Changyeun; Kim, Giyoung; Lim, Jongguk; Kim, Moon S; Cho, Hyunjeong; Cho, Byoung-Kwan

    2015-11-20

    Rapid visible/near-infrared (VNIR) hyperspectral imaging methods, employing both a single waveband algorithm and multi-spectral algorithms, were developed in order to discrimination between sound and discolored lettuce. Reflectance spectra for sound and discolored lettuce surfaces were extracted from hyperspectral reflectance images obtained in the 400-1000 nm wavelength range. The optimal wavebands for discriminating between discolored and sound lettuce surfaces were determined using one-way analysis of variance. Multi-spectral imaging algorithms developed using ratio and subtraction functions resulted in enhanced classification accuracy of above 99.9% for discolored and sound areas on both adaxial and abaxial lettuce surfaces. Ratio imaging (RI) and subtraction imaging (SI) algorithms at wavelengths of 552/701 nm and 557-701 nm, respectively, exhibited better classification performances compared to results obtained for all possible two-waveband combinations. These results suggest that hyperspectral reflectance imaging techniques can potentially be used to discriminate between discolored and sound fresh-cut lettuce.

  13. Resposta de cultivares de algodoeiro a subdoses de glyphosate Response of cotton cultivars to reduced rates of glyphosate

    Directory of Open Access Journals (Sweden)

    O.M. Yamashita

    2005-12-01

    , BRS Facual, Antares and Coodetec 407. The plants were cultivated in plastic pots filled with soil substratum and kept under greenhouse conditions. Glyphosate application was performed 20 days post emergence, at which time they presented four true leaves. Reduced rates of glyphosate, simulating drift, ranged from 270 and 540 g. A control was also used, without herbicide application to compare the effects. Weekly evaluations were accomplished up to 42 days after application (DAA. During this period, plant height was also measured. Visual symptoms began 3 DAA, with the appearance of yellow spots at the tips of the youngest leaves, followed by withering at the apex of the plants. At the rate of 270 g ha-1, these symptoms showed low intensity but at the rate of 540 g ha-1 the symptoms caused "worrisome" to "very high'' toxicity, in most of the cases. BRS Facual and FM 986 were the most susceptible. Plant height was the most affected when the lowest glyphosate dose was applied. All cultivars treated with 270 g ha-1 glyphosate rate until 42 DAA were recovered. Fabrika, Coodetec 407, BRS Facual and ITA-90 cultivars, when treated with 540 g ha-1 glyphosate were more sensitive, presenting a height reduction between 84 and 90% 42 DAA. The less sensitive cultivars at the rate of 270 g ha-1 glyphosate were not the same at the 540 g ha-1 rate.

  14. Frequência de Lettuce big-vein associated virus e Mirafiori lettuce big-vein virus em Plantas de alface no Estado de São Paulo e transmissão através de extrato vegetal e solo Frequency of Lettuce big-vein associated virus and Mirafiori lettuce big-vein virus in symptomatic and assymptomatic lettuce plants and sap and soil transmission

    Directory of Open Access Journals (Sweden)

    Márcio Martinello Sanches

    2007-12-01

    Full Text Available A presença de sintomas de 'big vein' ou engrossamento das nervuras em alface e a associação do Lettuce big-vein associated virus (LBVaV e Mirafiori lettuce big-vein virus (MLBVV foram verificadas por RT-PCR utilizando-se oligonucleotídeos específicos para ambos os vírus. Foram coletadas 366 plantas sintomáticas nas regiões de Bauru, Campinas e Mogi das Cruzes no estado de São Paulo nos meses de junho e setembro de 2004 e abril e julho de 2005, e 18 plantas assintomáticas na região de Mogi das Cruzes no mês de dezembro de 2004. Infecção mista do LBVaV e MLBVV foi detectada em 76,2% das plantas sintomáticas, em 11,5% somente o MLBVV foi detectado e em 6,6% somente o LBVaV. Nas plantas assintomáticas coletadas em dezembro na região de Mogi das Cruzes, em áreas de alta incidência da doença durante o inverno, foi detectada a presença de MLBVV em 9 amostras e LBVaV em 7 amostras. Quatro dessas amostras apresentaram infecção mista, indicando que o desenvolvimento de sintomas depende de fatores abióticos, como temperatura. A inoculação via extrato vegetal a partir de plantas de alface com infecção mista pelo MLBVV e LBVaV foi realizada a 16°C/ 10°C (dia/noite e fotoperíodo de 11 horas, verificando-se que o MLBVV foi transmitido para Nicotiana tabacum TNN, N. rustica, N. occidentalis, Chenopodium quinoa e para as cultivares de alface Trocadero e White Boston, enquanto o LBVaV foi transmitido apenas para a alface White Boston. Entretanto, nenhuma destas plantas apresentou sintomas da doença, com exceção de C. quinoa que apresentou sintomas de lesões locais. Plantio em solo proveniente de áreas com histórico da doença de Mogi das Cruzes permitiu a transmissão do LBVaV para alface cv. White Boston e do MLBVV para alface cv. Trocadero e White Boston, embora apenas a cv. White Boston tenha apresentado sintomas da doença. Em conjunto, estes resultados demonstram a dificuldade de transmissão de ambos os vírus, mesmo em

  15. Genetic divergence of common bean cultivars.

    Science.gov (United States)

    Veloso, J S; Silva, W; Pinheiro, L R; Dos Santos, J B; Fonseca, N S; Euzebio, M P

    2015-09-22

    The aim of this study was to evaluate genetic divergence in the 'Carioca' (beige with brown stripes) common bean cultivar used by different institutions and in 16 other common bean cultivars used in the Rede Cooperativa de Pesquisa de Feijão (Cooperative Network of Common Bean Research), by using simple sequence repeats associated with agronomic traits that are highly distributed in the common bean genome. We evaluated 22 polymorphic loci using bulks containing DNA from 30 plants. There was genetic divergence among the Carioca cultivar provided by the institutions. Nevertheless, there was lower divergence among them than among the other cultivars. The cultivar used by Instituto Agronômico do Paraná was the most divergent in relation to the Carioca samples. The least divergence was observed among the samples used by Universidade Federal de Lavras and by Embrapa Arroz e Feijão. Of all the cultivars, 'CNFP 10104' and 'BRSMG Realce' showed the greatest dissimilarity. The cultivars were separated in two groups of greatest similarity using the Structure software. Genetic variation among cultivars was greater than the variation within or between the groups formed. This fact, together with the high estimate of heterozygosity observed and the genetic divergence of the samples of the Carioca cultivar in relation to the original provided by Instituto Agronômico de Campinas, indicates a mixture of cultivars. The high divergence among cultivars provides potential for the utilization of this genetic variability in plant breeding.

  16. MINERAL NUTRITION OF CRISPHEAD LETTUCE GROWN IN A HYDROPONIC SYSTEM WITH BRACKISH WATER

    Directory of Open Access Journals (Sweden)

    HAMMADY RAMALHO E SOARES

    2016-01-01

    Full Text Available Water availability in the Brazilian semiarid is restricted and often the only water source available has high salt concentrations. Hydroponics allows using these waters for production of various crops, including vegetables, however, the water salinity can cause nutritional disorders. Thus, two experiments were conducted in a greenhouse at the Department of Agricultural Engineering of the Federal Rural University of Pernambuco, to evaluate the effects of salinity on the mineral nutrition of crisphead lettuce, cultivar Taina, in a hydroponic system (Nutrient Film Technique, using brackish water in the nutrient solution, which was prepared by adding NaCl to the local water (0.2 dS m-1. A randomized blocks experimental design was used in both experiments. The treatments consisted of water of different salinity levels (0.2, 1.2, 2.2, 3.2, 4.2 and 5.2 dS m-1 with four replications, totaling 24 plots for each experiment. The water added to compensate for the water-depth loss due to evapotranspiration (WCET was the brackish water of each treatment in Experiment I and the local water without modifications in Experiment II. The increase in the salinity of the water used for the nutrient solution preparation reduced the foliar phosphorus and potassium contents and increased the chloride and sodium contents, regardless of the WCET. Foliar nitrogen, calcium, magnesium and sulfur contents were not affected by increasing the water salinity used for the nutrient solution preparation.

  17. Lettuce production in greenhouse under fertirrgation with nitrogen and potassium silicate

    Directory of Open Access Journals (Sweden)

    Renan Soares de Souza

    2017-04-01

    Full Text Available The objective of this study was to evaluate the effect of nitrogen and potassium silicate on the productive and commercial aspects of curly lettuce, Vera cultivar. The experimental design was completely randomized (CRD, with ten treatments and three replications. The treatments, arranged in a factorial design according to the Plan Puebla III matrix (Turrent & Laird, 1975, consisted of the combination of five doses of nitrogen (9; 54; 90; 126 and 171 kg ha-1 and five doses of potassium silicate (1.15; 6.90; 11.50; 16.10 and 21.85 kg ha-1. A control treatment without application of nitrogen and potassium silicate was also inserted. The crop was grown in a greenhouse and the doses were applied as sidedressing using drip micro-irrigation system. Total fresh matter, commercial fresh matter, non-commercial fresh matter, number of leaves and commercial trade index were evaluated. The commercial fresh matter and the number of commercial leaves per plant were affected only by nitrogen fertigation and increased linearly with the increase in the nitrogen dose of N, with the best responses observed at the highest dose of this element (171 kg ha-1. Potassium silicate had effect only in non-commercial fresh matter, not influencing the other characteristics.

  18. Genomic and environmental selection patterns in two distinct lettuce crop–wild hybrid crosses

    Science.gov (United States)

    Hartman, Yorike; Uwimana, Brigitte; Hooftman, Danny A P; Schranz, Michael E; van de Wiel, Clemens C M; Smulders, Marinus J M; Visser, Richard G F; van Tienderen, Peter H

    2013-01-01

    Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop–wild crosses of lettuce. We performed quantitative trait loci (QTL) analyses and estimated the fitness distribution of early- and late-generation hybrids. We detected consistent results across field sites and crosses for a fitness QTL at linkage group 7, where a selective advantage was conferred by the wild allele. Two fitness QTL were detected on linkage group 5 and 6, which were unique to one of the crop–wild crosses. Average hybrid fitness was lower than the fitness of the wild parent, but several hybrid lineages outperformed the wild parent, especially in a novel habitat for the wild type. In early-generation hybrids, this may partly be due to heterosis effects, whereas in late-generation hybrids transgressive segregation played a major role. The study of genomic selection patterns can identify crop genomic regions under negative selection across multiple environments and cultivar–wild crosses that might be applicable in transgene mitigation strategies. At the same time, results were cultivar-specific, so that a case-by-case environmental risk assessment is still necessary, decreasing its general applicability. PMID:23789025

  19. Effect of the culture filtrate of Pseudocercospora fijiensis Morelet on adventitious buds of Musa spp. cultivars

    Directory of Open Access Journals (Sweden)

    Lourdes R. García

    2004-01-01

    Full Text Available The obtaining of bananas tolerant or resistant to the Black Sigatoka (Mycosphaerella fijiensis Morelet is an imperious need since 1991 with its apparition in our country. The effect of the culture filtrate was studied on different strain of the fungus on adventitious buds of the cultivar Grande Naine (AAA (susceptible and Pellipita (ABB (resistant with the objective of determining possible differences between these cultivars the most effective strain and the optimum dilution. Adventitious buds of these cultivars formed in a cultivation medium with high concentrations of 6 BAP were utilized and then they were subcultivated on the selective medium that contained different dilutions of culture filtrate of the strains C-27, C-21, and C-19. It was evaluated at 15 and 30 days the fresh weight increment of the explants and the percentage of growth and mortality, being found differences between the susceptible cultivar and the resistant one with the most concentrated dilutions. The best results of differentiation were obtained with the dilution 1:5 The strains studied showed different effects on the explants. Significant differences were founded when C-21 and C-19 were used, not been so with the C-27. Growth stimulation was observed in both cultivars in the control treatment that contained the components of the fungus culture medium, discarding so any type of toxicity of these substances on the adventitious buds that could disguise the results. key words: Black Sigatoka, in vitro selection, Mycosphaerella fijiensis Morelet, strains, tissue culture

  20. Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

    Science.gov (United States)

    Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

    2017-06-01

    Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

  1. Evaluation of physiological and defense characteristics and ions contents of Red and Brooms cultivars of sorghum (Sorghum biolor under salt stress stress in vitro

    Directory of Open Access Journals (Sweden)

    Roya Razavizadeh

    2016-12-01

    Full Text Available The present study was conducted to evaluate defense and physiological responses of some red and broomscultivars of Sorghum to salinity stress under in vitro culture. Seeds of Sorghum cultivars were cultured on MS (Murashig and Skoog, 1962 medium containing 0, 50, 100 and 150 mM NaCl under in vitro condition. After 2 weeks, the effect of salinity was studied on percentage of germination, growth parameters, photosynthetic capacity (total chlorophyll and carotenoids, total anthocyanin, total felavonoids, reducing sugars, proline, Na+/K+/Ca2+ ions, total soluble protein content, ascorbate peroxidase and catalase activities in roots and shoots. According to percentage of seed germination and growth parameters, Red and brooms cultivars were selected as susceptible and resistant to salinity in the study, respectively. The photosynthetic pigments (chlorophyll and carotenoids and the anthocyanin content decreased by increasing salt levels in both cultivars, while flavonoids increased in three wavelengths 270, 300 and 330 nm. The results showed proline, suger and protein contents increased in roots and shoots of two cultivars by increasing salinity. The content of Na+ ion increased in the roots of red and brooms cultivars and shoot of Red cultivar. Ratio Na/K increased in roots of two cultivars and shoots of red by increasing salinity. Ratio Na/K in the shoots of brooms cultivar didn’t change significantly under salt stress. Generally in the presence of salt, potassium decreased in roots and shoots of two cultivars. Calcium ion amount in the roots of two cultivars didn’t change significantly under salt stress while it increased in shoots of two cultivars. The CAT activity increased in roots and shoots of two cultivars but APX activity increased in brooms cultivar and decreased significantly in red cultivar.

  2. Growth experiment in lettuce [Lactuca sativa] using laser light

    International Nuclear Information System (INIS)

    Mori, Y.; Takatsuji, M.

    2001-01-01

    Photosynthetic rate, relative growth rate and vitamin C contents were measured in lettuce cultivated under red and blue lasers and the results were compared with those cultivated under light emitting diodes (LED). It was found that lettuce grew fairly healthily under red laser diode (650 nm) and blue laser (442 nm) with R/B ratio 10. However, both photosynthetic rate and growth rate rather diminished compared with LED cases. As for vitamin C contents, the result was about the same as LED cases

  3. BRS Ana: cultivar de batata de duplo propósito BRS ANA: A dual purpose potato cultivar

    Directory of Open Access Journals (Sweden)

    Arione da S Pereira

    2010-12-01

    potential for processing into frozen French fries and flakes, released in 2007. It was developed by the Embrapa Potato Breeding Program (Embrapa Temperate Agriculture, Pelotas-RS; Embrapa Transference of Technology, Office of Canoinhas-SC; and Embrapa Vegetables, Brasília-DF, based on tuber appearance and yield, specific gravity and French fries quality. Tubers are red-skinned, lightly rough, oval shaped with shallow eyes. The pulp is white. Cultivar BRS Ana has high yield potential. In the subtropical ecosystem, cultivar BRS Ana showed higher yield (31.2 t ha-1 than the most used cultivars in Brazil when grown in autumn, and did not differ from them in the spring. In the tropical ecosystem, under irrigation, BRS Ana did not differ from both control cultivars. It produced higher percentage of marketable tubers (55.6% and average tuber weight (108.4 g than the controls in the fall crop of subtropical ecosystem. In both ecosystems, cultivar BRS Ana presented high specific gravity (1.086 and dry matter content (19.7%. The sensorial analysis showed that cultivar BRS Ana is adequate for home made French fries as well as for industrial processing. It is moderately susceptible to late blight (Phytophthora infestans and presents good resistance to early blight (Alternaria solani. The reaction to the tuber soft rot (Pectobacterium sp. is similar to the most used cultivars. It has low seed degeneration conferred by moderate resistance to PVY and low incidence of PLRV. Susceptibility to tuber physiological disorders has not been observed. It seems that BRS Ana has lower fertilizer and water requirements than the most planted cultivars, meaning reduction of crop cost and risk. In the subtropical ecosystem, tuberization starts later in spring, therefore BRS Ana should be planted earlier in the season.

  4. Cytomorphological characterization of tea cultivars

    International Nuclear Information System (INIS)

    Rahman, H.; Khalil, I.H.; Shah, S.M.A.; Khanzada, T.Z.; Abbasi, F.M; Ahmad, H.; Shah, Z.

    2010-01-01

    Cytomorphological characterization was performed on tea cultivars, three each of Camellia sinensis and Camellia assamica species. For plant morphological study, one and a half year old healthy shoots were obtained from the selected mother bushes of the six tea cultivars. The field experiment conducted in randomized complete block design having four replications was aimed at evaluating plant height, number of leaves plant-l, number of branches plant-l, number of flowers plant-1, fresh and dry leaf weight plant-I. The data indicated significant difference between the two species with narrow leaved cultivars having increased plant height, number of leaves and branches plant-I than the broad leaved cultivars, but less number of flowers plant-l, fresh and dry leaf weight. Karyotype analysis indicated that both the groups are diploid with 2n = 30. On the basis of chromosome morphology, C. assamica had larger chromosomes (3-10.5 mu m) as compared to C. sinensis (3.9-8 mu m). C. assamica has relatively advanced features as compared to C. sinensis. However, both the groups possessed mostly median to sub-median centromeres with no secondary constrictions which possibly indicates that little or no evolutionary changes have taken place in tea and that the karyotype is still at a primitive stage, with C. sinensis being more primitive than C. assamica. Our results suggest that both the groups are different from each other in morphological as well as cytological attributes and could therefore generate more germplasm if the two species could be involved in tea breeding programs. (author)

  5. Molecular characterisation of radish cultivars

    Directory of Open Access Journals (Sweden)

    Sara Michelly Cruz

    Full Text Available The radish has been gaining importance in the Brazilian market due to its use as a green manure and cover crop, and also due to its potential for the production of biodiesel, however there are only two registered cultivars, which are morphologically very similar. Determination of genetic purity is a prerequisite in marketing seeds as it ensures uniformity of the crop and is important in breeding programs. The aim of this work therefore was to evaluate the similarity and genotype patterns which permit differentiation of the commercial radish cultivars IPR 116 and CATI AL-1000. In order to do this, isoenzyme electrophoretic patterns were analysed in dry seeds, soaked seeds, seedling leaves and young leaves; the isoenzymes used being: superoxide dismutase, catalase, esterase, glutamate-oxalocetate, malate dehydrogenase and isocitrate lyase. Thirty-seven RAPD primers and 10 ISSR primers in leaves of the CATI AL-1000 and IPR-116 cultivars were analysed. Among the isoenzymes under study, the most polymorphic were glutamate oxalocetate, malate dehydrogenase, esterase and superoxide dismutase, with the superoxide dismutase system giving the best characterisation for all stages of development. The catalase isoenzyme system did not make it possible to differentiate between cultivars at any stage of development, and isocitrate lyase was not revealed by the protocol used. In analysis of the markers, 27 RAPD primers and eight ISSR primers showed polymorphism. The results indicate that it is possible to determine reliable descriptors based on isoenzymes at different stages of development of the radish and with the use of RAPD and ISSR primers.

  6. Influence of nutrient solutions in an open-field soilless system on the quality characteristics and shelf life of fresh-cut red and green lettuces (Lactuca sativa L.) in different seasons.

    Science.gov (United States)

    Luna, María C; Martínez-Sánchez, Ascensión; Selma, María V; Tudela, Juan A; Baixauli, Carlos; Gil, María I

    2013-01-01

    Little information is available about the impact of nutrient solution ion concentration on quality characteristics and shelf life of fresh-cut lettuce grown in soilless systems in open field. Three lettuce genotypes, lollo rosso and red oak leaf as red-leafed genotypes and butterhead as green-leafed genotype, were studied. The influence of three nutrient solutions with low, medium and high ion concentrations, which varied in the macroanion (NO₃⁻) and macrocations (K⁺, Ca²⁺ and NH₄⁺), were compared in summer and winter. The nutrient solutions evaluated in this study for the production of lettuce in a soilless system did not strongly influence the quality characteristics of the raw material. When the ion concentration of the nutrient solution was increased, fresh weight decreased, although it depended on the genotype and season. Maturity index and dry matter content varied with the season but independently of the nutrient solution. In summer, maturity index was higher and dry matter lower than in winter. Initial texture and visual quality were not influenced by the nutrient solution. Medium ion concentration provided the highest content of vitamin C and phenolic compounds. Our observations pointed out that the genotype had a strong influence on the shelf life of the fresh-cut product with minor differences among nutrient solutions. In general, red-leafed lettuces showed the highest antioxidant content, helping the maintenance of sensory characteristics throughout storage. The combination of optimal nutrient solution ion concentration and suitable cultivar is considered essential to ensure lettuce post-cutting life. Copyright © 2012 Society of Chemical Industry.

  7. Activity of aphids associated with lettuce and broccoli in Spain and their efficiency as vectors of Lettuce mosaic virus.

    Science.gov (United States)

    Nebreda, M; Moreno, A; Pérez, N; Palacios, I; Seco-Fernández, V; Fereres, A

    2004-03-01

    This research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in Spain, and to determine their population dynamics and ability to transmit Lettuce mosaic virus (LMV). Green tile traps and Moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. Aphid species feeding on lettuce were counted weekly. The transmission efficiencies of LMV were determined for the aphid species caught most frequently. The Moericke traps generally caught more aphid species than the tile trap, but the latter was the most suitable to estimate flight activity of species involved in virus spread. Spring aphid catches indicated that the main aphid species landing on lettuce in the regions of Madrid and Murcia was Hyperomyzus lactucae, but Brachycaudus helichrysi was also abundant in both regions. In broccoli in the Navarra region, the most abundant species in spring were Aphis fabae, B. helichrysi and H. lactucae. In autumn-sown crops, the main species landing on lettuce in the Madrid region were Hyadaphis coriandri and Aphis spiraecola. In Murcia, A. spiraecola and Myzus persicae were the most abundant, while in Navarra, Therioaphis trifolii, and various Aphis spp. were the most numerous landing on broccoli. The main aphid species colonising lettuce was Nasonovia ribisnigri, but other less abundant colonising species were Aulacorthum solani and Macrosiphum euphorbiae. The most efficient vectors of LMV were M. persicae, Aphis gossypii and M. euphorbiae, while A. fabae and H. lactucae transmitted with low efficiency, and Rhopalosiphum padi and N. ribisnigri did not transmit. Occurrence of LMV epidemics in central Spain in relation to aphid flights and the role of weeds as virus reservoirs is discussed.

  8. Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

    Science.gov (United States)

    The contamination of lettuce, spinach and basil with pathogenic E. coli has caused numerous illnesses over the past decade. E. coli O157:H7, E. coli O104:H4 and avian pathogenic E. coli (APECstx- and APECstx+) were inoculated on basil plants and in promix soiless substrate using drip and overhead ir...

  9. Genetic transformation of lettuce ( Lactuca sativa ): A review | Dan ...

    African Journals Online (AJOL)

    Lettuce (Lactuca sativa L.) is a globally important leafy vegetable that can be grown worldwide. Due to the rapid growth of population and the human desire to progress, there have been a lot of studies made by researchers, especially in genetic engineering. Improvements in regeneration system and transformation ...

  10. The nicolet lettuce model : a theme with variations

    NARCIS (Netherlands)

    Seginer, I.; Linker, F.; Buwalda, F.; Straten, van G.

    2004-01-01

    The NICOLET model has been developed to predict the growth and nitrate content of greenhouse lettuce. Four single-organ versions have been developed: [1] abundant supply of nitrogen (1998), [2] mild N-stress (1999), [3] severe N-stress (2003), and [4] ontogenetic changes of organic-N and water

  11. Irrigation and nitrogen level affect lettuce yield in greenhouse ...

    African Journals Online (AJOL)

    This study was conducted to investigate the effect of different irrigation and nitrogen levels on lettuce yield characteristics in greenhouse condition from December 2006 to March 2007. Irrigation levels of 100% of total class A pan (S1), 80% of total class A pan (S2), 60% of total class A pan (S3) and nitrogen levels of 0 kg ...

  12. Post-harvest decay in fresh-cut lettuce

    Science.gov (United States)

    Shelf-life of fresh-cut lettuce was assessed in two mapping population (Salinas 88 x La Brillante, and Pavane x Parade. The most significant QTL was detected in both populations on linkage group 4. This QTL was detected in seven experiments grown in different environments. Molecular markers are bein...

  13. Listeria monocytogenes internalizes in Romaine Lettuce grown in greenhouse conditions

    Science.gov (United States)

    Listeria monocytogenes has been implicated in a number of outbreaks involving fresh produce, including an outbreak in 2016 resulting from contaminated packaged salads. The persistence and internalization potential of L. monocytogenes in romaine lettuce was evaluated, and the persistence of two L. mo...

  14. Unravelling the resistance mechanism of lettuce against Nasonovia ribisnigri

    NARCIS (Netherlands)

    Broeke, ten C.J.M.

    2013-01-01

    Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically

  15. University Opinion Poll 9: Child Care, MPIRG, Lettuce. Preliminary Report.

    Science.gov (United States)

    Matross, Ronald; And Others

    The University Opinion Poll conducted a survey of student opinion on issues related to University-sponsored day care, the role of the Minnesota Public Interest Research Group (MPIRG) and the University's policy on buying lettuce for its food services. Four hundred fifty-two respondents, 76% of a random sample of University of Minnesota students,…

  16. Outbreaks of gastroenteritis linked to lettuce, Denmark, January 2010

    DEFF Research Database (Denmark)

    Ethelberg, S.; Lisby, M.; Bottiger, B.

    2010-01-01

    At least 11 linked outbreaks of gastroenteritis with a total of 260 cases have occurred in Denmark in mid January 2010. Investigations showed that the outbreaks were caused by norovirus of several genotypes and by enterotoxigenic Escherichia coli. Lettuce of the lollo bionda type grown in France...

  17. Characterization and performance of 16 new inbred lines of lettuce

    Science.gov (United States)

    The Agricultural Research Service, U.S. Department of Agriculture announces the release of sixteen breeding lines of lettuce (Lactuca sativa L.). Five (SM13-I1, SM13-I2, SM13-I3, SM13-I4, and SM13-I5) of the six iceberg breeding lines can be used for whole head or salad blend production; the sixth i...

  18. Seed Production of Cutting Lettuce Varieties: Economical Facets

    Directory of Open Access Journals (Sweden)

    Н. В. Лещук

    2011-05-01

    Full Text Available The article highlights current problems of cutting lettuce seed production for all its variants. Research background is provided to the composition of material expenditures for growing of every variant in particular. Economical efficiency of seed production in line with varietal certification requirements has been reproved.

  19. "Lettuce" Learn Math: Teaching Mathematics with Seeds and Centimeters

    Science.gov (United States)

    Rickard, Laura N.; Wilson, Colette

    2006-01-01

    "Lettuce Learn Math" is an interdisciplinary program that has effectively linked a small-scale agricultural production system to a sixth-grade mathematics and science curriculum. The mathematical concepts and skills, including measurement and geometry, taught in this project met and often exceeded the standards set by New York state for…

  20. Stable plastid transformation in lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Lelivelt, Cilia L C; McCabe, Matthew S; Newell, Christine A; Desnoo, C Bastiaan; van Dun, Kees M P; Birch-Machin, Ian; Gray, John C; Mills, Kingston H G; Nugent, Jacqueline M

    2005-08-01

    Although plastid transformation in higher plants was first demonstrated in the early 1990s it is only recently that the technology is being extended to a broader range of species. To date, the production of fertile transplastomic plants has been reported for tobacco, tomato, petunia, soybean, cotton and Lesquerella fendleri (Brassicaceae). In this study we demonstrate a polyethylene glycol-mediated plastid transformation system for lettuce that generates fertile, homoplasmic, plastid-transformed lines. Transformation was achieved using a vector that targets genes to the trnA/trnI intergenic region of the lettuce plastid genome employing the aadA gene as a selectable marker against spectinomycin. Spectinomycin resistance and heterologous gene transcription were shown in T(1) plants derived from self-pollinated primary regenerants demonstrating transmission of the plastid-encoded transgene to the first seed generation. Crossing with male sterile wild-type lettuce showed that spectinomycin resistance was not transmitted via pollen. Constructs containing the gfp gene showed plastid-based expression of green fluorescent protein. The lettuce plastid could have potential both as a production and a delivery system for edible human therapeutic proteins.

  1. The resistance of lettuce to the aphid Nasonovia ribisnigri

    NARCIS (Netherlands)

    Helden, van M.

    1995-01-01

    The resistance of lettuce to the aphid Nasonovia ribisnigri is based on a single, dominant gene, the Nr-gene. On the resistant plant aphids died within a few days, without any honeydew production. Transfer-experiments with a short stay on a resistant plant followed by a

  2. Determining the Pollinizer for Pecan Cultivars

    Directory of Open Access Journals (Sweden)

    Fereidoon Ajamgard

    2017-05-01

    Full Text Available This study was conducted to determine the best pollinizer for five selected pecan cultivars in southwest of Iran at Safiabad Agricultural Research Center in 2014-2015. The cultivars included: 'GraTex', '10J', 'Wichita 6J', 'GraKing', 'Choctaw' as pollinated cultivars (♀ and 'GraTex', 'Peruque', 'Comanche 4M', '10J', 'Wichita 6J', 'Mohawk', 'Mahan', 'Stuart 2J', '3J', 'Stuart 4J', 'GraKing', 'Choctaw', 'Apache', '6M', 'Wichita 7J' and 'Comanche 5M.' as pollinizer cultivars (♂. In the first step, a pollination chart of cultivars was determined in two years. The pollination chart of cultivars showed that all the cultivars investigated during this study were dichogamous and also protogynous except for the 'Peruque'. ‘GraKing’ had the longest duration of shedding pollen. Pollination chart showed that 'Peruque', ‘GraKing’, and 'Stuart 2J' had flowering overlap with the selected cultivars. Pollen germination test showed that the germination ability was different among the cultivars. It was 45% for 'GraKing' and 35% for 'Peruque', which were both recommended as pollinizers in this study. '6M', 'GraTex' and 'Stuart 4J' cultivars had the highest pollen germination percentage of 65%, 60% and 60%, respectively. The results of controlled pollinationtest showed that different pollen sources had no significant effect on nuts per cluster but self-pollinated all of the cultivars significantly reduced fruit set in first and second years. Based on the present research, pollination in pecan orchard was necessary for adequate yield. Also, 'Peruque', 'GraKing' and 'Stuart 2J' were the best pollinizers for five selected cultivars in southwest of Iran.

  3. NS Pudarka: A new winter wheat cultivar

    Directory of Open Access Journals (Sweden)

    Hristov Nikola

    2014-01-01

    Full Text Available The high-yielding, medium late winter wheat cultivar NS Pudarka was developed by crossing genetic divergent parents: line NMNH-07 and cv. NS 40S and Simonida. In cultivar NS Pudarka genes responsible for high yield potential, very good technological quality, resistance to lodging, low temperature and diseases, were successfully combined. It was registered by Ministry of agriculture, forestry and water management of Serbia Republic in 2013. This cultivar has wide adaptability and stability of yield that enable growing in different environments with optimal agricultural practice. On the base of technological quality this cultivar belongs to the second quality class, A2 farinograph subgroup and second technological group.

  4. Migration Monitoring of Blackcurrant Gall Mite (Cecidophyopsis ribis Westw. from Buds to Leaves on Several Blackcurrant (Ribes nigrum L. Cultivars

    Directory of Open Access Journals (Sweden)

    Piotrowski Wojciech

    2016-12-01

    Full Text Available The blackcurrant gall mite (Cecidophyopsis ribis is the most important pest of blackcurrant crops. Over recent years withdrawal from plant protection programmes of chemical products (endosulfan and amitraz used for the control of this pest in Poland, has led to an observed increase in population numbers. In 2013, fenpiroxymate (Ortus 05 SC became registered for control of this pest. It is deemed best that chemical protection should be used during the migration period; when big gall mites emerge from buds in search of new buds. The studies were carried out in a plantation of blackcurrants during 2011-2013. The assessment of migration of the blackcurrant gall mite was carried out on the cultivars ‘Ben Hope’, ‘Ben Alde’r, ‘Ojeby’n and ‘Ruben’. Every year, from selected cultivars buds were collected. They were then placed on blackcurrant leaves within Petri dishes. After one, three and five days of placing buds on the leaves, the estimated number of eriophyid mites on the leaves was calculated. The data has shown a very useful method for monitoring blackcurrant gall mite, which can be used in calculating the treatment dates for this pest. Also, the data has shown that differences in the periods of migration of the mite are dependent on the cultivar and time of flowering. Among the cultivars observed the least susceptible to colonization by the blackcurrant gall mite was a Polish cultivar ‘Ruben’, while the most susceptible cultivar was ‘Ben Hope’.

  5. Induced mutation breeding in Cassava (Manihot esculenta Crantz) cultivar `Bosom Nsia`

    Energy Technology Data Exchange (ETDEWEB)

    Ahiabu, R K.A.; Klu, G Y.P. [Biotechnology and Nuclear Agricultural Research Inst., Ghana Atomic Energy Commission, Legon (Ghana)

    1997-12-01

    Cassava is one of the most important staple food crops in the lowland tropics. In most cassava producing countries, it is mainly utilized for human consumption. Cassava leaves are a good source of protein and vitamins, and are used as food in Africa. In Ghana, `Bosom Nsia` is one of the most widely grown cultivars probably because of its good cooking quality and fast maturation in six months. However, this cultivar is highly susceptible to cassava mosaic virus disease (CMV), hence the need to improve its resistance to the disease. Various in vitro techniques have been developed for cassava research, Klu and Lamptey reported irradiation doses of 25 and 30 Gy to be ideal for in vitro mutagenesis of cassava. These doses were applied to in vivo and in vitro mutation for breeding CMV resistance in the cultivar `Bosom Nsia`. 6 refs.

  6. Induced mutation breeding in Cassava (Manihot esculenta Crantz) cultivar 'Bosom Nsia'

    International Nuclear Information System (INIS)

    Ahiabu, R.K.A.; Klu, G.Y.P.

    1997-01-01

    Cassava is one of the most important staple food crops in the lowland tropics. In most cassava producing countries, it is mainly utilized for human consumption. Cassava leaves are a good source of protein and vitamins, and are used as food in Africa. In Ghana, 'Bosom Nsia' is one of the most widely grown cultivars probably because of its good cooking quality and fast maturation in six months. However, this cultivar is highly susceptible to cassava mosaic virus disease (CMV), hence the need to improve its resistance to the disease. Various in vitro techniques have been developed for cassava research, Klu and Lamptey reported irradiation doses of 25 and 30 Gy to be ideal for in vitro mutagenesis of cassava. These doses were applied to in vivo and in vitro mutation for breeding CMV resistance in the cultivar 'Bosom Nsia'. 6 refs

  7. Critical osmotic, ionic and physiological indicators of salinity tolerance in cotton (gossypium hirsutum l.) for cultivar selection

    International Nuclear Information System (INIS)

    Munis, M.F.H.; Tu, L.; Ziaf, K; Tan, J.; Deng, F.; Zhang, X.

    2010-01-01

    Salinity affects the germination, growth and ultimately the yield of cotton (Gossypium hirsutum L.) which demands reliable traits for the evaluation and selection of salt tolerant cultivars. Here, ten major osmotic, ionic and physiological parameters have been studied to distinguish the effect of salinity in two different cultivars of cotton. Plants were grown in hydroponic system and exposed to different salinity levels of NaCl followed by its recovery under non saline conditions. Data was recorded at three different stages i.e., before stress, after stress and after recovery for comparative study. Recovery assay proved to be very helpful in extracting reliable results. Both cultivars showed significantly different response to Na+ and K+ accumulation and phenotypically salt tolerant cultivar (Coker 312) accumulated less Na+ and more K+ in comparison with susceptible (Simian 3). Decrease in leaf area, seed germination and seedling growth were also conclusive to differentiate these cultivars. We also found other physiological parameters like relative leaf water content (RLWC), plant fresh-weight (PFW), plant dry-weight (PDW), relative growth rate (RGR) and stomatal behavior as good indicators of salinity but could not find their significant role to differentiate two closely relevant cultivars regarding salinity tolerance. Our studies revealed that proline accumulation and chlorophyll concentration are not significant to be used as accurate indicators to characterize the sensitivity of cotton cultivars to salinity. We found post-recovery analysis to be very useful in understanding the role and behavior of different indicators of salinity. (author)

  8. Cannabis - from cultivar to chemovar.

    Science.gov (United States)

    Hazekamp, A; Fischedick, J T

    2012-01-01

    The medicinal use of Cannabis is increasing as countries worldwide are setting up official programs to provide patients with access to safe sources of medicinal-grade Cannabis. An important question that remains to be answered is which of the many varieties of Cannabis should be made available for medicinal use. Drug varieties of Cannabis are commonly distinguished through the use of popular names, with a major distinction being made between Indica and Sativa types. Although more than 700 different cultivars have already been described, it is unclear whether such classification reflects any relevant differences in chemical composition. Some attempts have been made to classify Cannabis varieties based on chemical composition, but they have mainly been useful for forensic applications, distinguishing drug varieties, with high THC content, from the non-drug hemp varieties. The biologically active terpenoids have not been included in these approaches. For a clearer understanding of the medicinal properties of the Cannabis plant, a better classification system, based on a range of potentially active constituents, is needed. The cannabinoids and terpenoids, present in high concentrations in Cannabis flowers, are the main candidates. In this study, we compared cultivars obtained from multiple sources. Based on the analysis of 28 major compounds present in these samples, followed by principal component analysis (PCA) of the quantitative data, we were able to identify the Cannabis constituents that defined the samples into distinct chemovar groups. The study indicates the usefulness of a PCA approach for chemotaxonomic classification of Cannabis varieties. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Zinc fertilization in cowpea cultivars

    Directory of Open Access Journals (Sweden)

    Francisco de Brito Melo

    Full Text Available ABSTRACT Zinc (Zn is an essential micronutrient for plants, due to its role as a functional, structural, or regulatory cofactor in a large number of enzymes. The element is necessary for the synthesis of tryptophan, which is a precursor of indoleacetic acid. The aim of this study was to evaluate the behavior of two cowpea cultivars fertilized with four doses of Zn (0.0, 2.0, 4.0, and 6.0 kg of Zn ha-1 regarding dry grain yield (PGS, in addition to quantifying leaf and grain Zn content and grain crude protein. The experiment was conducted in the town of Brejo, in the state of Maranhão, Brazil. A 4 x 2 factorial scheme was used with four replications. Response functions were adjusted by calculating the Zn doses which provided a maximum technical efficiency for each genotype. The tested cultivars of cowpea showed no great difference regarding Zn demand applied to the soil, ranging from 3.2 to 3.4 kg of Zn ha-1 for BRS Tumucumaque and BRS Guariba, respectively. Concerning Zn use efficiency, BRS Guariba was more responsive than was BRS Tumucumaque, i.e. the same dose of Zn produced 70 kg grain and 2.1 kg crude protein per hectare.

  10. Developing native Vaccinium crops and cultivars

    Science.gov (United States)

    Vaccinium species have long been harvested from the wild. Breeding and cultivar development, however, did not begin until about 1911 in New Jersey with efforts to commercially cultivate northern highbush blueberry (Vaccinium corymbosum). Cultivar development spread to cranberry (V. macrocarpon) and ...

  11. Effects of Soybean Cultivars on Soymilk Quality

    Directory of Open Access Journals (Sweden)

    Aziadekey, M.

    2001-01-01

    Full Text Available Soymilk was prepared from twelve soybean cultivars grown under the same environmental conditions to evaluate their effects on soymilk characteristics. Significant correlations were observed between the Chemical composition of the seeds and the resultant soymilk. Soymilk solids were significantly affected by seed size and seed phosphorus contents. Cultivars with dark hilum produced soymilk with less attractive colour.

  12. Inheritance and genetic mapping of resistance to Asian soybean rust in cultivar TMG 803

    Directory of Open Access Journals (Sweden)

    Éder Matsuo

    2014-11-01

    Full Text Available This study analyzed the inheritance and identified microsatellite markers linked to the resistance gene to Phakopsora pachyrhizi in soybean cultivar TMG 803. Hybridization between the cultivars TMG 803 and BRS Valiosa RR was performed to obtain F1 progenies and the F2 population. The response of the parents ‘TMG 803’ and ‘BRS Valiosa RR’ to P. pachyrhizi was, respectively, resistant and susceptible, and among the 116 F2 plants, 93 were resistant and 23 susceptible, under natural infection and field conditions. It was found that the resistance of cultivar TMG 803 is controlled by one gene with complete dominance, mapped as resistance locus Rpp4 of linkage group G. Of the 16 tested, one microsatellite marker, sc21_3420, was completely linked to the resistance gene (distance 0.0cM and the favorable allelic form was present in cultivar TMG 803, which may therefore be useful in assisted selection in segregating populations.

  13. Nutritional and taste characteristics of low-potassium lettuce developed for patients with chronic kidney diseases

    OpenAIRE

    Yoshida, Takuya; Sakuma, Kozue; Kumagai, Hiromichi

    2014-01-01

    Dietary potassium restriction is recommended for chronic kidney disease (CKD) patients with hyperkalemia. Boiling or soaking vegetables in water is known to decrease their potassium content. However, these methods can also reduce the quantity of other nutrients. Recently, low-potassium (LK) lettuce has been developed for CKD patients with hyperkalemia. This study compared the potassium content, other nutritional values, and taste characteristics of LK lettuce with those of normal lettuce. The...

  14. Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

    OpenAIRE

    Zhang, N.

    2008-01-01

    Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29 Backcross Inbred Lines (BILs) representing in total 96% of the L. saligna genome, 15 introgressions were identified to contribute to this resistance at one to four tested lettuce developmental stages and ...

  15. Plastid transformation in lettuce (Lactuca sativa L.) by biolistic DNA delivery.

    Science.gov (United States)

    Ruhlman, Tracey A

    2014-01-01

    The interest in producing pharmaceutical proteins in a nontoxic plant host has led to the development of an approach to express such proteins in transplastomic lettuce (Lactuca sativa L.). A number of therapeutic proteins and vaccine antigen candidates have been stably integrated into the lettuce plastid genome using biolistic DNA delivery. High levels of accumulation and retention of biological activity suggest that lettuce may provide an ideal platform for the production of biopharmaceuticals.

  16. Sensitivity of tomato cultivars to sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Howe, T.K.; Woltz, S.S.

    1982-04-01

    The sensitivity of 26 cultivars of tomato (Lycopersicon esculentum Mill.) were compared at 2 concentrations of SO/sub 2/in specially designed exposure greenhouses. Cultivars studied included fresh market, processing, and specialty types. Insensitive and sensitive cultivars were identified by assessment of acute SO/sub 2/-induced foliar necrosis. Cultivars found to be insensitive to SO/sub 2/ included: 'Ace', 'Bonanza', 'Heinz 1350', 'Tarquinia Tondino', and 'VF 145-B 7879'. Cultivars found to be sensitive to SO/sub 2/ included: 'Bellarina', 'Chico III', 'Flora-Dade', 'Red Cherry Large' 'Sub-Arctic Delight', and 'Vetomold. 10 figures, 1 table.

  17. Differential response of wheat cultivars to Pseudomonas brassicacearum and take-all decline soil.

    Science.gov (United States)

    Yang, Mingming; Mavrodi, Dmitri; Thomashow, Linda S; Weller, David M

    2018-06-15

    2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. in the P. fluorescens complex are primarily responsible for a natural suppression of take-all of wheat known as take-all decline (TAD) in many fields in the USA. P. brassicacearum, the most common DAPG producer found in TAD soils in the Pacific Northwest (PNW) of the USA, has biocontrol, growth promoting and phytotoxic activities. In this study, we explored how the wheat cultivar affects the level of take-all suppression when grown in a TAD soil, and how cultivars respond to colonization by P. brassicacearum. Three cvs. Tara, Finley and Buchanan supported similar rhizosphere population sizes of P. brassicacearum when grown in a TAD soil, however they developed significantly different amounts of take-all. Cultivars Tara and Buchanan developed the least and most take-all, respectively, and Finley showed an intermediate amount of disease. However, when grown in TAD soil that was pasteurized to eliminate both DAPG producers and take-all suppression, all three cultivars were equally susceptible to take-all. The three cultivars also responded differently to the colonization and phytotoxicity of P. brassicacearum strains Q8r1-96 and L5.1-96, which are characteristic of DAPG producers in PNW TAD soils. As compared to cv. Tara, cv. Buchanan showed significantly reduced seedling emergence and root growth when colonized by P. brassicacearum, and the response of Finley was intermediate. However, all cultivars emerged equally when treated with a DAPG-deficient mutant of Q8r1-96. Our results indicate that wheat cultivars grown in a TAD soil modulate both the robustness of take-all suppression and the potential phytotoxicity of the antibiotic DAPG.

  18. Pea weevil damage and chemical characteristics of pea cultivars determining their resistance to Bruchus pisorum L.

    Science.gov (United States)

    Nikolova, I

    2016-04-01

    Bruchus pisorum (L.) is one of the most intractable pest problems of cultivated pea in Europe. Development of resistant cultivars is very important to environmental protection and would solve this problem to a great extent. Therefore, the resistance of five spring pea cultivars was studied to B. pisorum: Glyans, Modus; Kamerton and Svit and Pleven 4 based on the weevil damage and chemical composition of seeds. The seeds were classified as three types: healthy seeds (type one), damaged seeds with parasitoid emergence holes (type two) and damaged seeds with bruchid emergence holes (type three). From visibly damaged pea seeds by pea weevil B. pisorum was isolated the parasitoid Triaspis thoracica Curtis (Hymenoptera, Braconidae). Modus, followed by Glyans was outlined as resistant cultivars against the pea weevil. They had the lowest total damaged seed degree, loss in weight of damaged seeds (type two and type three) and values of susceptibility coefficients. A strong negative relationship (r = -0.838) between the weight of type one seeds and the proportion of type three seeds was found. Cultivars with lower protein and phosphorus (P) content had a lower level of damage. The crude protein, crude fiber and P content in damaged seeds significantly or no significantly were increased as compared with the healthy seeds due to weevil damage. The P content had the highest significant influence on pea weevil infestation. Use of chemical markers for resistance to the creation of new pea cultivars can be effective method for defense and control against B. pisorum.

  19. A Model for Sclerotinia sclerotiorum Infection and Disease Development in Lettuce, Based on the Effects of Temperature, Relative Humidity and Ascospore Density

    Science.gov (United States)

    Clarkson, John P.; Fawcett, Laura; Anthony, Steven G.; Young, Caroline

    2014-01-01

    The plant pathogen Sclerotinia sclerotiorum can cause serious losses on lettuce crops worldwide and as for most other susceptible crops, control relies on the application of fungicides, which target airborne ascospores. However, the efficacy of this approach depends on accurate timing of these sprays, which could be improved by an understanding of the environmental conditions that are conducive to infection. A mathematical model for S. sclerotiorum infection and disease development on lettuce is presented here for the first time, based on quantifying the effects of temperature, relative humidity (RH) and ascospore density in multiple controlled environment experiments. It was observed that disease can develop on lettuce plants inoculated with dry ascospores in the absence of apparent leaf wetness (required for spore germination). To explain this, the model conceptualises an infection court area containing microsites (in leaf axils and close to the stem base) where conditions are conducive to infection, the size of which is modified by ambient RH. The model indicated that minimum, maximum and optimum temperatures for ascospore germination were 0.0, 29.9 and 21.7°C respectively and that maximum rates of disease development occurred at spore densities >87 spores cm−2. Disease development was much more rapid at 80–100% RH at 20°C, compared to 50–70% RH and resulted in a greater proportion of lettuce plants infected. Disease development was also more rapid at 15–27°C compared to 5–10°C (85% RH). The model was validated by a further series of independent controlled environment experiments where both RH and temperature were varied and generally simulated the pattern of disease development well. The implications of the results in terms of Sclerotinia disease forecasting are discussed. PMID:24736409

  20. THE FARMING AND MARKETING OF ORGANIC LETTUCE: STUDY AT BOBOSAN VILLAGE, KEDUNGBANTENG SUB-DISTRICT, BANYUMAS

    Directory of Open Access Journals (Sweden)

    Irene Kartika Eka Wijayanti

    2017-09-01

    Full Text Available Banyumas has great potential as a producer of organic lettuce in term of condition of natural, human resources and availability of market. The centre producer of organic lettuce is located in district of Kedungbanteng, and managed by farmers group "abdi tani". The aim of this study is to analyze: 1. The cost and income farming of organic lettuce; 2. Financial feasibility of organic lettuce farm; 3. The channel and structure of organic lettuce market. Processing and data analysis performed qualitatively and quantitatively. The data used is to the production and marketing of organic lettuce in period of June-July 2016. Quantitative analysis performed using analysis of cost, farm income, and R/C. Qualitative analysis was conducted to determine the channel and structure of organic lettuce market. The results showed that organic lettuce farm income generating positive value and the value of R/C is greater than one (R/C >1, the farming is profitable and feasible. Organic lettuce marketing channels through the use of one channel, such farmers, traders, retailers (supermarket. Farmers faced monopsony market structure, while traders and retailers deal with oligopoly one

  1. Estudo comparativo de cultivares de trigo em latossolo roxo no estado de São Paulo em 1974 A comparative study on wheat cultivars on latossolic B "Terra Roxa" soils in the state of São Paulo in 1974

    Directory of Open Access Journals (Sweden)

    João Carlos Felício

    1976-01-01

    Full Text Available Este trabalho foi executado com o propósito de estudar o comportamento de diferentes cultivares de trigo, em latossolo roxo na região tritícola do Vale do Paranapanema no Estado de São Paulo. Foram instalados três experimentos em 1974. Os cultivares IRN-526-63, IAS-55, Sonora-63, BH-1146, IAS-54, Londrina, LA-1434 e Pitic-62 foram os que apresentaram maior produtividade por unidade de área; os cultivares IAC-5, Sonora-63, Sonora-64 x Selkirk, Triticum agropyrum, Tobari-66, IAC-11, Sonora-64, Norteno-67 e Super X mostraram-se resistentes às raças prevalentes de ferrugem do colmo. Os cultivares Super X, Sonora-64 x Selkirk, IRN-152-63 e Triticum agropyrum mostraram-se resistentes à ferrugem da folha, e BH-1146, IAC-5, IAC-11, LA-1434, T. agropyrum e IRN-152-63 foram suscetíveis ao acamamento.Selected germplasms of wheat were tested for yield potential and resistance to rusts and cultivar trials in the State of São Paulo. Performance was evaluated in several locations in 1974 in the wheat area of the State on Latossolic B "Terra Roxa" soils. The cultivars IRN-526-63, IAS-55, Sonora-63, BH-1146, IAS-54, Londrina, LA-1434 and Pitic-62 showed superior performance for yield. The cultivars IAC-5, Sonora-63, Sonora-64 x Selkink, Triticum agropyrum, Tobai-66, IAC-11, Sonora-64, Norteno-67, and Super X showed better resistance to stem rust. The cultivars Super X, Sonora-64 x Selkink, IRN-152,63, and Triticum agropyrum, were more resistant to leaf rust. The cultivars BH-1146, IAC-5, Triticum agropyrum, IRN-152-62, LA-1434 and IAC-11 were susceptible to lay.

  2. Testes de vigor em sementes de alface Seed vigor tests for lettuce seeds

    Directory of Open Access Journals (Sweden)

    Ana Lúcia P Kikuti

    2012-03-01

    Full Text Available O vigor da semente tem sido avaliado por meio de testes fisiológicos, bioquímicos e de tolerância a estresse. Mais recentemente, com o uso da análise computadorizada de imagens de plântulas, podem ser obtidas informações objetivas, em período relativamente curto, com menor interferência humana. O objetivo nesta pesquisa foi identificar testes eficientes para avaliação do vigor de sementes de alface, com ênfase para a análise de imagens digitais de plântulas. Sementes de 12 lotes (seis da cultivar Vanda e seis da Vera foram avaliadas por meio de testes de germinação, germinação a baixa temperatura (15ºC, emergência de plântulas e envelhecimento acelerado tradicional e com solução salina (NaCl 40% saturada, a 41ºC/48 h e 41ºC/72 h. Utilizou-se, também, o sistema de análise computadorizada de imagens de plântulas (SVIS®, desenvolvido pela Ohio State University (EUA, que forneceu dados referentes ao índice de vigor, uniformidade e crescimento de plântulas. Os testes foram realizados a cada três meses, durante 12 meses de armazenamento, sob condições ambiente. Com base nos resultados obtidos, concluiu-se que os testes de envelhecimento acelerado com uso de solução saturada de NaCl, a 41ºC por 48 e 72 horas e de velocidade de germinação, e os parâmetros obtidos com o software SVIS, índice de crescimento de plântulas e comprimento da raiz primária, são eficientes na avaliação do vigor de lotes de sementes de alface.The seed vigor is evaluated by traditional tests and more recently by seedling imaging analysis to obtain objective information within a short period of time. The objective of the study was to verify the accuracy of accepted vigor tests in comparison to an automated computer imaging system for seedling evaluation (SVIS® in order to assess lettuce seed vigor. Six seed lots each of two cultivars (Vanda and Vera were evaluated in the germination, cold germination (15ºC, seedling emergence and

  3. Agricultural recycling of biodigested vinasse for lettuce production

    Directory of Open Access Journals (Sweden)

    Camila Roberta Javorski Ueno

    2014-10-01

    Full Text Available The agricultural use of waste products represents an interesting alternative for nutrient cycling. Biodigested vinasse, the final waste product of vinasse biodigestion and biogas production, can be reused for agricultural purposes. The present work sought to quantify the shoot dry mass production of lettuce plants, as well as foliar nitrogen, phosphorus and potassium content following the application of biodigested vinasse on soil. Biodigested vinasse was produced from anaerobic vinasse digestion, using anaerobic sludge as a source of microorganisms. The treatments, with four replications in entirely randomized design, consisted of anaerobic sludge from a gelatin factory, vinasse in natura, biodigested vinasse and a control treatment. The experiment was conducted over 45 days using 5 L vases and applying a dose equivalent to 150 m3 ha-1 . Lettuce treated with biodigested vinasse showed higher shoot dry mass production and higher accumulation of nitrogen, phosphorus and potassium in its leaves than that treated with vinasse in natura.

  4. Fate of [14C]-zineb on lettuce plants

    International Nuclear Information System (INIS)

    Vonk, J.W.

    1976-01-01

    [1,2- 14 C]-zinc ethylenebisdithiocarbamate (zineb) was prepared and applied in droplets to leaves of lettuce plants. In aqueous suspension zineb decomposes mainly into ethylenethiourea (ETU) and 5,6-dihydro-3H-imidazo[2,1-C]-1,2,4-dithiazole-3-thione (DIDT). Lettuce plants were harvested 0,1,3,7,14 and 21 days after treatment and analysed. A high proportion of radioactivity remained on the surface of the plant and could be washed off. The following identified products were present: unchanged zineb, ETU, DIDT, 2-imidazoline and ethyleneurea. The ETU residue disappeared within 7 days, while 2-imidazoline and ethyleneurea were formed gradually. Radioactivity inside the plant consisted mostly of ethyleneurea: no ETU was present. (author)

  5. Pochonia chlamydosporia promotes the growth of tomato and lettuce plants

    Directory of Open Access Journals (Sweden)

    Rosangela Dallemole-Giaretta

    2015-10-01

    Full Text Available The fungus Pochonia chlamydosporia is one of the most studied biological agents used to control plant-parasitic nematodes. This study found that the isolates Pc-3, Pc-10 and Pc-19 of this fungus promote the growth of tomato and lettuce seedlings. The isolate Pc-19 colonized the rhizoplane of tomato seedlings in only 15 days and produced a large quantity of chlamydospores. This isolate was able to use cellulose as a carbon source, in addition to glucose and sucrose. Scanning electron microscopy (SEM revealed that hyphae of the P. chlamydosporia isolate Pc-10 penetrated the epidermal cells of the tomato roots. These three P. chlamydosporia isolates promote the growth of tomato and lettuce.

  6. Nematóide de galha em rabanete: suscetibilidade de cultivares e patogenicidade Root-knot nematode: cultivars reaction and damage to radish

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Rossi

    2004-03-01

    Hatsuka'. Radish plants were inoculated with 2,000 eggs, and the [root-gall (IG and egg-mass (IMO indexes and reproduction factor (FR] were determined 53 days after inoculation. In the other experiment, three populational levels (0, 500 (low level and 10,000 (high level nematode eggs were individually inoculated in 'Redondo Vermelho' radish cultivar. The results showed values of IG and IMO superior or equal to 2.5 and FR superior to 8.0 and, according tp these data, all tested cultivars were classified as susceptible. Meloidogyne javanica caused plant growth supression as measured by the values of fresh and dry weight of roots and the foliage of the plants, 39 days after inoculations. The average treatments containing low and high populational levels were satisfically different among themselves, thus proving its patogenic action on the cultivars evaluated.

  7. Effect of pressure on the vacuum cooling of iceberg lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, Hande Mutlu [Pamukkale University, Food Engineering Department, Faculty of Engineering, Denizli (Turkey); Ozturk, Harun Kemal [Pamukkale University, Mechanical Engineering Department, Faculty of Engineering, 20070 Kinikli, Denizli (Turkey)

    2009-05-15

    Vacuum cooling is known as a rapid evaporative cooling technique for any porous product which has free water. The aim of this paper is to apply vacuum cooling technique to the cooling of the iceberg lettuce and show the pressure effect on the cooling time and temperature decrease. The results of vacuum cooling are also compared with conventional cooling (cooling in refrigerator) for different temperatures. Vacuum cooling of iceberg lettuce at 0.7 kPa is about 13 times faster than conventional cooling of iceberg lettuce at 6 C. It has been also found that it is not possible to decrease the iceberg lettuce temperature below 10 C if vacuum cooling method is used and vacuum pressure is set to 1.5 kPa. (author) [French] Le refroidissement sous vide est connu comme une technique evaporative rapide refroidissant pour n'importe quel produit poreux qui a de l'eau libre. Le but de ce papier est d'appliquer le refroidissement sous vide pour le refroidissement de la laitue et examiner l'effet de la pression sur le temps de refroidissement et la diminution de temperature. Les resultats de refroidissement sous vide sont aussi compares avec le refroidissement conventionnel (refroidissement dans le refrigerateur) pour les differentes temperatures. Le refroidissement a vide de laitue a 0.7 kPa est environ 13 fois plus vite que le refroidissement conventionnel de laitue croquante a 6 C. Il a ete aussi constate qu'il n'est pas possible de diminuer la temperature de laitue ci-dessous 10 C si le refroidissement sous vide est utilise comme methode et la pression a vide est montree a 1.5 kPa. (orig.)

  8. Colonization of lettuce rhizosphere and roots by tagged Streptomyces

    OpenAIRE

    Maria eBonaldi; Xiaoyulong eChen; Andrea eKunova; Cristina ePizzatti; Marco eSaracchi; Paolo eCortesi

    2015-01-01

    Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plas...

  9. Cultivo da alface em túneis baixos de agrotêxtil Lettuce cultivation in low tunnels of agricultural textile

    Directory of Open Access Journals (Sweden)

    Aurélio P. Barros Júnior

    2004-12-01

    Full Text Available O experimento foi conduzido na horta da ESAM, de março a abril de 2004, com o objetivo de avaliar o desempenho de cultivares da alface em túneis baixos de agrotêxtil. O delineamento experimental utilizado foi de blocos casualizados completos em esquema fatorial 2 x 3, com quatro repetições. Os tratamentos foram constituídos pela combinação de duas cultivares de alface (Tainá e Babá de Verão e três tipos de cobertura (dois túneis baixos de 50 cm de altura de agrotêxtil branco com gramatura de 13 g/m² e 40 g/m² e sem cobertura. Avaliou-se a altura e diâmetro de plantas, número de folhas por planta, massa seca da parte aérea e produtividade. A cultivar Babá de Verão apresentou melhor desempenho em altura de plantas, número de folhas e produtividade. O túnel baixo de agrotêxtil branco com gramatura de 40 g/m² promoveu maior altura, diâmetro e produtividade de alface.The yield of lettuce cultivated under low tunnels of agricultural textile was evaluated in Mossoró, Rio Grande do Norte State, Brazil. The experiment was carried out from March to April of 2004, in a randomized complete blocks design with three treatments and four replications. The treatments were: low tunnel (with 50 cm of height of white agricultural textile with basic weight of 40 g/m²; low tunnel (with 50 cm of height of white agricultural textile with basic weight of 13 g/m² and control (treatment with no coverage. Evaluations of plant height and diameter, number of leaves per plant, shoot dry matter and yield were done. Cultivar Babá de Verão presented greater plant height, number of leaves per plant and yield. The low tunnel of agricultural textile with basic weight of 40 g/m² presented superior results of plant height, diameter and yield.

  10. Cultivar de soja BRS 66

    Directory of Open Access Journals (Sweden)

    Bertagnolli Paulo Fernando

    2002-01-01

    Full Text Available BRS 66, oriunda do cruzamento BR 83-147 x FT-Abyara, é indicada para cultivo no Rio Grande do Sul. Na média de 21 ambientes no RS, no período de 1993/94 a 1995/96, essa cultivar apresentou rendimento médio de grãos de 2.883 kg/ha. Apresenta resistência ao cancro-da-haste, à podridão-parda-da-haste, à mancha-olho-de-rã, à raça 1 de Phytophthora sojae, à pústula-bacteriana e ao oídio. Tem flor branca, pubescência marrom, tegumento da semente amarelo-fosco, hilo marrom e tipo de crescimento determinado. É de ciclo médio e apresenta estatura da planta de média a alta, com boa resistência ao acamamento.

  11. Colonization of lettuce rhizosphere and roots by tagged Streptomyces

    Directory of Open Access Journals (Sweden)

    Maria eBonaldi

    2015-02-01

    Full Text Available Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

  12. Physiological and health quality of commercial lettuce and cabbage seed

    Directory of Open Access Journals (Sweden)

    Cleyton Teles Contreiras Paiva

    2016-08-01

    Full Text Available Physiological and sanitary seed quality is essential for rapid and uniform crop establishment at field, a factor which contributes to vegetable crop production success. The aim was to evaluate physiological and sanitary quality of lettuce and cabbage seeds coming three lots acquired in trade. Physiological quality was determined by means of germination test and index of speed germination. Health status was assessed through sanity test in Petri dishes containing BDA medium. The experimental design was completely randomized with four replications and the averages of each lot compared among themselves by Tukey test (5%. No statistical analyzes were performed to health test and samples were evaluated for presence of microorganisms on the plates. Aspergillus spp., Rhizopus spp., cocci and bacillus are associated with lettuce seeds, and Aspergillus spp., cocci and bacillus are associated with cabbage seeds, but this association can not interfere with germination performance at laboratory. Information about germination contained in the package do not always coincide with those examined in situ. Lettuce and cabbage seeds are being marketed carrying pathogens.

  13. Research on lettuce growth technology onboard Chinese Tiangong II Spacelab

    Science.gov (United States)

    Shen, Yunze; Guo, Shuangsheng; Zhao, Pisheng; Wang, Longji; Wang, Xiaoxia; Li, Jian; Bian, Qiang

    2018-03-01

    Lettuce was grown in a space vegetable cultivation facility onboard the Tiangong Ⅱ Spacelab during October 18 to November 15, 2016, in order to testify the key cultivating technology in CELSS under spaceflight microgravity condition. Potable water was used for irrigation of rooting substrate and the SRF (slowly released fertilizer) offered mineral nutrition for plant growth. Water content and electric conductivity in rooting substrate were measured based on FDR(frequency domain reflectometry) principle applied first in spaceflight. Lettuce germinated with comparative growth vigor as the ground control, showing that the plants appeared to be not stressed by the spaceflight environment. Under microgravity, lettuce grew taller and showed deeper green color than the ground control. In addition, the phototropism of the on-orbit plants was more remarkable. The nearly 30-d spaceflight test verified the seed fixation technology and water& nutrition management technology, which manifests the feasibility of FDR being used for measuring moisture content and electric conductivity in rooting zone under microgravity. Furthermore, the edibility of the space-grown vegetable was proved, providing theoretical support for astronaut to consume the space vegetable in future manned spaceflight.

  14. Purification, characterization and immunomodulatory activity of polysaccharides from stem lettuce.

    Science.gov (United States)

    Nie, Chenzhipeng; Zhu, Peilei; Ma, Shuping; Wang, Mingchun; Hu, Youdong

    2018-05-15

    Stem lettuce has a long history of cultivation in China and possesses high nutritional and medicinal value. In our previous studies, extraction optimization, characterization, and bioactivities of stem lettuce polysaccharides (SLP) were investigated. In this study, SLP were further separated into two purified polysaccharides, SLP-1 and SLP-2, by anion exchange chromatography followed by size exclusion chromatography. SLP-1, with a molecular weight of 90 KDa, was mainly composed of galacturonic acid, galactose and arabinose in a molar ratio of 17.6:41.7:33.9. SLP-2, with a molecular weight of 44 KDa, was mainly composed of mannose, galacturonic acid, galactose and arabinose in a molar ratio of 11.5:69.5:9.3:8.2. In addition, both purified polysaccharides contain sulphate radicals, have triple helical structures and can promote macrophage proliferation without cytotoxicity. SLP-2 was better able to stimulate phagocytic and nitric oxide production than SLP-1. The results suggest that polysaccharides from stem lettuce could be explored as immunomodulatory agents in the field of pharmaceuticals and functional foods. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Jatropha press cake as organic fertilizer in lettuce cultivation

    Directory of Open Access Journals (Sweden)

    José R. Mantovani

    Full Text Available ABSTRACT In biodiesel production, vegetable press cake is obtained as waste, and a suitable destination for jatropha press cake would be the use in agriculture as organic fertilizer. This study aimed to evaluate the effect of jatropha press cake on soil fertility attributes and on lettuce production and accumulation of nutrients in the shoots. The experiment was conducted in pots in a greenhouse, in a randomized block design with eight treatments and five replicates. The treatments consisted of doses of jatropha press cake equivalent to 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 t ha-1. Portions of 5.5 dm3 of soil received limestone, phosphate fertilizer and the doses of jatropha press cake, and remained incubated for 30 days. After incubation, soil samples were collected, each pot received one lettuce seedling and the experiment was carried out for 45 days. The organic fertilization with jatropha press cake increased the contents of nutrients in the soil, especially K+, but caused increment in soil acidity and electrical conductivity. The use of jatropha press cake as organic fertilizer decreased lettuce production and accumulation of nutrients in the shoots.

  16. Possible Internalization of an Enterovirus in Hydroponically Grown Lettuce.

    Science.gov (United States)

    Carducci, Annalaura; Caponi, Elisa; Ciurli, Adriana; Verani, Marco

    2015-07-17

    Several studies have shown that enteric viruses can be transferred onto the surface of vegetables and fruits through spray irrigation, but, recently, reports have suggested viral contamination of vegetables sub-irrigated with reused wastewater. Hydroponic cultures, used to grow ready to eat fresh lettuce, have also been used to study the possibility of viral absorption through roots. This study was conducted to assess a possible risk of viral contamination in lettuce from contaminated water. The leaves of lettuce plants grown in hydroponic cultures where the roots were exposed to water containing Coxsakievirus B2, were analysed for evidence of the virus. The plants and water were sampled at different times and virus was measured using quantitative RT-PCR and infectivity assay. In leaf samples, the lowest observed infective data were lower than the qRT-PCR detection limits, suggesting that free viral RNA or damaged viruses are eliminated rapidly while infectious particles remain stable for a longer time. The obtained data revealed that the leaves were contaminated at a water concentration of 4.11 ± 1 Log Most Probable Number/L (8.03 ± 1 Log GC/L) a concentration observed in contaminated untreated water of wastewater treatment plants. However, the absorption dynamics and whether the virus is inactive in the leaves still remains to be clarified. Nevertheless, this work has practical implications for risk management in using reclaimed water for agricultural use; when irrigated vegetables are destined for raw consumption, virological contamination in water sources should be evaluated.

  17. Colonization of lettuce rhizosphere and roots by tagged Streptomyces.

    Science.gov (United States)

    Bonaldi, Maria; Chen, Xiaoyulong; Kunova, Andrea; Pizzatti, Cristina; Saracchi, Marco; Cortesi, Paolo

    2015-01-01

    Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots, and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

  18. Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

    Science.gov (United States)

    Esseili, Malak A.; Zhang, Zhenwen

    2012-01-01

    Noroviruses are the leading cause of food-borne outbreaks, including those that involve lettuce. The culturable porcine sapovirus (SaV) was used as a norovirus surrogate to study the persistence and the potential transfer of the virus from roots to leaves and from outer to inner leaves of lettuce plants. Treatment of lettuce with SaV was done through the roots of young plants, the soil, or the outer leaves of mature plants. Sampling of roots, xylem sap, and inner and outer leaves followed by RNA extraction and SaV-specific real-time reverse transcription (RT)-PCR was performed at 2 h and on postinoculation days (PID) 2, 5, 7, 14, and/or 28. When SaV was inoculated through the roots, viral RNA persisted on the roots and in the leaves until PID 28. When the virus was inoculated through the soil, viral RNA was detected on the roots and in the xylem sap until PID 14; viral RNA was detected in the leaves only until PID 2. No infectious virus was detected inside the leaves for either treatment. When SaV was inoculated through the outer leaves, viral RNA persisted on the leaves until PID 14; however, the virus did not transfer to inner leaves. Infectious viral particles on leaves were detected only at 2 h postinoculation. The milky sap (latex) of leaves, but not the roots' xylem sap, significantly decreased virus infectivity when tested in vitro. Collectively, our results showed the transfer of SaV from roots to leaves through the xylem system and the capacity of the sap of lettuce leaves to decrease virus infectivity in leaves. PMID:22752176

  19. Mango resistance to fruit flies. II - resistance of the alfa cultivar

    Energy Technology Data Exchange (ETDEWEB)

    Rossetto, C.J.; Bortoletto, N., E-mail: rossetto@iac.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Votuporanga, SP (Brazil). Polo Regional do Noroeste Paulista; Walder, J.M.M.; Mastrangelo, T. de A., E-mail: jmwalder@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Carvalho, C.R.L.; Castro, J.V. de, E-mail: climonta@iac.sp.gov.b, E-mail: josalba@iac.sp.gov.b [Instituto Agronomico de Campinas, SP (Brazil); Pinto, A.C. de Q. [EMBRAPA, Brasilia, DF (Brazil); Cortelazzo, A.L., E-mail: angelo@unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Biologia

    2006-07-01

    The percentage of infested mango fruits of five selected mango varieties was evaluated during three years under field conditions. Three varieties with field resistance to fruit flies had less then 10% of fruits infested. Tommy Atkins, the susceptible commercial check, had 42,9% and the susceptible check had 98.9 % of infested fruits. The three field resistant varieties plus the susceptible commercial check, Tommy Atkins, were further tested in laboratory, under caged conditions, with artificial infestation of Anastrepha obliqua. The attempts of oviposition and the number of pupae developed from each fruit were evaluated. Under caged conditions, the cultivar Alfa maintained its field resistance and Espada Stahl and IAC 111 lost the field resistance and were as susceptible as Tommy Atkins. The attempts of oviposition were positively and highly correlated with the number of pupae developed in the fruits. Non preference for oviposition was confirmed as the main mechanism of resistance of mango fruits to fruit flies. In the absence of a more susceptible variety (no choice test) the cultivar Alfa has kept the resistance (author)

  20. Mango resistance to fruit flies. II - resistance of the alfa cultivar

    International Nuclear Information System (INIS)

    Rossetto, C.J.; Bortoletto, N.; Carvalho, C.R.L.; Castro, J.V. de; Pinto, A.C. de Q.; Cortelazzo, A.L.

    2006-01-01

    The percentage of infested mango fruits of five selected mango varieties was evaluated during three years under field conditions. Three varieties with field resistance to fruit flies had less then 10% of fruits infested. Tommy Atkins, the susceptible commercial check, had 42,9% and the susceptible check had 98.9 % of infested fruits. The three field resistant varieties plus the susceptible commercial check, Tommy Atkins, were further tested in laboratory, under caged conditions, with artificial infestation of Anastrepha obliqua. The attempts of oviposition and the number of pupae developed from each fruit were evaluated. Under caged conditions, the cultivar Alfa maintained its field resistance and Espada Stahl and IAC 111 lost the field resistance and were as susceptible as Tommy Atkins. The attempts of oviposition were positively and highly correlated with the number of pupae developed in the fruits. Non preference for oviposition was confirmed as the main mechanism of resistance of mango fruits to fruit flies. In the absence of a more susceptible variety (no choice test) the cultivar Alfa has kept the resistance (author)

  1. Zooming in on the lettuce genome: species relationships in Lactuca s.l., inferred from chromosomal and molecular characters

    OpenAIRE

    Koopman, W.J.M.

    2002-01-01

    Lactuca sativa (cultivated lettuce) is the world's most important leafy salad vegetable. Apart from L. sativa , the genus Lactuca contains ca. 75 wild species, potentially useful to improve, for example, taste, texture, and disease resistance of cultivated lettuce. The wild species L. serriola (Prickly Lettuce), L. saligna (Least Lettuce), and L. virosa (Great...

  2. Suficiência amostral para alface cultivada em diferentes ambientes Sample sufficiency for lettuce grown in different environments

    Directory of Open Access Journals (Sweden)

    Daniel Santos

    2010-04-01

    Full Text Available Com o objetivo de estimar o tamanho de amostra para alface cultivada em diferentes ambientes, foram conduzidos quatro cultivos com alface, dois deles foram realizados no ano de 2007, com a cultivar 'Vera', e dois foram realizados no ano de 2008, com a cultivar 'Amanda'. Os ambientes em 2007 foram estufa e a campo, e em 2008 foram estufa e túnel. Em ambos os anos de cultivo, foram avaliadas a fitomassa fresca e fitomassa seca. Para cada variável, em cada linha de cultivo, foram estimadas a média, a variância e o coeficiente de variação. Para testar a homogeneidade das variâncias entre as linhas, aplicou-se o teste de Bartlett, a 5% de significância. Nos casos em que as variâncias das linhas foram homogêneas, calculou-se um CV% médio para cada ambiente e este foi utilizado para o cálculo do tamanho de amostra. Nos casos em que as variâncias foram heterogêneas, utilizou-se o maior CV% do ambiente para o cálculo do tamanho da amostra. Os resultados mostraram que, em 40% dos experimentos, quando a variável foi a fitomassa fresca, e em 60%, quando foi a seca, os diferentes ambientes de produção proporcionaram variabilidades significativamente diferentes entre as linhas de cultivo. Foi possível determinar que, com a semiamplitude do intervalo de confiança de 10%, devem ser amostradas 30, 40 e 33 plantas na linha de cultivo, na estufa, no túnel e a campo respectivamente, para a fitomassa fresca das plantas. Já para a fitomassa seca das plantas devem ser amostradas 27, 29 e 32 plantas, respectivamente, para estufa, túnel e campo.The aim of this study was to estimate the sample size for lettuce cultivated in different environments, and for this four lettuce crops were cultivated. Two of them were conducted in 2007, with the cultivar Vera and two in 2008 with the cultivar 'Amanda'. The environments in 2007 were greenhouse and field and in 2008, greenhouse and tunnel. In both years of cultivation the fresh biomass and dry weight were

  3. The effect of nitrogen fertilization and irradiation on barley susceptibility to net blotch disease

    International Nuclear Information System (INIS)

    Arabi, M.I.E.; Al-safadi, B.; Charbaji, T.

    2000-11-01

    Isolates of Drechslera teres f. sp. teres that cause net blotch symptoms on barley were collected from fields in different regions of Syria. there virulence spectra were determined using 11 barley cultivars. Cultivars exhibited a continuos range of response from very susceptible to moderately resistant. Isolate Raqa 13 had the highest mean virulence, then Halap 2, whereas ICARDA 3 was the lowest virulent. The effect of three concentrations (1000, 1500, 2000 ppm) of nitrogen (Urea 45%) fertilizer, and two doses of gamma ray (10 and 20 Gy), on susceptibility to infection by Drechslera teres were studied. Two barley cultivars (Thibaut and Furia) were used in this study. Results showed that 1000 ppm (N) and 15 Gy dose treatment had a positive effect on decreasing the susceptibility. (author)

  4. Adaptation of cotton cultivars | Wondimu | African Crop Science ...

    African Journals Online (AJOL)

    For each cultivar a linear regression of yield on the mean yield of all cultivars for each year was computed to measure cultivar adaptation. The cultivars with the highest mean yield exhibited a similar degree of adaptation to different environments with regression coefficient close to 1.0. For example, the breeding lines, Acala ...

  5. 76 FR 81468 - Notice of Decision to Authorize the Importation of Shredded Lettuce From Egypt Into the...

    Science.gov (United States)

    2011-12-28

    ...] Notice of Decision to Authorize the Importation of Shredded Lettuce From Egypt Into the Continental... fresh shredded lettuce from Egypt. Based on the findings of a pest risk analysis, which we made... introducing or disseminating plant pests or noxious weeds via the importation of fresh shredded lettuce from...

  6. 76 FR 50992 - Notice of Availability of a Pest Risk Analysis for the Importation of Shredded Lettuce From Egypt

    Science.gov (United States)

    2011-08-17

    ...] Notice of Availability of a Pest Risk Analysis for the Importation of Shredded Lettuce From Egypt AGENCY... into the continental United States of fresh shredded lettuce from Egypt. Based on this analysis, we... fresh shredded lettuce from Egypt. We are making the pest risk analysis available to the public for...

  7. Optimal control of nitrate in lettuce by a hybrid approach: differential evolution and adjustable control weight gradient algorithms

    NARCIS (Netherlands)

    Lopez Cruz, I.L.; Willigenburg, van L.G.; Straten, van G.

    2003-01-01

    Abstract Since high concentration levels of nitrate in lettuce and other leafy vegetables are undesirable, cultivation of lettuce according to specified governmental regulations is currently an important issue. Therefore, methods are sought in order to produce a lettuce crop that allow maximization

  8. The Effect of Plant Cultivar, Growth Media, Harvest Method and Post Harvest Treatment on the Microbiology of Edible Crops

    Science.gov (United States)

    Hummerick, Mary P.; Gates, Justin R.; Nguyen, Bao-Thang; Massa, Gioia D.; Wheeler, Raymond M.

    2011-01-01

    Systems for the growth of crops in closed environments are being developed and tested for potential use in space applications to provide a source of fresh food. Plant growth conditions, growth media composition and harvest methods can have an effect on the microbial population of the plant, and therefore should be considered along with the optimization of plant growth and harvest yields to ensure a safe and palatable food crop. This work examines the effect of plant cultivar, growth media, and harvest method on plant microbial populations. Twelve varieties of leafy greens and herbs were grown on a mixture of Fafard #2 and Arcillite in the pillow root containment system currently being considered for the VEGGIE plant growth unit developed by Orbitec. In addition, ,Sierra and Outredgeous lettuce varieties were grown in three different mixtures (Fafard #2, Ardllite, and Perlite/Vermiculite). The plants were analyzed for microbial density. Two harvest methods, "cut and come again" (CACA) and terminal harvest were also compared. In one set ofexpe'riments red leaf lettuce and mizuna were grown in pots in a Biomass Production System for education. Plants were harvested every two weeks by either method. Another set of experiments was performed using the rooting pillows to grow 5 varieties of leafy greens and cut harvesting at different intervals. Radishes were harvested and replanted at two-week intervals. Results indicate up to a 3 IOglO difference in microbial counts between some varieties of plants. Rooting medium resulted in an approximately 2 IOglO lower count in the lettuce grown in arscillite then those grown in the other mixtures. Harvest method and frequency had less impact on microbial counts only showing a significant increase in one variety of plant. Post harvest methods to decrease the bacterial counts on edible crops were investigated in these and other experiments. The effectiveness of PRO-SAN and UV-C radiation is compared.

  9. Physiological Responses of Some Iranian Grape Cultivars to Iron Chelate Application in Calcareous Soil

    Directory of Open Access Journals (Sweden)

    H. Doulati Baneh

    2016-07-01

    Full Text Available Introduction: Iron chlorosis is considered to be one of the most important nutritional disorders in grapevines, particularly in calcareous soils that under these conditions fruit yield and quality is depressed in the current year and fruit buds poorly develop for following year. Symptoms of iron chlorosis in orchards and vineyards are usually more frequent in spring when shoot growth is rapid and bicarbonate concentration in the soil solution buffers soil pH in the rhizosphere and root apoplast. Several native grapevine (Vitis vinifera L. genotypes, highly appreciated for their organoleptic characteristics and commercial potential, are widely cultivated in Iran. Cultivated plants differ as to their susceptibility to Fe deficiency in calcareous soils, some being poorly affected while others showing severe leaf chlorotic symptoms. Selection and the use of Fe-efficient genotypes is one of the important approaches to prevent this nutritional problem. In this research the response of three local grapevine cultivars was evaluated to iron chelate consumption in a calcareous soil (26% T.N.V. Materials and Methods: Well rooted woody cuttings of three autochthonous varieties (Rasha, Qezel uzum, Keshmeshi Qermez were cultivated in pots filled with a calcareous soil with iron chelate consumption at three rates (0, 7.5 and 15 mg Fe/ Kg soil. The study was conducted with two factors (cultivar and iron chelate and 3 replicates in a factorial arrangement based on randomized complete block design. Plant parameters including vegetative growth, chlorophyll index and leaf area were monitored during the growth period. At the end of the treatment, fresh and dry weight of shoots and roots were determined. The concentrations of macro and micro elements in the leaves were assayed using an atomic absorption and spectrophotometer. One-way-ANOVA was applied comparing the behavior of the cultivars growing. Results and Discussion: Analysis of variance showed that chlorophyll

  10. Equações de estimativa da fitomassa da parte aérea da alface Equations to estimate shoot phytomass of lettuce

    Directory of Open Access Journals (Sweden)

    Braulio Otomar Caron

    2007-10-01

    Full Text Available O objetivo deste trabalho foi identificar equações de regressão que expressem o acúmulo de fitomassa a partir de variáveis meteorológicas e índices de crescimento da cultura, com a finalidade de avaliar o crescimento da alface cultivada em estufa plástica e a campo, em diferentes épocas do ano. No estudo, foi utilizada a cultivar "Regina". As variáveis meteorológicas determinadas foram a temperatura, a umidade relativa média do ar e a radiação solar fotossinteticamente ativa acumulada. Os índices de crescimento da alface utilizados foram a fitomassa seca e o índice de área foliar. Independentemente da época do ano, os resultados evidenciaram que as equações de regressão simples, utilizando as variáveis índice de área foliar ou radiação solar fotossinteticamente ativa acumulada, apresentaram melhor desempenho na estimativa da fitomassa (R²>0,88 nos dois ambientes. As equações de regressão múltipla, apesar de englobarem mais variáveis, apresentaram pequeno acréscimo no valor do R².The aim of this paper was to propose regression equations that express the dry matter accumulation in lettuce using meteorological parameters and growth index, to modeling the lettuce growth in greenhouse and in the field, in different growth season. The "Regina" cultivar was utilized. The meteorological variables determined were air temperature and relative humidity average and accumulated photosynthetically active radiation. The growth indexes of lettuce used were dry mass and leaf area index. Independent of the growth season, the results shown that linear regressions utilizing variables leaf area index and accumulated photosynthetically active radiation provided a good estimate of the dry mass (R²>0.88 for both seasons. The multiple regressions need more data, but shown a little increase in R² value.

  11. Production system and harvesting stage influence on nitrate content and quality of butterhead lettuce

    Directory of Open Access Journals (Sweden)

    Siti Fairuz Yosoff

    2015-01-01

    Full Text Available Leafy vegetables such as lettuce grown under different production systems may accumulate different concentrations of nitrate which may reach to the levels potentially toxic to humans. Moreover, nitrate accumulation varies in various plant parts and physiological age of the plant. Therefore, to determine the effect of production system and harvesting stage on nitrate accumulation and quality of butterhead lettuce, a study was conducted considering two lettuce production systems namely hydroponic and organic, and four different harvesting stages such as 35, 38, 41 and 44 days after transplanting (DAT. The experimental design was complete randomized design (CRD with four replications. Hydroponic and organic systems performed similar in terms of yield, quality and nitrate content of butterhead lettuce. Delaying harvesting can not only increase yield but also can minimize nitrate accumulation and health hazard risk as well. Delay in harvesting stage may result in quality deterioration of lettuce and increased production cost. Thus, a compromise is necessary to consider 41 DAT as the optimum stage to harvest butterhead lettuce with significantly higher reduction of nitrate content in both outer adult leaf blades and young leaves of hydroponic lettuce. Fresh weight, firmness and color of butterhead lettuce at this stage were still acceptable.

  12. Nondestructive phenotyping of lettuce plants in early stages of development with optical sensors

    Science.gov (United States)

    Rapid development of plants is important for the production of ‘baby-leaf’ lettuce that is harvested when plants reach the four- to eight-leaf stage of growth. However, environmental factors, such as high or low temperature, or elevated concentrations of salt, inhibit lettuce growth. Therefore, nond...

  13. A detailed linkage map of lettuce based on SSAP, AFLP and NBS markers

    NARCIS (Netherlands)

    Syed, H.; Sorensen, A.P.; Antonise, R.; van de Wiel, C.; van der Linden, C.G.; van 't Westende, W.; Hooftman, D.A.P.; den Nijs, J.C.M.; Flavell, A.J.

    2006-01-01

    Abstract Molecular markers based upon a novel lettuce LTR retrotransposon and the nucleotide binding site-leucine-rich repeat (NBS-LRR) family of disease resistance-associated genes have been combined with AFLP markers to generate a 458 locus genetic linkage map for lettuce. A total of 187

  14. Fluorescence hyperspectral imaging technique for the foreign substance detection on fresh-cut lettuce

    Science.gov (United States)

    Nondestructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed in order to detect worms on fresh-cut lettuce. The optimal wavebands for detecting worms on fresh-cut lettuce were investigated using the one-way ANOVA analysis and correlation analysis. The worm detec...

  15. Accuracy, reliability, and timing of visual evaluations of decay in fresh-cut lettuce

    Science.gov (United States)

    Visual assessments are used for evaluating the quality of food products, such as fresh-cut lettuce packaged in bags with modified atmosphere. We have compared the accuracy and the reliability of visual evaluations of decay on fresh-cut lettuce performed with experienced and inexperienced raters. In ...

  16. Dissipation and Residues of Pyrethrins in Leaf Lettuce under Greenhouse and Open Field Conditions.

    Science.gov (United States)

    Pan, Lixiang; Feng, Xiaoxiao; Zhang, Hongyan

    2017-07-21

    Pyrethrins are nowadays widely used for prevention and control of insects in leaf lettuce. However, there is a concern about the pesticide residue in leaf lettuce. A reliable analytical method for determination of pyrethrins (pyrethrin-and П, cinerin І and П, and jasmolin І and П) in leaf lettuce was developed by using gas chromatography-mass spectrometry (GC-MS). Recoveries of pyrethrins in leaf lettuce at three spiking levels were 99.4-104.0% with relative standard deviations of 0.9-3.1% ( n = 5). Evaluation of dissipation and final residues of pyrethrins in leaf lettuce were determined at six different locations, including the open field, as well as under greenhouse conditions. The initial concentration of pyrethrins in greenhouse (0.57 mg/kg) was higher than in open field (0.25 mg/kg) and the half-life for pyrethrins disappearance in field lettuce (0.7 days) was less than that greenhouse lettuce (1.1 days). Factors such as rainfall, solar radiation, wind speed, and crop growth rate are likely to have caused these results. The final residue in leaf lettuce was far below the maximum residue limits (MRLs) (1 mg/kg established by the European Union (EU), Australia, Korea, Japan).

  17. Genetics of the partial resistance against race 2 of Verticillium dahliae in lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) production on the Coastal California is threatened by Verticillium wilt, a soil borne fungal disease caused by Verticillium dahliae that diminishes yield and quality. Two races of V. dahliae were identified on lettuce, race 1 and race 2. Complete resistance to race 1 is c...

  18. On-line fresh-cut lettuce quality measurement system using hyperspectral imaging

    Science.gov (United States)

    Lettuce, which is a main type of fresh-cut vegetable, has been used in various fresh-cut products. In this study, an online quality measurement system for detecting foreign substances on the fresh-cut lettuce was developed using hyperspectral reflectance imaging. The online detection system with a s...

  19. Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

    NARCIS (Netherlands)

    Zhang, N.

    2008-01-01

    Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29

  20. Incorporation of temperature and solar radiation thresholds to modify a lettuce downy mildew warning system

    NARCIS (Netherlands)

    Wu, B.M.; Bruggen, van A.H.C.; Subbarao, K.V.; Scherm, H.

    2002-01-01

    The effect of temperature on infection of lettuce by Bremia lactucae was investigated in controlled environment studies and in the field. In controlled conditions, lettuce seedlings inoculated with B. lactucae were incubated at 15, 20, 25, or 30°C during a 4-h wet period immediately after

  1. Phenotypic profiles of Armenian grape cultivars

    Directory of Open Access Journals (Sweden)

    Aroutiounian Rouben

    2015-01-01

    Full Text Available The conservation and sustainable use of grapevine biodiversity in Armenia is particularly important due to the large number of traditional local varieties. Being partially different from European grapevine gene pool, the material of Armenian local cultivars significantly contributes to the understanding of the genetic variation and is valuable source for target selection. During last years many Armenian grapevine cultivars have been already described and their genotypes determined, but some local varieties and wild accessions remain unidentified and their phenotypic characteristics overlooked. The comprehensive analysis of phenotypes is essential for research, including genetic association studies, cultivar evaluation and selection. The goal of our research was the phenotyping on the base of reproductive, carpological and analytical characteristics of 80 Armenian aboriginal and new grape cultivars. Description of phenotypic profiles is important step towards identification and conservation of genetic resources of Armenian grapes. In future, these data can be applied for breeding of improved grape varieties targeted to fresh consumption and wine production.

  2. Analysis of deoxynivalenol and deoxynivalenol-3-glucosides content in Canadian spring wheat cultivars inoculated with Fusarium graminearum.

    Science.gov (United States)

    Amarasinghe, Chami C; Simsek, Senay; Brûlé-Babel, Anita; Fernando, W G Dilantha

    2016-07-01

    Contamination of wheat grains with Fusarium mycotoxins and their modified forms is an important issue in wheat industry. The objective of this study was to analyse the deoxynivalenol (DON) and deoxynivalenol-3-glucosides (D3G) content in Canadian spring wheat cultivars grown in two locations, inoculated with a mixture of 3-acetyldeoxynivalenol (3-ADON)-producing Fusarium graminearum strains and a mixture of 15-acetlyldeoxynivalenol (15-ADON)-producing F. graminearum strains. According to the analysis of variance, significant differences were observed among the cultivars for Fusarium head blight (FHB) disease index, Fusarium-damaged kernel percentage (%FDK), DON content and D3G content. When the effect of chemotype was considered, significant differences were observed for FHB disease index, FDK percentage and DON content. The D3G content and D3G/DON ratio were not significantly different between the chemotypes, except for D3G content at the Winnipeg location. The Pearson correlation coefficient between DON and D3G was 0.84 and 0.77 at Winnipeg and Carman respectively. The highest D3G/DON ratio was observed in cultivars Carberry (44%) in Carman and CDC Kernen (63.8%) in Winnipeg. The susceptible cultivars showed lower D3G/DON ratio compared with the cultivars rated as moderately resistant and intermediate. The current study indicated that Canadian spring cultivars produce D3G upon Fusarium infection.

  3. Interactions in the Agrobacterium-soybean system and capability of some Brazilian soybean cultivars to produce somatic embryos

    Directory of Open Access Journals (Sweden)

    Mauro Antonio Orlando Di

    2000-01-01

    Full Text Available Twenty-five Brazilian soybean cultivars were studied for susceptibility to four strains of Agrobacterium tumefaciens (C58, Ach5, Bo542 and A281 and for their ability to produce somatic embryos. Twelve plants of each cultivar were inoculated in a greenhouse at 4-6 weeks of age, using 12 inoculation sites per plant. The number of galls formed on plants were counted 8-10 weeks after inoculation. To study ability to produce somatic embryos, immature cotyledons, 4-6 mm in length, were plated onto N10 medium for induction of somatic embryogenesis, using four Petri dishes with 20 cotyledons for each cultivar. The embryogenic tissues were transferred onto new N10 medium six times at 15-day intervals and the number of somatic embryos per cultivar determined. Significant interaction between soybean cultivars and A. tumefaciens strains was observed; the most virulent strain was A281. The opine type apparently had no effect on strain virulence, and the most embryogenic cultivars were IAS-5, Cristalina, FT-Cometa, IAC-7 and OC-3.

  4. Sensory Description of Cultivars (Coffea Arabica L. Resistant to Rust and Its Correlation with Caffeine, Trigonelline, and Chlorogenic Acid Compounds

    Directory of Open Access Journals (Sweden)

    Larissa de Oliveira Fassio

    2016-01-01

    Full Text Available Considering the importance of the chemical compounds in Arabica coffee beans in the definition of the drink sensory quality and authentication of coffee regions, the aim of this study was to evaluate, from principal component analysis—PCA—if there is a relation between the caffeine, trigonelline, and chlorogenic acid (5-CQA content and the sensory attributes of the drink, and in this context, enabling the differentiation of cultivars in two coffee-producing regions of Brazil. We evaluated seven rust-resistant Coffea arabica cultivars, and two rust-susceptible cultivars in two cultivation environments: Lavras, in the southern region of Minas Gerais state, and Patrocinio in the Cerrado region of Minas Gerais. The flavor and acidity were determinant for differentiation of the cultivars and their interaction with the evaluated environments. Cultivars Araponga MG1, Catigua MG2, and Catigua MG1 are the most suitable for the production of specialty coffee in the state of Minas Gerais. A poor correlation was found between caffeine, trigonelline, 5-CQA contents, and fragrance, flavor, acidity, body, and final score attributes. However, these compounds enabled the differentiation of the environments. The PCA indicated superiority in the sensory quality of cultivars resistant to rust, compared to the control, Bourbon Amarelo, and Topázio MG1190.

  5. Mutation breeding of autotetraploid Achimenes cultivars

    International Nuclear Information System (INIS)

    Broertjes, C.

    1976-01-01

    Colchicine-induced autotetraploids of three Achimenes cultivars were irradiated with X-rays or fast neutrons. The results were compared, in one cultivar, with those of the irradiated diploid form. The mutation frequency after irradiation of the autotetraploid was a 20-40 fold higher as compared to the corresponding diploid. These results may open new possibilities for mutation breeding, though they are hard to explain. Several promising mutants were selected. (author)

  6. Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting

    DEFF Research Database (Denmark)

    Keraita, Bernard; Konradsen, Flemming; Drechsel, Pay

    2007-01-01

    OBJECTIVE: To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. METHODS: Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials...... were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. RESULTS: On average, 0.65 log units for indicator thermotolerant coliforms and 0.......4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes/ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0...

  7. New cultivars of jujube induced by mutation

    International Nuclear Information System (INIS)

    Hoang, V.T.; Tuynh, N.V.

    1989-01-01

    Full text: Mutation breeding of jujube (Ziziphus mauritiana Lin.) received attention by the Food Crops Research Institute since 1978. Mutations can be directly released as new cultivars or indirectly as bud grafting source. N-methyl-N-nitroso urea (MNH) was used at a concentration of 0.02-0.04% for 12 h treatment of pre-germinated seeds of different jujube cultivars. Some useful mutants were selected and directly released as new cultivars to farmers. Of the selected mutants two cultivars, ''Ma hong'' and ''Dao tien'', are the most preferable and popularly grown in the country. ''Ma hong'' is a mutant of ''Gia Loc'', a very popular cultivar. Main useful traits of ''Gia Loc'' such as early maturing, two crops of fruits per year are maintained (harvest in December and August). ''Ma hong'' has round-formed, pink rose coloured, sweeter fruits and stable fruit yield in off-season (Aug.) as compared with oval-formed, yellow-coloured and sour fruit of ''Gia Loc''. ''Dao tien'' is a mutant of the local variety ''Thien Phien'' with quite different traits. The original cultivar is late maturing (harvested in Feb.) with one crop of fruit per year and has small fruits (mean wt. of fruit at harvest 20 g). ''Dao tien'' is one month earlier in maturing allowing two crops of fruit per year (harvested in Jan. and Nov.). Fruits are round-formed, bigger (mean wt. of fruit: 25 g) and more tasteful (peach-flavored and brittle). (author)

  8. Damage evaluation of Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) on five apple cultivars under laboratory conditions

    International Nuclear Information System (INIS)

    Branco, E.S.; Vendramin, J.D.; Denardi, F.; Nora, I.

    1999-01-01

    The apple production losses in southern Brazil caused by the attack of the fruit fly Anastrepha fraterculus can reach up to 100% in some years. Its control demands intensive systematic sprays of insecticides, which increase production costs and affect environmental quality. In terms of integrated pest management, the use of resistant cultivars represents one of the most important alternatives to control this apple pest. With the objective of identifying sources of host plant resistance, apple fruits of different cultivars from the Clonal Germplasm Repository of the EPAGRI Research Station of Cacador were tested. The experiment consisted of 5 treatments (cultivars) with 5 replicates. Fruits at the harvest stage were used. The fruits were placed in boxes (40x110 cm), where they were exposed to oviposition by the fruit fly. After infestation, fruits were left on shelves at room temperature for 10 days in order to evaluate the damage level according to the following scale: 1 = fruit without attack; 2 = fruit with punctures and/or deformation without galleries; 3 = fruit with punctures and/or deformation and galleries; 4 = fruit with punctures and/or deformations, galleries and larvae. The Gala cultivar was the most susceptible, with an average damage level of 3.4, differing from the cultivars Fuji and Royal Red Delicious (damage levels of 1.6 and 1.2, respectively). The Belgolden and Sansa clones presented intermediate damage levels. A. fraterculus preferred to oviposit in the Golden Delicious group compared with the Delicious group. These studies suggest good possibilities for reduction of insecticide sprays to control the fruit fly in the cv. Fuji, as well as the incorporation of resistance factor in apple cultivars. (author)

  9. Association analysis of bacterial leaf spot resistance and SNP markers derived from expressed sequence tags (ESTs) in lettuce (Lactuca sativa L.)

    Science.gov (United States)

    Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is a devastating disease of lettuce worldwide. Since there are no chemicals available for effective control of the disease, host-plant resistance is highly desirable to protect lettuce production. A total of 179 lettuce ge...

  10. Comportamento de cultivares de trigo em dois solos do estado de São Paulo A Comparative study of wheat cultivars on two types of soil in the state of São Paulo

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Camargo

    1975-01-01

    Full Text Available Foram instalados dois ensaios de cultivares de trigo, sendo um na Estação Experimental de Tietê, e o outro, na Fazenda Santa Isabel, município de Itaberá. Os cultivares IRN-526-63, Pitic-62 e IRN-152-63, de origem mexicana, não se adaptaram às condições adversas do sul do Estado (Itaberá, entre as quais destacaram-se: baixa saturação em bases, baixíssimo teor de fósforo e principalmente a influência do Al3+ trocável ocasionando "crestamento" nas plantas. Os cultivares IAC-10, IAC-7, BH-1146, IAC-9, S-33, IAC-11 e IAC-8 apresentaram tolerância a essa condição adversa. No ensaio de Tietê, onde o solo mostrou altos teores de K+ e PO4³ , bom teor de Ca2+ 4- Mg2+ , não apresentando alumínio livre, os cultivares IRN-526-63 e Pitic-62 desenvolveram-se normalmente, apresentando produções superiores às dos demais cultivares estudados.This paper presents the results of two cultivar trials on wheat (Triticum aestivum L., carried out at the Tietê Experiment Station and at Santa Isabel Farm, Itaberá. The cultivars IRN-526-63, IRN-152-63 e Pitic-62, Mexican germoplasms, were very susceptible to "crestamento" at Itaberá soil, giving small yields. The Brazilian germoplasms showed tolerance to Al3+ , with average yields. At Tietê trial, IRN-526 and Pitic-62 cultivars showed good performance, having the most yield in this condition.

  11. Microbial Profile of Soil-Free versus In-Soil Grown Lettuce and Intervention Methodologies to Combat Pathogen Surrogates and Spoilage Microorganisms on Lettuce

    Directory of Open Access Journals (Sweden)

    Sujata A. Sirsat

    2013-11-01

    Full Text Available Aquaponics is an effective method to practice sustainable agriculture and is gaining popularity in the US; however, the microbial safety of aquaponically grown produce needs to be ascertained. Aquaponics is a unique marriage of fish production and soil-free produce (e.g., leafy greens production. Fish are raised in fresh water tanks that are connected to water filled beds where fruits and vegetables are grown. The fish bi-products create nutrient-rich water that provides the key elements for the growth of plants and vegetables. The objective of this study was to perform a comparative analysis of the microbial safety and quality of aquaponic lettuce and soil grown lettuce (conventional, bagged, certified organic, and field lettuce. Following this, an intervention study was performed to combat foodborne pathogen surrogates (Salmonella and E. coli, spoilage, and fecal microorganisms using 2.5% acetic acid. The results of the comparative analysis study showed that aquaponically grown lettuce had significantly lower concentration of spoilage and fecal microorganisms compared to in-soil grown lettuce. The intervention study showed that diluted vinegar (2.5% acetic acid significantly reduced Salmonella, E. coli, coliforms, and spoilage microorganisms on fresh lettuce by 2 to 3 log CFU/g. Irrespective of growing methods (in-soil or soilless, it is crucial to incorporate good agricultural practices to reduce microbial contamination on fresh produce. The intervention employed in this study can be proposed to small farmers and consumers to improve quality and safety of leafy greens.

  12. Microbial Profile of Soil-Free versus In-Soil Grown Lettuce and Intervention Methodologies to Combat Pathogen Surrogates and Spoilage Microorganisms on Lettuce.

    Science.gov (United States)

    Sirsat, Sujata A; Neal, Jack A

    2013-11-11

    Aquaponics is an effective method to practice sustainable agriculture and is gaining popularity in the US; however, the microbial safety of aquaponically grown produce needs to be ascertained. Aquaponics is a unique marriage of fish production and soil-free produce (e.g., leafy greens) production. Fish are raised in fresh water tanks that are connected to water filled beds where fruits and vegetables are grown. The fish bi-products create nutrient-rich water that provides the key elements for the growth of plants and vegetables. The objective of this study was to perform a comparative analysis of the microbial safety and quality of aquaponic lettuce and soil grown lettuce (conventional, bagged, certified organic, and field lettuce). Following this, an intervention study was performed to combat foodborne pathogen surrogates ( Salmonella and E. coli ), spoilage, and fecal microorganisms using 2.5% acetic acid. The results of the comparative analysis study showed that aquaponically grown lettuce had significantly lower concentration of spoilage and fecal microorganisms compared to in-soil grown lettuce. The intervention study showed that diluted vinegar (2.5% acetic acid) significantly reduced Salmonella , E. coli , coliforms, and spoilage microorganisms on fresh lettuce by 2 to 3 log CFU/g. Irrespective of growing methods (in-soil or soilless), it is crucial to incorporate good agricultural practices to reduce microbial contamination on fresh produce. The intervention employed in this study can be proposed to small farmers and consumers to improve quality and safety of leafy greens.

  13. Possible Internalization of an Enterovirus in Hydroponically Grown Lettuce

    Directory of Open Access Journals (Sweden)

    Annalaura Carducci

    2015-07-01

    Full Text Available Several studies have shown that enteric viruses can be transferred onto the surface of vegetables and fruits through spray irrigation, but, recently, reports have suggested viral contamination of vegetables sub-irrigated with reused wastewater. Hydroponic cultures, used to grow ready to eat fresh lettuce, have also been used to study the possibility of viral absorption through roots. This study was conducted to assess a possible risk of viral contamination in lettuce from contaminated water. The leaves of lettuce plants grown in hydroponic cultures where the roots were exposed to water containing Coxsakievirus B2, were analysed for evidence of the virus. The plants and water were sampled at different times and virus was measured using quantitative RT-PCR and infectivity assay. In leaf samples, the lowest observed infective data were lower than the qRT-PCR detection limits, suggesting that free viral RNA or damaged viruses are eliminated rapidly while infectious particles remain stable for a longer time. The obtained data revealed that the leaves were contaminated at a water concentration of 4.11 ± 1 Log Most Probable Number/L (8.03 ± 1 Log GC/L a concentration observed in contaminated untreated water of wastewater treatment plants. However, the absorption dynamics and whether the virus is inactive in the leaves still remains to be clarified. Nevertheless, this work has practical implications for risk management in using reclaimed water for agricultural use; when irrigated vegetables are destined for raw consumption, virological contamination in water sources should be evaluated.

  14. Reação de cultivares de abacateiro à podridão de raízes Reaction of avocado cultivars to avocado root rot

    Directory of Open Access Journals (Sweden)

    Ciro Hideki Sumida

    2009-07-01

    trees, one of each cultivar, in three different points of the root. In the each cultivar, from the four roots, one was used as check, where it was implanted health tissue. The evaluation was held at 120 day after inoculation, observing the roots externally, searching for color alterations and pathogen structures on the root surface region at the inoculated points. Internally, the bark was removed to visualize the alterations at the inoculated points observing alteration in the tissue color and measuring the darking extension (aparent lesion. On the lesion, segments of the root were taken and implanted on a medium of corn meal - agar, incubated to check the colonization in the area without darkness, that is, a-non apparent colonization. From the evaluated cultivars, 'Hass' was the least susceptible to P. cinnamomi when compared with 'Fortuna' and 'Margarida'. It was also observed that this pathogen may show development or colonization on root tissue out of the symptomatic areas.

  15. Stimulating productivity of hydroponic lettuce in controlled environments with triacontanol

    Science.gov (United States)

    Knight, S. L.; Mitchell, C. A.

    1987-01-01

    Triacontanol (1-triacontanol) applied as a foliar spray at 10(-7) M to 4-day-old, hydroponically grown leaf lettuce (Lactuca sativa L.) seedlings in a controlled environment increased leaf fresh and dry weight 13% to 20% and root fresh and dry weight 13% to 24% 6 days after application, relative to plants sprayed with water. When applied at 8 as well as 4 days after seeding, triacontanol increased plant fresh and dry weight, leaf area, and mean relative growth rate 12% to 37%. There was no benefit of repeating application of triacontanol in terms of leaf dry weight gain.

  16. Cultivar identification and genetic relationship of pineapple (Ananas comosus) cultivars using SSR markers.

    Science.gov (United States)

    Lin, Y S; Kuan, C S; Weng, I S; Tsai, C C

    2015-11-25

    The genetic relationships among 27 pineapple [Ananas comosus (L.) Merr.] cultivars and lines were examined using 16 simple sequence repeat (SSR) markers. The number of alleles per locus of the SSR markers ranged from 2 to 6 (average 3.19), for a total of 51 alleles. Similarity coefficients were calculated on the basis of 51 amplified bands. A dendrogram was created according to the 16 SSR markers by the unweighted pair-group method. The banding patterns obtained from the SSR primers allowed most of the cultivars and lines to be distinguished, with the exception of vegetative clones. According to the dendrogram, the 27 pineapple cultivars and lines were clustered into three main clusters and four individual clusters. As expected, the dendrogram showed that derived cultivars and lines are closely related to their parental cultivars; the genetic relationships between pineapple cultivars agree with the genealogy of their breeding history. In addition, the analysis showed that there is no obvious correlation between SSR markers and morphological characters. In conclusion, SSR analysis is an efficient method for pineapple cultivar identification and can offer valuable informative characters to identify pineapple cultivars in Taiwan.

  17. Viabilidade da consorciação de pimentão com repolho, rúcula, alface e rabanete Feasibility of intercropping pepper with cabbage, rocket, lettuce and radish

    Directory of Open Access Journals (Sweden)

    Bráulio Luciano A Rezende

    2006-03-01

    Full Text Available O trabalho foi conduzido na UNESP, Jaboticabal-SP, de setembro/2003 a janeiro/2004, com objetivo de avaliar a viabilidade da consorciação de pimentão com as culturas de repolho, rúcula, alface e rabanete. O experimento constou de 15 tratamentos, correspondentes a 10 cultivos consorciados (combinações das cinco hortaliças e cinco monocultivos. Utilizou-se o delineamento experimental em blocos casualizados, com seis repetições. Foram utilizados os híbridos Magali R e Kenzan, respectivamente, para pimentão e repolho; e as cultivares Vera, Cultivada e Crimson Gigante, respectivamente, para alface, rúcula e rabanete. As produtividades de pimentão e repolho em cultivo consorciado não diferiram significativamente das obtidas em monocultivo. Maior massa fresca de parte aérea de plantas de alface (438,86 g/planta foi observada quando a alface foi consorciada com pimentão, diferindo estatisticamente dos demais cultivos que obtiveram em média 323,05 g/planta de alface. Aumento na produtividade de raízes comerciais de rabanete foi observado quando consorciado com pimentão, porém, foi significativamente superior apenas ao cultivo consorciado de pimentão+repolho+rabanete. A massa fresca da parte aérea da rúcula mostrou diferença estatística apenas entre os consórcios de pimentão+rúcula+alface e pimentão+repolho+rúcula. Exceto o consórcio pimentão+repolho que obteve índice de uso eficiente da terra (UET de 1,92; todos os outros consórcios apresentaram UET superior a 2,0, com maior UET (2,64 obtido no consórcio pimentão+alface. A superioridade de 92 a 164% na produção de alimento por área dos consórcios sobre os monocultivos, demonstra a viabilidade dos policultivos e maior eficiência do uso da terra.This work was carried out in Jaboticabal, São Paulo State, Brazil, from September 2003 to January 2004, to evaluate the feasibility of an intercropping system of pepper with cabbage, rocket, lettuce and radish, in relation

  18. Efeito da qualidade das sementes sobre a formação de mudas de alface Effect of seed quality on lettuce seedlings development

    Directory of Open Access Journals (Sweden)

    Simone M. Franzin

    2005-06-01

    Full Text Available Determinou-se o efeito da qualidade fisiológica das sementes sobre a formação de mudas de alface. Utilizaram-se dois lotes de sementes com diferentes níveis de qualidade inicial, das cultivares Regina e Vera, selecionados por meio dos testes de germinação, primeira contagem, envelhecimento acelerado, condutividade elétrica e emergência em "gerbox". Os efeitos dos níveis de qualidade sobre a produção de mudas foram avaliados por meio dos testes de índice de velocidade de emergência, número de folhas, altura da parte aérea, comprimento de raízes, massa úmida e seca das mudas e classificação do vigor das mudas. Utilizou-se o delineamento inteiramente casualizado, com os dados analisados pelo teste Tukey em 5% de probabilidade. Houve efeito favorável na qualidade das sementes das cultivares Regina e Vera para a formação de mudas aos 20 dias após a semeadura. Concluiu-se que sementes de alta qualidade fisiológica produzem maior percentagem de mudas vigorosas, com maior número de folhas, maior altura da parte aérea e comprimento de raízes e maior massa aos 20 dias de cultivo.The effect of the physiological quality of the seeds on lettuce seedlings was established. Two lots of lettuce seeds cv. Regina and Vera with different levels of initial quality were used. These lots were selected based upon germination tests: first score, fast aging, electrical conductivity and emergence in gerbox. The effects of the quality levels on the seedling production were evaluated through the parameters: speed rate emergence tests, number of leaves, height of the aerial part, root length, dry and wet mass of the seedlings and classification of the vitality of the seedlings. The experiment was carried out in a completely randomized design with four replications. Seed quality of the cultivars Regina and Vera have a positive effect on the formation of seedlings 20 days after sowing. High physiological quality seeds produce a higher percentage of

  19. BIODIVERSITY OF NATIONAL SQUASH CULTIVAR ACCESSIONS

    Directory of Open Access Journals (Sweden)

    A. F. Bukharov

    2017-01-01

    Full Text Available The squash is one of  the most  ancient plants, bearing numerous qualities. The squash gave high yield and is unpretentious plant, the fruit of which is long-stored and can be used as boiled, stewed, baked, fried product, and be added to bread, mush and pudding, and be prepared as puree, jam, candied fruit and other meals. Owing to useful characteristics the squash is a valuable source or raw  material for  food  canning  industry,  for  health-care and functional foodstuff production. Its best cultivar accessions contain to 30% of dry matter, to 12% of sugars  and  to  36%  of  carotene.  The  species  of  squash includes 4 subspecies and 20 varieties. One accession that came from Spain in 1937 served as an initial breeding accession for many other table cultivars for long time. For 80 years of national breeding program the many cultivars for  table  use have been released. There are the classic cultivars, such as ‘Mramornaya’, ‘Stolovaya Zimnaya’,  Gribovskaya Zimnaya’,  ‘Donskaya  Sladkaya’, ‘Michurinskaya’ that are selected or developed from first Spanish accession. This richness and originality of cultivar squash accessions should be carefully preserved. There are the new generation cultivars, such as ‘Kroshka’, ‘Malishka’,    ‘Rossiyanka’,    ‘Konfetka’,    ‘Moskvichka’, ‘Vnuchka’ and many others, which are short-tendrils and suitable for  modern  mechanized cultivation  technology. Moreover the development of new cultivars, bearing resistance to biotic and abiotic stress is the main goal of nearest breeding program.

  20. Morphological characteristic of purple long yard bean cultivars and their tolerance to drought stress

    Directory of Open Access Journals (Sweden)

    M W Lestari

    2015-01-01

    Full Text Available The cultivation of purple long yard bean which tolerance to drought stress and have high productivity can improve farming in arid area. The purpose of this study was to evaluate the mechanism of the tolerance purple long yard beans to drought stress based on morphologic characters, to get the hypothesis method of tolerance and to obtain tolerance cultivars to the drought stress. Eight cultivars of purple long yard beans, i.e. UBPHU1-41, UBPHU1-130, UBPU3-153, UBPU1-202, UBPU2-222, UBPU1-365, Brawijaya 4 and Bagong 2, were tested in two environmental conditions, 100% field capacity and 50% field capacity. The results showed that drought stress in purple long yard bean affected all morphological characters observed, except for root length and flowering time. Estimation of tolerance to drought stress using the Principles Component Analysis (PCA showed that the shoot fresh weight could be an indicator of purple pod bean tolerance to drought stress. However, the test using Stress Susceptibility Index (SSI was not able to classify the purple long yard bean tolerance to drought stress. The results of analysis using PCA followed by discriminant analysis and clustering dendrogram showed that the UBPU1-41, UBPU1-130, UBPU2-222, UBPU1-365, UB4 and Bagong 2 cultivars were medium cultivars that are tolerant to drought stress. Therefore, they can be planted in semiarid regions.

  1. Morphological, mechanical and antioxidant properties of Portuguese almond cultivars

    DEFF Research Database (Denmark)

    Oliveira, Ivo; Meyer, Anne S.; Afonso, Silvia

    2018-01-01

    The aim of this study was to evaluate morphological (of fruit and kernel), mechanical (namely shell rupture force) and antioxidant properties (including phenolics and flavonoid content) of five Portuguese almond cultivars, comparing them with two commercial cultivars (Glorieta and Ferragnès). Of ...... high kernel weight, low percentages of double kernels or losses during shelling and considerable higher phenolics and flavonoids content may be considered by industry during selection of almond.......). Of the analyzed traits, nut and kernel dimensions varied substantially and were used to describe cultivars. However, some traditional cultivars recorded similar (Pegarinhos), or even higher (Amendoão, Casanova and Refêgo) nut and kernel weight than commercial cultivars. Furthermore, shelling percentage...... of traditional cultivar (Bonita) was higher than commercial cultivars. Rupture force necessary to break fruits of all traditional cultivars was higher than commercial ones, and was correlated to nut weight cultivars. The phenolics, flavonoids content and antioxidants were higher for Casanova. Parameters like...

  2. Impact of agrochemicals on Peronospora sparsa and phenolic profiles in three Rubus arcticus cultivars.

    Science.gov (United States)

    Hukkanen, Anne; Kostamo, Katri; Kärenlampi, Sirpa; Kokko, Harri

    2008-02-13

    The main arctic bramble ( Rubus arcticus) cultivars are susceptible to downy mildew ( Peronospora sparsa), which seriously threatens the cultivation. The efficiency of Aliette, Euparen M, phosphite-containing Phosfik, Phostrol, Farm-Fos-44, and Kaliumfosfiet, as well as Bion was evaluated in the greenhouse. Fewer symptoms and less Peronospora DNA were found in plants treated with Euparen M and Bion, whereas Aliette, Phosfik, and Phostrol gave moderate protection. Three arctic bramble cultivars showed varying susceptibility to P. sparsa. An inexpensive and fast in vitro plate test gave results parallel with those obtained in the greenhouse. Quantitative differences were found in the phenolic profiles of the leaves of different cultivars and in different treatments. Several phenolic compounds were tentatively identified in arctic bramble for the first time, for example, monomeric and oligomeric ellagitannins and galloylglucoses. Negative correlation was found between the amount of P. sparsa DNA and flavonol glycosides and some ellagitannins in the leaves 8 days after inoculation, suggesting a possible role for these phenolics in the defense.

  3. Changes in cinnamyl alcohol dehydrogenase activities from sugarcane cultivars inoculated with Sporisorium scitamineum sporidia.

    Science.gov (United States)

    Santiago, Rocío; Alarcón, Borja; de Armas, Roberto; Vicente, Carlos; Legaz, María Estrella

    2012-06-01

    This study describes a method for determining cinnamyl alcohol dehydrogenase activity in sugarcane stems using reverse phase (RP) high-performance liquid chromatography to elucidate their possible lignin origin. Activity is assayed using the reverse mode, the oxidation of hydroxycinnamyl alcohols into hydroxycinnamyl aldehydes. Appearance of the reaction products, coniferaldehyde and sinapaldehyde is determined by measuring absorbance at 340 and 345 nm, respectively. Disappearance of substrates, coniferyl alcohol and sinapyl alcohol is measured at 263 and 273 nm, respectively. Isocratic elution with acetonitrile:acetic acid through an RP Mediterranea sea C18 column is performed. As case examples, we have examined two different cultivars of sugarcane; My 5514 is resistant to smut, whereas B 42231 is susceptible to the pathogen. Inoculation of sugarcane stems elicits lignification and produces significant increases of coniferyl alcohol dehydrogenase (CAD) and sinapyl alcohol dehydrogenase (SAD). Production of lignin increases about 29% in the resistant cultivar and only 13% in the susceptible cultivar after inoculation compared to uninoculated plants. Our results show that the resistance of My 5514 to smut is likely derived, at least in part, to a marked increase of lignin concentration by the activation of CAD and SAD. Copyright © Physiologia Plantarum 2012.

  4. Tagging microsatellite marker to a blast resistance gene in the irrigated rice cultivar Cica-8

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    Thiago Martins Pinheiro

    2012-09-01

    Full Text Available The rice cultivar Cica-8 exhibit differential reaction to several pathotypes of Magnaporthe oryzae. The objective of the present investigation was to determine the number of alleles involved in the expression of resistance to leaf blast and identify microsatellite markers linked to these alleles. A cross between cultivar Metica-1 and Cica-8 susceptible and resistant, respectively, to pathotype IB-1 (Py1049 was made to obtain F1, F2, BC1:1 and BC1:2 progenies. Greenhouse tests for leaf blast reaction showed that resistance is controlled by a monogenic dominant gene. For testing microsatellite markers, DNA of both resistant and susceptible parents and F1 and F2 populations was extracted. As expected for single dominant gene the F2 populations segregated at a ratio of 3:1. Of the 11 microsatellite markers tested, one marker RM 7102 was found to be closely linked to the resistant allele at a distance of 2.7 cM, in the cultivar Cica-8 to pathotype IB-1.

  5. Salt Tolerance of Six Switchgrass Cultivars

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    Youping Sun

    2018-04-01

    Full Text Available Panicum virgatum L. (switchgrass cultivars (‘Alamo’, ‘Cimarron’, ‘Kanlow’, ‘NL 94C2-3’, ‘NSL 2009-1’, and ‘NSL 2009-2’ were evaluated for salt tolerance in two separate greenhouse experiments. In experiment (Expt. 1, switchgrass seedlings were irrigated with a nutrient solution at an electrical conductivity (EC of 1.2 dS·m−1 (control or a saline solution (spiked with salts at an EC of 5.0 dS·m−1 (EC 5 or 10.0 dS·m−1 (EC 10 for four weeks, once a week. Treatment EC 10 reduced the tiller number by 32% to 37% for all switchgrass cultivars except ‘Kanlow’. All switchgrass cultivars under EC 10 had a significant reduction of 50% to 63% in dry weight. In Expt. 2, switchgrass was seeded in substrates moistened with either a nutrient solution of EC 1.2 dS·m−1 (control or a saline solution of EC of 5.0, 10.0, or 20.0 dS·m−1 (EC 5, EC 10, or EC 20. Treatment EC 5 did not affect the seedling emergence, regardless of cultivar. Compared to the control, EC 10 reduced the seedling emergence of switchgrass ‘Alamo’, ‘Cimarron’, and ‘NL 94C2-3’ by 44%, 33%, and 82%, respectively. All switchgrass cultivars under EC 10 had a 46% to 88% reduction in the seedling emergence index except ‘NSL 2009-2’. No switchgrass seedlings emerged under EC 20. In summary, high salinity negatively affected switchgrass seedling emergence and growth. Dendrogram and cluster of six switchgrass cultivars indicated that ‘Alamo’ was the most tolerant cultivar, while ‘NSL 2009-2’ was the least tolerant cultivar at both seedling emergence and growth stages. A growth-stage dependent response to salinity was observed for the remaining switchgrass cultivars. ‘NSL 2009-1’ and ‘NL 94C2-3’ were more tolerant to salinity than ‘Cimarron’ and ‘Kanlow’ at the seedling emergence stage; however, ‘Kanlow’ and ‘Cimarron’ were more tolerant to salinity than ‘NSL 2009-1’ and ‘NL 94C2-3’ at the seedling growth

  6. Evaluation of Compatibility and Morpho–Physiological Characteristics of Some Olive Cultivars (Oleaeuropaea L. at Tarom Climate

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    mahmoud azimi

    2017-02-01

    , Koroneiki, Konservolia, Leccino, Mary, Mastoidis, Manzanilla, and Mission. The experiment was conducted based on a RCBD layout with three replications considering four trees for each plot. Vegetative characters (tree vigor, growth habit and crown density, flower traits (number of flower per inflorescence, number of inflorescence per shoot, perfect flower and fruit characters (fruit weight, length and diameter of fruit, stone weight, flesh to stone ratio, oil percent in dry fruit weight and yield per hectare as well as susceptibility of crown trees to wind and susceptibility to cold, along with the cumulative yield of 5-year were measured. For statistical analysis the SAS software was used and means comparisons were performed using Duncan Multiple Range Test. Results and Discussion: Results showed that among evaluated cultivars, the number of flowers per inflorescence in most cultivars except Leccino, Baladiand Koroneiki were the same level. Manzanillaand Mission had the highestflowers per inflorescence but Leccino and Baladi had the lowest number of flowers per inflorescence. Arbequina, Koroneiki, Baladi, Zard, Konservolia, PicualandRoghany in comparison with other cultivars had high perfect flowers. Konservolia, Zard, Koroneiki, Arbequinaand Abusatl had the highest yield. Theyield of these cultivars was 4265, 3498, 3104, 2625, 2273and2101kg per hectare, respectively. The cumulative yield of abovementioned cultivars in5-year were 22472, 17490, 15520, 13125, 11365and10505 Kg/ha, respectively. Amigdalolia, Konservolia, Baladiand Mastoidis cultivars had the highest oil content in dry matter basis. Also Mari, Koroneiki and Arbequina cultivars had the highest oil content. Fruit weight of Amigdalolia, Abusatl and Konservolia cultivars were more than 8 gr. More over Picual, Zard, Mission and Manzanilla cultivars fruit weight were between 5 and 6 gr. Konservolia, Abusatl, Manzanilla, Amygdalolia, Picual and Mastoidis had the highest flesh to stone ratio. The flesh to stone ratio of

  7. Assessing nitrogen supply potential and influence on growth of lettuce and amaranthus of different aged composts

    International Nuclear Information System (INIS)

    Akhtar, M.J.; Young, I.; Irvine, R.J.; Sturrock, C.

    2010-01-01

    This study assessed the potential of different composts at different maturity stages to supply N and their effect on the vegetative growth of lettuce and Amaranthus. Five composts aged 1, 3, 6, 9, and 12 months, were mixed with soil at the rate of 5%, 10% and 15% then seeded with lettuce and Amaranthus. Results showed that 1, 3 and 6 month aged composts had a negative effect on plant height of lettuce and Amaranthus as 1-15.78% and 4.78 to 29.45% decrease in plant height over control was recorded respectively. On the other hand 9 and 12 month aged composts had a significant positive effect on plant height of lettuce and Amaranthus where 43.48% and 34.8% increase over control was recorded with the application of 15% of 12 month aged compost respectively. A similar effect was observed on fresh biomass of both lettuce and Amaranthus where a 386% and 59.43% increase over control was recorded with the application of 15% of 12 month aged compost respectively. One and three month aged composts revealed a negative effect on N absorption by lettuce whereas 1, 3, 6 and 9 month aged composts had a negative effect on N absorption by Amaranthus. 30.39% and 21.48% increases over control in N absorption by lettuce and Amaranthus respectively were recorded with the application of 15% of 12 month aged compost. (author)

  8. Sampling Plans for the Thrips Frankliniella schultzei (Thysanoptera: Thripidae) in Three Lettuce Varieties.

    Science.gov (United States)

    Silva, Alisson R; Rodrigues-Silva, Nilson; Pereira, Poliana S; Sarmento, Renato A; Costa, Thiago L; Galdino, Tarcísio V S; Picanço, Marcelo C

    2017-12-05

    The common blossom thrips, Frankliniella schultzei Trybom (Thysanoptera: Thripidae), is an important lettuce pest worldwide. Conventional sampling plans are the first step in implementing decision-making systems into integrated pest management programs. However, this tool is not available for F. schultzei infesting lettuce crops. Thus, the objective of this work was to develop a conventional sampling plan for F. schultzei in lettuce crops. Two sampling techniques (direct counting and leaf beating on a white plastic tray) were compared in crisphead, looseleaf, and Boston lettuce varieties before and during head formation. The frequency distributions of F. schultzei densities in lettuce crops were assessed, and the number of samples required to compose the sampling plan was determined. Leaf beating on a white plastic tray was the best sampling technique. F. schultzei densities obtained with this technique were fitted to the negative binomial distribution with a common aggregation parameter (common K = 0.3143). The developed sampling plan is composed of 91 samples per field and presents low errors in its estimates (up to 20%), fast execution time (up to 47 min), and low cost (up to US $1.67 per sampling area). This sampling plan can be used as a tool for integrated pest management in lettuce crops, assisting with reliable decision making in different lettuce varieties before and during head formation. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. The effect of growth conditions on flavonols and anthocyanins accumulation in green and red lettuce

    Directory of Open Access Journals (Sweden)

    Klaudia BRÜCKOVÁ

    2016-12-01

    Full Text Available The aim of the study was to investigate the effect of different growth conditions on anthocyanins and flavonols accumulation in leaves of green and red loose leaf lettuce (Lactuca sativa var. crispa. Lettuce plants were grown in three types of conditions, in greenhouse (I. variant, behind clear glass in field (II. variant and in open field conditions (III. variant. Estimation of anthocyanins and flavonols content was done by non-destructive measurements with optical fluorescence sensor Multiplex® 3 (Force-A, France. It was estimated that green lettuce varieties had a greater flavonols content compared to red lettuce varieties in all experimental variants. The highest level of flavonols was detected in leaves of green variety Zoltán (1.218 RU and in red lettuce had the highest amount of flavonols in variety Carmesi (1.095 RU. At the same time red lettuce varieties were characterized by higher anthocyanins content. Parameter anthocyanin index is correlated with visible red coloration of leaves. The highest content of anthocyanins was detected in variety Oakly (0.867 RU. Under the open field conditions was found statistically significant higher (P < 0.05 flavonols and anthocyanins level in both green and red lettuce leaves compared to greenhouse conditions. It may be connected with intensification of flavonoids biosynthesis and accumulation which normally stimulated by sun irradiation, especially UV-B radiation.

  10. POTENCIAL PRODUTIVO DE CULTIVARES DE MORANGUEIRO

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    AMANDA GONÇALVES GUIMARÃES

    2015-03-01

    Full Text Available RESUMO O objetivo foi avaliar o potencial produtivo de cultivares de morangueiro em região representativa do Alto Jequitinhonha. O experimento foi conduzido na fazenda Mape Frutas Ltda., localizada no município de Datas-MG, em delineamento em blocos ao acaso, com oito cultivares de morangueiro em quatro repetições, para verificar a produção de mudas e de frutos. A contagem da produção de estolões e de mudas foi realizada aos 180 dias após o plantio. A avaliação das variáveis relacionadas à produção de frutos foi feita duas vezes por semana, no período de maio a outubro de 2012. Das cultivares de dias curtos (Festival, Campinas, Toyonoka, Dover, Oso Grande e Camarosa e dias neutros (Diamante e Aromas, apenas Toyonoka foi a que apresentou menor desempenho para as variáveis. A significativa superioridade das cultivares Camarosa e Festival, para praticamente todas as variáveis avaliadas, permite recomendá-las para regiões com características edafoclimáticas semelhantes às da região onde o experimento foi conduzido. Dentre as cultivares avaliadas, as mais precoces tenderam a apresentar maior desempenho para variáveis relacionadas à produção de frutos.

  11. Neural Network Modeling to Predict Shelf Life of Greenhouse Lettuce

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    Wei-Chin Lin

    2009-04-01

    Full Text Available Greenhouse-grown butter lettuce (Lactuca sativa L. can potentially be stored for 21 days at constant 0°C. When storage temperature was increased to 5°C or 10°C, shelf life was shortened to 14 or 10 days, respectively, in our previous observations. Also, commercial shelf life of 7 to 10 days is common, due to postharvest temperature fluctuations. The objective of this study was to establish neural network (NN models to predict the remaining shelf life (RSL under fluctuating postharvest temperatures. A box of 12 - 24 lettuce heads constituted a sample unit. The end of the shelf life of each head was determined when it showed initial signs of decay or yellowing. Air temperatures inside a shipping box were recorded. Daily average temperatures in storage and averaged shelf life of each box were used as inputs, and the RSL was modeled as an output. An R2 of 0.57 could be observed when a simple NN structure was employed. Since the "future" (or remaining storage temperatures were unavailable at the time of making a prediction, a second NN model was introduced to accommodate a range of future temperatures and associated shelf lives. Using such 2-stage NN models, an R2 of 0.61 could be achieved for predicting RSL. This study indicated that NN modeling has potential for cold chain quality control and shelf life prediction.

  12. Carrot, Corn, Lettuce and Soybean Nutrient Contents are ...

    Science.gov (United States)

    Biochar, the carbon-rich material remaining after pyrolysis of cellulosic and manure feedstocks, has the potential as a soil amendment to sequester carbon and to improve soil water-holding and nutrient properties- thereby enhancing plant growth. However, biochar produced from some feedstocks also could adversely affect crop quality by changing soil pH and reducing nutrients (e.g., Ca, K, Mg, N, Na, and P) in plant tissues. To evaluate effects of biochar on the nutrient quality of four crops, we conducted a greenhouse study using pots with: carrot (Daucus carota cv. Tendersweet), corn (Zea mays, cv. Golden Bantam), lettuce (Lactuca sativa, cv. Black-Seeded Simpson) and soybean (Glycine max cv. Viking 2265). Plants were grown in one of two South Carolina sandy Coastal Plain soils (Norfolk and Coxville Soil Series), along with biochar (1% by weight) produced from pine chips (PC), poultry litter (PL), swine solids (SS), switchgrass (SG), and two blends of pine chips plus poultry litter (PC/PL, 50/50% and 80/20%). Each of the feedstocks and feedstock blends was pyrolyzed at 350, 500, and 700 ̊ C to produce the biochar used to amend the Norfolk and Coxville soils. Effects of biochar on leaf nutrients (% dry weight) statistically varied with species, soil, feedstock and temperature and nutrient. For carrot and lettuce, the PL, PL/PC, and SS biochars generally decreased leaf N, Ca, Mg, and P; while PL and PL/PC increased K and Na. Biochars had little effect on lea

  13. Mannanase production by the lettuce endosperm : Control by the embryo.

    Science.gov (United States)

    Halmer, P; Bewley, J D

    1979-01-01

    Endo-β-mannanase (EC 3.2.1.78) is produced and secreted by the cells of the endosperm of lettuce (lactuca sativa L.) "seeds" (achenes). In imbibed intact seeds, production is prevented by inhibitors. If the endosperm is incubated alone, these inhibitors can be removed by leaching, allowing mannanase production. Abscisic acid, a component of lettuce seeds, inhibits the production of mannanase in the isolated endosperm, and may be involved in regulation of mannanase production in intact seeds. During germination the inhibition is removed, beginning 4-8 h after red-light irradiation, which was given 4 h from sowing. The cotyledons participate in this process, and are controlled by events occuring in the axis within 4 h from red-light irradiation. This control by the axis apparently depends on the exchange of diffusible substances. Both benzyladenine and gibberellic acid can replace the influence of the axis if the latter is removed, and may therefore be involved in the control by the axis of the rest of the seed.

  14. Yield of lettuce grown in aquaponic system using different substrates

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    Rodrigo A. Jordan

    Full Text Available ABSTRACT In the aquaponic system, the characteristics of the materials used as substrate directly affect plant development, because besides acting as a support base, they must present a surface to fix microorganisms, responsible for the conversion of nutrients into forms more easily available to plants. Thus, the objective of this study was to evaluate the effect of four growing substrates on the yield of lettuce grown in aquaponic system. The experimental design was randomized blocks with four treatments, which corresponded to the substrates, and six replicates. Plants were grown using the nutrient film technique (NFT system. The substrates used in the experiment were: coconut shell fiber with crushed stone #3, expanded vermiculite, zeolite and phenolic foam. The treatment with phenolic foam was considered as the least suitable for lettuce cultivation in aquaponic system, because it caused lower yield (20.8 t ha-1. The treatment using coconut shell fiber with crushed stone #3 was considered as the most adequate, since it led to higher yield (39.9 t ha-1 compared with the other substrates analyzed.

  15. Impact of phytopathogen infection and extreme weather stress on internalization of Salmonella Typhimurium in lettuce.

    Science.gov (United States)

    Ge, Chongtao; Lee, Cheonghoon; Nangle, Ed; Li, Jianrong; Gardner, David; Kleinhenz, Matthew; Lee, Jiyoung

    2014-01-03

    Internalization of human pathogens, common in many types of fresh produce, is a threat to human health since the internalized pathogens cannot be fully inactivated/removed by washing with water or sanitizers. Given that pathogen internalization can be affected by many environmental factors, this study was conducted to investigate the influence of two types of plant stress on the internalization of Salmonella Typhimurium in iceberg lettuce during pre-harvest. The stresses were: abiotic (water stress induced by extreme weather events) and biotic (phytopathogen infection by lettuce mosaic virus [LMV]). Lettuce with and without LMV infection were purposefully contaminated with green fluorescence protein-labeled S. Typhimurium on the leaf surfaces. Lettuce was also subjected to water stress conditions (drought and storm) which were simulated by irrigating with different amounts of water. The internalized S. Typhimurium in the different parts of the lettuce were quantified by plate count and real-time quantitative PCR and confirmed with a laser scanning confocal microscope. Salmonella internalization occurred under the conditions outlined above; however internalization levels were not significantly affected by water stress alone. In contrast, the extent of culturable S. Typhimurium internalized in the leafy part of the lettuce decreased when infected with LMV under water stress conditions and contaminated with high levels of S. Typhimurium. On the other hand, LMV-infected lettuce showed a significant increase in the levels of culturable bacteria in the roots. In conclusion, internalization was observed under all experimental conditions when the lettuce surface was contaminated with S. Typhimurium. However, the extent of internalization was only affected by water stress when lettuce was infected with LMV. © 2013.

  16. Quantitative control of Lettuce mosaic virus fitness and host defence inhibition by P1-HCPro P1-HC Pro do Lettuce mosaic virus atua de forma quantitativa na inibição da resposta de defesa do hospedeiro e adaptação viral

    Directory of Open Access Journals (Sweden)

    Renate Krause-Sakate

    2007-06-01

    Full Text Available Two Lettuce mosaic virus isolates capable of overcoming the resistance afforded by the resistance gene mo1² in lettuce, LMV-AF199 from Brazil, and LMV-E, an European isolate, were evaluated for the rapidity and severity of symptoms induced on the lettuce variety Salinas 88 (mo1². The mosaic symptoms on Salinas 88 plants inoculated with LMV-AF199 appeared 7 days post-inoculation (dpi and 15 dpi for LMV-E. The symptoms induced by LMV-AF199 in this cultivar were also more severe than those induced by LMV-E. In order to identify the region of the viral genome responsible for this phenotype, recombinant viruses were constructed between these isolates and the phenotype of each recombinant was analysed. The region encoding proteins P1 and HcPro from LMV-AF199 was associated with the increased virulence in Salinas 88.Dois isolados de Lettuce mosaic virus capazes de contornar a resistência conferida pelo gene mo1² em alface, LMV-AF199 proveniente do Brasil e LMV-E um isolado europeu, foram avaliados quanto à rapidez e à severidade dos sintomas induzidos em alface variedade Salinas 88 (mo1². Os sintomas de mosaico induzidos pelo isolado LMV-AF-199 em Salinas 88 são mais severos e aparecem aos 7 dias após a inoculação (dpi, enquanto que para o isolado LMV-E os sintomas são visíveis somente a partir dos 15 dpi. Com o intuito de identificar a região do genoma viral responsável por este fenótipo, vírus recombinantes foram construídos entre estes dois isolados, e o fenótipo avaliado quanto a rapidez e severidade dos sintomas em Salinas-88. A região codificadora para as proteínas P1 e Hc-Pro do LMV-AF199 foi associada com o aumento da virulência deste isolado em Salinas-88.

  17. Molecular characterization of rye cultivars

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    Želmíra Balážová

    2016-01-01

    Full Text Available 14.00 The results of molecular analysis of 45 rye taxa (Secale cereale L. represented by agricultural varieties originated from Central Europe and the Union of Soviet Socialist Republics (SUN are presented. The genetic diversity of rye cultivars by 6 SSR markers was evaluated. Six specific microsatellite primer pairs produced 58 polymorphic alleles with an average of 9.7 alleles per locus. The number of alleles ranged from 6 (SCM2 to 14 (SCM86. Genetic polymorphism was characterized based on diversity index (DI, probability of identity (PI and polymorphic information content (PIC. The diversity index (DI of SSR markers ranged from 0.5478 (SCM2 to 0.887 (SCM86 with an average of 0.778. The lowest value of polymorphic information content was recorded for SCM2 (0.484 and the highest value for SCM86 (0.885 of PIC was detected in SCM86 with an average of 0.760.The dendrogram of genetic similarity was constructed, based on UPGMA algorithm. The hierarchical cluster analysis divided rye genotypes into 4 main clusters. The first cluster of 14 genotypes was subdivided in two subclusters (1a and 1b where 50% of genotypes were Czechoslovak origin. The second cluster contained four genotypes were three (75% of them had Czech or Czechoslovak origin. In the third subcluster separated three rye genotypes of different origin. The rest (24 of rye genotypes in the fourth cluster were divided into two subclusters (4a and 4b where clearly separated group of Polish (4aa and Czech and Czechoslovak (4ab genotypes. Two genotypes of 4aa subcluster (Wojcieszyckie and Dankowskie Nowe from Poland were genetically the closest. In the dendrogram alle genotypes were differentiated and clustering partially reflects geographic origin of studied rye genotypes. In this experiment, SSRs markers proved to be a high informative and usefull tool in genetic diversity research for the distinguishing and characterization of close related varieties. Normal 0 21 false false false CS JA X-NONE

  18. FIRE BLIGHT SUSCEPTIBILITY OF SOME PEAR VARIETIES (ERWINIA AMYLOVORA, BURILL

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    Zsolt Jakab- Ilyefalv

    2012-01-01

    Full Text Available At Bistriţa Fruit Research and Development Station, in a pear collection, planted with 44 varieties, there has been studied the susceptibility to fire blight (Erwinia amylovora,Burill. During the vegetation period, phytosanitary treatments to control the disease have been applied using copper based products (copper sulfate, Champion, Funguran, Kocide. Erwinia amylovora infections have been influenced by the rainfall registered in April (70.9 mm and May (104.7 mm and the temperature fluctuations in April-May. The field observations on Erwinia amylvora attack demonstrate that the pear varieties have a different susceptibility to this dangerous bacterium. Evaluation of attack level in the pear collection was done using an evaluation scale with 9 scores using a reference resistance scale for : ‘Highly resistant’ , ‘Moderately resistant’, ‘Susceptible’, ‘Very susceptible’ cultivars . The most sensitive pear varieties in the collection were: ‘De Noiembrie’, ‘Abatele Fetel’, ’Daciana’, ’Triumf’, ’Williams Boway’, ’Margareta Marillat’, ’Beauty Tomme’, ‘Williams rosu’, ’Aromata de Bistrita’, ’Jeanne d`Arc’, ’Aramiu de Somes’, ’Belle des Arbres’, ’Zorka’ representing 13.64% of the total pear varieties. In several cultivars there have been observed increased symptoms, a very high susceptibility of infections leading to complete scorching of trees: Jeanne d`Arc’, Williams rosu’, ‘Triumf’, ‘Aromata de Bistrita’, ‘Zorka’. Strong attack symtoms were observed at the pear cultivars ‘Cure’, ‘Euras, ’Ciuda’ ‘Highland’, ‘Precoce Morettini’, ’Monica’, ’Cadillac’, ’Juliana’, ’Somesan’, ’Beurré Hardenpont’ these cultivars being susceptible to Erwinia amylovora , representing 40.91 % of total genotypes . Cultivars ‘Untoasa Geoagiu’, ‘Beurre Hardy’, ‘Trivale’ manifested a certain tolerance to Erwinia amylovora , no attack symptoms being

  19. Flutuação populacional do bicho-mineiro em cultivares de café arábica resistentes à ferrugem Fluctuation of leaf miner population in resistant arabica coffee cultivars to leaf rust

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    Celso Henrique Costa Conceição

    2005-01-01

    Full Text Available A intensidade de infestação pelo bicho-mineiro, Leucoptera coffeella (Guérin-Méneville (Lepidoptera: Lyonetiidae foi investigada nas cultivares Obatã IAC 1669-20 e Tupi IAC 1669-33, com resistência à ferrugem das folhas do cafeeiro, Hemileia vastatrix Berk. et Br., e Ouro Verde Amarelo IAC 4397, suscetível à doença, em ensaios de campo, localizados em Campinas (SP, Brasil. A incidência de ferrugem e a ocorrência de inimigos naturais da praga, assim como o enfolhamento das plantas, foram também observados nas três cultivares. As curvas de flutuação populacional obtidas para Obatã IAC 1669-20 e Tupi IAC 1669-33 revelaram maior incidência do bicho-mineiro entre abril e novembro. Já na cultivar Ouro Verde Amarelo IAC 4397, observaram-se dois picos de infestação, sendo o primeiro em abril-maio e o segundo em agosto-setembro. No entanto, a elevada percentagem de folhas minadas nas cultivares Tupi IAC 1669-33 e Obatã IAC 1669-20 em relação à Ouro Verde Amarelo IAC 4397 não é evidência de maior suscetibilidade à praga, mas sim devido à maior retenção foliar dessas cultivares, em conseqüência da resistência à ferrugem das folhas observada em ambas. De maneira oposta, na cultivar Ouro Verde Amarelo IAC 4397, os sintomas de ataque do bicho-mineiro ocorreram em menor nível especialmente devido a maior queda de folhas. Com base nas diferenças observadas entre as cultivares, sugere-se a adoção de estratégias distintas de manejo da praga.The intensity of infestation of leaf-miner, Leucoptera coffeella (Guérin-Méneville was investigated in coffee cultivars Obatã IAC 1669-20 and Tupi IAC 1669-33, both resistant to the leaf rust agent, Hemileia vastatrix Berk. et Br., and Ouro Verde Amarelo IAC 4397, susceptible to this coffee disease, at field assays in Campinas, SP, Brazil. The incidence of coffee rust and presence of natural enemies, as well as the plant leafiness, were also observed. In Obatã IAC 1669-20 and Tupi

  20. Qualidade de mudas de alface em função de substratos com e sem biofertilizante Quality of lettuce seedlings depending on substrates with and without biofertilizer addition

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    Damiana Cleuma de Medeiros

    2008-06-01

    Full Text Available Avaliou-se a qualidade de mudas de alface em função de substratos com e sem biofertilizante (aplicado aos 6; 12 e 18 dias após germinação em condições de casa-de-vegetação. O experimento foi conduzido em esquema fatorial inteiramente casualizado: 3 cultivares (Babá-de-Verão, Grand Rapids e Grandes Lagos x 3 tipos de substratos (areia lavada, composto orgânico e substrato comercial Plantmax® x 2 (com e sem biofertilizante, com quatro repetições. A avaliação foi feita aos 24 dias da germinação através de número de folhas, altura da parte aérea, comprimento da raiz, massa seca da parte aérea e massa seca da raiz. Houve efeito isolado dos fatores cultivares e substratos para número de folhas e comprimento da raiz. Houve efeito de interação cultivares x substratos para altura da parte aérea, massa seca da parte aérea e massa seca da raiz. Dentre as variáveis analisadas a cultivar Grand Rapids e o substrato composto orgânico foi a que obteve melhor resultado. Não houve influência significativa da aplicação de biofertilizante.The quality of lettuce seedlings depending on substrates and biofertilizer addition (at 6; 12 and 18 days after germination, under greenhouse conditions was evaluated. The experiment was carried out in a completely randomized factorial scheme: 3 cultivars (Babá-de-Verão, Grand Rapids and Great Lakes x 3 substrates (washed sand, organic compost and commercial substrate Plantmax® x 2 (with and without biofertilizer addition, with four replications. The evaluation was done on 24-day old seedlings through number of leaves, shoot height, root length, shoot dry mass and root dry mass. There was an isolated effect for cultivars and substrates with regard to the number of leaves and root length. There was cultivars x substrates interaction effect for shoot height, shoot dry mass and root dry mass. The best result was obtained with cultivar Grands Rapids grown in organic compost. There were no

  1. Phloem sap collection from lettuce (Lactuca sativa L.): Methodology and yield.

    Science.gov (United States)

    van Helden, M; Tjallingii, W F; van Beek, T A

    1994-12-01

    Three methods to collect phloem sap on different lettuce lines were optimized and are described in detail. The success ratio for stylectomy of aphids was over 80% through the combination of a specially designed setup and electrical penetration graphs to monitor phloem sap ingestion. For unknown reasons on some lettuce lines stylets never showed sustained exudation. There were clear differences in stylet exudation between two aphid species on the same lettuce line. Honeydew collection in hexadecane made accurate quantitative analysis possible; samples were large and clean, but biotransformed. The EDTA chelation method produced large samples, but dilution, oxidation, and impurities from the wound surface reduced the reliability.

  2. Sensory profile of eleven peach cultivars

    Directory of Open Access Journals (Sweden)

    Francine Lorena Cuquel

    2012-03-01

    Full Text Available The goal of this study was to evaluate the sensory profile of eleven peach cultivars grown in an experimental orchard located in the city of Lapa (PR, Brazil in two seasons. The peach cultivars analyzed were Aurora I, Chimarrita, Chiripá, Coral, Eldorado, Granada, Leonense, Maciel, Marli, Premier, and Vanguarda. The sensory analysis was performed by previously trained panelists; 20 of them in the first season and 10 in the second season. The sensory evaluation was performed using Quantitative Descriptive Analysis, in which the following attributes were measured: appearance, aroma, flesh color, flesh firmness, flavor, and juiciness. The results showed preference for sweet, soft, and juicy fruits. Chimarrita, Chiripá, and Coral fruits showed better sensorial performance than the other peach cultivars. It was also verified that the analysis of the attributes aroma, flesh firmness, and flavor is enough for performing the sensory profile of peach fruits for in natura consumption.

  3. Persistence and Dissipation of Chlorpyrifos in Brassica Chinensis, Lettuce, Celery, Asparagus Lettuce, Eggplant, and Pepper in a Greenhouse

    Science.gov (United States)

    Lu, Meng-Xiao; Jiang, Wayne W.; Wang, Jia-Lei; Jian, Qiu; Shen, Yan; Liu, Xian-Jin; Yu, Xiang-Yang

    2014-01-01

    The residue behavior of chlorpyrifos, which is one of the extensively used insecticides all around the world, in six vegetable crops was assessed under greenhouse conditions. Each of the vegetables was subjected to a foliar treatment with chlorpyrifos. Two analytical methods were developed using gas chromatography equipped with a micro-ECD detector (LOQ = 0.05 mg kg−1) and liquid chromatography with a tandem mass spectrometry (LOQ = 0.01 mg kg−1). The initial foliar deposited concentration of chlorpyrifos (mg kg−1) on the six vegetables followed the increasing order of brassica chinensischlorpyrifos showed differences among the six selected vegetable plants, ranging from 16.5±0.9 mg kg−1 (brassica chinensis) to 74.0±5.9 mg kg−1 (pepper plant). At pre-harvest interval 21 days, the chlorpyrifos residues in edible parts of the crops were chlorpyrifos were found to be 7.79 (soil), 2.64 (pepper plants), 3.90 (asparagus lettuce), 3.92 (lettuce), 5.81 (brassica chinensis), 3.00 (eggplant plant), and 5.45 days (celery), respectively. The dissipation of chlorpyrifos in soil and the six selected plants was different, indicating that the persistence of chlorpyrifos residues strongly depends upon leaf characteristics of the selected vegetables. PMID:24967589

  4. Competitividade de cultivares de arroz irrigado com cultivar simuladora de arroz-vermelho

    OpenAIRE

    Balbinot Junior,Alvadi Antonio; Fleck,Nilson Gilberto; Menezes,Valmir Gaedke; Agostinetto,Dirceu

    2003-01-01

    Características morfológicas e fisiológicas de plantas cultivadas podem afetar sua habilidade competitiva com plantas daninhas. Este trabalho objetivou investigar a competitividade de cultivares de arroz irrigado (Oryza sativa L.) com cultivar simuladora de arroz-vermelho. Investigou-se na safra 2000/2001 o comportamento de oito genótipos de arroz, cultivados na presença ou ausência da cultivar de arroz EEA 406, que simulou infestação de arroz-vermelho. Aos 45 e aos 60 dias após a semeadura, ...

  5. Rapid identification of red-flesh loquat cultivars using EST-SSR markers based on manual cultivar identification diagram strategy.

    Science.gov (United States)

    Li, X Y; Xu, H X; Chen, J W

    2014-04-29

    Manual cultivar identification diagram is a new strategy for plant cultivar identification based on DNA markers, providing information to efficiently separate cultivars. We tested 25 pairs of apple EST-SSR primers for amplification of PCR products from loquat cultivars. These EST-SSR primers provided clear amplification products from the loquat cultivars, with a relatively high transferability rate of 84% to loquat; 11 pairs of primers amplified polymorphic products. After analysis of 24 red-fleshed loquat accessions, we found that only 7 pairs of primers could clearly separate all of them. A cultivar identification diagram of the 24 cultivars was constructed using polymorphic bands from the DNA fingerprints and EST-SSR primers. Any two of the 24 cultivars could be rapidly separated from each other, according to the polymorphic bands from the cultivars; the corresponding primers were marked in the correct position on the cultivar identification diagram. This red-flesh loquat cultivar identification diagram can separate the 24 red-flesh loquat cultivars, which is of benefit for loquat cultivar identification for germplasm management and breeding programs.

  6. Preliminary Evaluation of Some Elicited Apple Genotypes Candidate as Cultivars Using Morphological and Molecular Markers

    Directory of Open Access Journals (Sweden)

    Bayan Muzher

    2016-05-01

    Full Text Available Preliminary evaluation of 5 apple genotypes produced by seed selection in the germplasm of seed rootstocks in Sweida- Syria was carried out between 2005 and 2012, to study date of full flowering, maturity time, morphological characters of tree, shoots, leaves, flowers, and fruits, including chemical analysis. On the other hand, yield efficiency, fruit storability and the susceptibility to pests and physiological disorders were evaluated. Molecular characterization was achieved by using 8 pairs of SSR primers for the 5th genotypes in comparison with the two main commercial cultivars "Golden Delicious" and "Starking Delicious" to determine the genetic relationship between the studied genotypes and cultivars. The results divided the studied genotypes depending on the time of ripening into three groups: early, intermediate and late genotypes. All studied genotypes gave efficient and regular yield, and showed fixable fruit shape and size with variable storability due to maturity time. Molecular characterization reveled the ability of SSR technique to determine the genetic variation between the studied genotypes, the 8 primer pairs produced 22 alleles, 21 of them were polymorphic (95.45%. Cluster analysis divided the studied genotypes into 2 clusters, the first cluster included the two commercial cultivars Starking delicious and Golden delicious with one genotypes, while the second cluster contained the four remaining genotypes. Finally, the studied genotypes revealed high desired quantitative and qualitative traits, which assess to distribute these genotypes as new cultivars, and SSR technique was able to identify and revealed the genetic distance between the studied genotypes and commercial cultivars.INTERNATIONAL JOURNAL OF ENVIRONMENTVolume-5, Issue-2, March-May 2016, page: 98-109

  7. Secondary Metabolic Profiles of Two Cultivars of Piper nigrum (Black Pepper) Resulting from Infection by Fusarium solani f. sp. piperis.

    Science.gov (United States)

    da Luz, Shirlley F M; Yamaguchi, Lydia F; Kato, Massuo J; de Lemos, Oriel F; Xavier, Luciana P; Maia, José Guilherme S; Ramos, Alessandra de R; Setzer, William N; da Silva, Joyce Kelly do R

    2017-12-07

    Bragantina and Cingapura are the main black pepper ( Piper nigrum L.) cultivars and the Pará state is the largest producer in Brazil with about 90% of national production, representing the third largest production in the world. The infection of Fusarium solani f. sp. piperis , the causal agent of Fusarium disease in black pepper, was monitored on the cultivars Bragantina (susceptible) and Cingapura (tolerant), during 45 days' post infection (dpi). Gas Chromatography-Mass spectrometry (GC-MS) analysis of the volatile concentrates of both cultivars showed that the Bragantina responded with the production of higher contents of α-bisabolol at 21 dpi and a decrease of elemol, mostly at 30 dpi; while Cingapura displayed an decrease of δ-elemene production, except at 15 dpi. The phenolic content determined by the Folin Ciocalteu method showed an increase in the leaves of plants inoculated at 7 dpi (Bragantina) and 7-15 dpi (Cingapura); in the roots, the infection caused a phenolic content decrease in Bragantina cultivar at 45 dpi and an increase in the Cingapura cultivar at 15, 30 and 45 dpi. High Performance Liquid Chromatography-Mass spectrometry (HPLC-MS) analysis of the root extracts showed a qualitative variation of alkamides during infection. The results indicated that there is a possible relationship between secondary metabolites and tolerance against phytopathogens.

  8. Genetic variability among the brown rust resistant and susceptible genotypes of sugarcane by RAPD technique

    Science.gov (United States)

    Brown leaf rust in sugarcane is caused by Puccinia melanocephala (Syd. & P. Syd.), which is major cause of cultivar withdrawal. We attempted to analyze the RAPD diversity of two discrete phenotypic classes i.e. rust resistant (R) and rust susceptible (S) of six commercially available sugarcane elite...

  9. Influence of PEG induced drought stress on molecular and biochemical constituents and seedling growth of Egyptian barley cultivars

    Directory of Open Access Journals (Sweden)

    F.A. Hellal

    2018-06-01

    Full Text Available In order to investigate the effects of drought stress on germination components of barley cultivars, a laboratory experiment was conducted in a factorial randomized complete design with four replications. The controlled experiment included ten of Egyptian barley cultivars namely; (Giza 123, 124, 125, 126, 127, 129, 130, 134, 135 and 2000 as first factor. The second factor included 4 levels of drought stress inducer by applying 0, 5, 10 and 20% of polyethylene glycol-6000 (PEG which is equivalent to four osmotic potential levels including −0.001, −0.27, −0.54 and −1.09 MPa, respectively. The results showed that, the highest reduction was related to the drought level of 20% PEG among the barley cultivars. The best cultivars in terms of germination traits were Giza 134, Giza 127, and Giza 126 this indicate their tolerance to drought stress and Giza 130, 135, 2000 cultivars was moderately tolerance and remaining is less tolerance. The protein band 27 kDa and 78 kDa showed high intensity after stress in almost all cultivars. Those two protein bands their exciting was very clear in treated barley leaf tissue. It could be related to dehydrine and oxygen evolving enhancer protein 2 (OEE2 which involved in drought stress tolerance response. Cultivars Giza 127, 130 and 134 showed highest tolerance response under drought stress. The antioxidant enzymes PAGE pattern of Peroxidase (POX, Sodium dismutase (SOD and Ascorbate peroxidase (APX for Barley cultivars under drought stress revealed a high activities for Giza 126, 127, 134, 136 and 2000 under −0.5 MPa osmotic stress by PEG in most of their isoforms. Based on similarity coefficient values the highest values were 1.0 with 100% similarly between tolerant cultivars Giza 130 and Giza 127. Similarly between the susceptible cultivars 125 and Giza 129 was 60%.These data confirmed by the growth parameters which we ranked as tolerant to drought stress. Keywords: Barley, Drought stress, Seed germination

  10. Effect of Salt Stress on Morphological Traits of Lettuce Genotypes (Lactuca Sativa L.

    Directory of Open Access Journals (Sweden)

    maryam zare

    2017-02-01

    Full Text Available Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development by ion toxicity, ionic disturb the balance and osmotic potential. Lettuce is one of the most important vegetable crops. This plant is one of the most important leafy vegetables which is used for salad and fresh marketing, also some types of this vegetable is used in baked type. The aim of this study was to investigate the genetic diversity of lettuce genotypes undersalt stress in the hydroponic system. Materials and Methods: To assess response of lettuce seedlings to salt stress, a factorial experiment was conducted in a completely randomized design with three replications at Biotechnology Research Institute for hydroponic cultivation of Zabol. In this experiment, the effects of three salinity levels (0, 2 and 4 dS/m on morphological characteristics of 15 lettuce genotypes were evaluated. The seeds were sterilized for ten seconds in ethanol 96% and then 15% sodium hypochlorite solution for 50 seconds, then rinsed several times with distilled water, then disinfected seeds were cultured in plastic pots containing coco peat and perlite. After …days plants were transferred to hydroponic system containing Hoagland solution. Collected data were analyzed and means comparisons were made using LSD by SAS software. Results and Discussion: The results showed that salinity has a significant effect on seedling growth of lettuce genotypes (p≤0.01. significant difference between salinity levels and genotype were observed for all traits. Interaction of genotype and salinity for all the traits except root length, plant length and leaf were significant at 1%. Based on the results, the greatest root length was belong to Esfahan Varzaneh leafy lettuce and

  11. Researches Regarding the Influence of Cold Storage on the Chlorophyll Content in Lettuce

    Directory of Open Access Journals (Sweden)

    Iuliana Cretescu

    2014-05-01

    Full Text Available The aim of the present investigations was to determine the effect of the cold storage period on the content of chlorophylls in the leaves of lettuce and arugula (rucola. The research material consisted in two types of lettuce (Lactuca sativa L. var. capitata; Lactuca sativa L. var. crispa and arugula (Eruca sativa purchased from supermarkets in Timisoara. The quantitative determination of chlorophyll pigments in leaves (SPAD was made by chlorophyll meter (SPAD 502 Konica-Minolta. During the few days cold storage at a temperature of 4ºC, the content of chlorophyll in the leaf significantly decreased, compared with that in the control group. After 3 days of cold storage arugula and lettuce (Lactuca sativa var. capitata values of chlorophyll content differ statistically very significantly (p<0.001 from the values found in the control group which for lettuce (Lactuca sativa L. var. crispa differs statistically significant (p < 0.05.

  12. Effect of Root-Zone Moisture Variations on Growth of Lettuce and Pea Plants

    Science.gov (United States)

    Ilieva, Iliana; Ivanova, Tania

    2008-06-01

    Variations in substrate moisture lead to changes in water and oxygen availability to plant roots. Ground experiments were carried out in the laboratory prototype of SVET-2 Space Greenhouse to study the effect of variation of root-zone moisture conditions on growth of lettuce and pea plants. The effect of transient increase (for 1 day) and drastic increase (waterlogging for 10 days) of substrate moisture was studied with 16-day old pea and 21-day old lettuce plants respectively. Pea height and fresh biomass accumulation were not affected by transient substrate moisture increase. Net photosynthetic rate (Pn) of pea plants showed fast response to substrate moisture variation, while chlorophyll content did not change. Drastic change of substrate moisture suppressed lettuce Pn, chlorophyll biosynthesis and plant growth. These parameters slowly recovered after termination of waterlogging treatment but lettuce yield was greatly affected. The results showed that the most sensitive physiological parameter to substrate moisture variations is photosynthesis.

  13. Effect of Salt Stress on Morphological Traits of Lettuce Genotypes (Lactuca Sativa L.

    Directory of Open Access Journals (Sweden)

    maryam zare

    2017-09-01

    Full Text Available Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development by ion toxicity, ionic disturb the balance and osmotic potential. Lettuce is one of the most important vegetable crops. This plant is one of the most important leafy vegetables which is used for salad and fresh marketing, also some types of this vegetable is used in baked type. The aim of this study was to investigate the genetic diversity of lettuce genotypes undersalt stress in the hydroponic system. Materials and Methods: To assess response of lettuce seedlings to salt stress, a factorial experiment was conducted in a completely randomized design with three replications at Biotechnology Research Institute for hydroponic cultivation of Zabol. In this experiment, the effects of three salinity levels (0, 2 and 4 dS/m on morphological characteristics of 15 lettuce genotypes were evaluated. The seeds were sterilized for ten seconds in ethanol 96% and then 15% sodium hypochlorite solution for 50 seconds, then rinsed several times with distilled water, then disinfected seeds were cultured in plastic pots containing coco peat and perlite. After …days plants were transferred to hydroponic system containing Hoagland solution. Collected data were analyzed and means comparisons were made using LSD by SAS software. Results and Discussion: The results showed that salinity has a significant effect on seedling growth of lettuce genotypes (p≤0.01. significant difference between salinity levels and genotype were observed for all traits. Interaction of genotype and salinity for all the traits except root length, plant length and leaf were significant at 1%. Based on the results, the greatest root length was belong to Esfahan Varzaneh leafy lettuce and

  14. Series of Norovirus Outbreaks Caused by Consumption of Green Coral Lettuce, Denmark, April 2016

    DEFF Research Database (Denmark)

    Müller, Luise; Rasmussen, Lasse Dam; Jensen, Tenna

    2016-01-01

    In early April 2016, an unusual high number of point-source outbreaks of gastrointestinal disease were reported to occur in Denmark. Outbreaks were individually investigated. Two analytical studies were performed. Patient stool samples collected and analysed; positive stool samples were sequenced...... over the polymerase and/or capsid gene areas. Implicated lettuce heads were collected and analysed for the presence of norovirus. Foods were traced-back and traced-forward and international alert systems applied. A total of 23 linked point-source outbreaks occurred over the course of one week. Fresh...... green coral lettuce (Lollo Bionda lettuce) had been consumed in all settings. In a cohort study including 234 participants a dish containing green lettuce was associated with illness. Norovirus of Genogroup I (GI) was detected in samples from 28 patients comprising eight of the outbreaks. Sequencing...

  15. Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

    International Nuclear Information System (INIS)

    He Suyan; Li Yunfei

    2008-01-01

    The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data

  16. Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

    Science.gov (United States)

    Putri, Gitta Agnes; Sunarsih

    2018-02-01

    This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

  17. Mechanism of artemisinin phytotoxicity action: induction of reactive oxygen species and cell death in lettuce seedlings.

    Science.gov (United States)

    Yan, Zhi-Qiang; Wang, Dan-Dan; Ding, Lan; Cui, Hai-Yan; Jin, Hui; Yang, Xiao-Yan; Yang, Jian-She; Qin, Bo

    2015-03-01

    Artemisinin has been recognized as an allelochemical that inhibits growth of several plant species. However, its mode of action is not well clarified. In this study, the mechanism of artemisinin phytotoxicity on lettuce seedlings was investigated. Root and shoot elongation of lettuce seedlings were inhibited by artemisinin in a concentration-dependent manner. The compound effectively arrested cell division and caused loss of cell viability in root tips of lettuce. Overproduction of reactive oxygen species (ROS) was induced by artemisinin. Lipid peroxidation, proline overproduction and reduction of chlorophyll content in lettuce seedlings were found after treatments. These results suggested that artemisinin could induce ROS overproduction, which caused membrane lipids peroxidation and cell death, and impacted mitosis and physiological processes, resulting in growth inhibition of receptor plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Round-robin comparison of methods for the detection of human enteric viruses in lettuce

    DEFF Research Database (Denmark)

    Le Guyader, Francoise S.; Schultz, Anna Charlotte; Haugarreau, Larissa

    2004-01-01

    Five methods that detect human enteric virus contamination in lettuce were compared. To mimic multiple contaminations as observed after sewage contamination, artificial contamination was with human calicivirus and poliovirus and animal calicivirus strains at different concentrations. Nucleic acid...

  19. Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

    Energy Technology Data Exchange (ETDEWEB)

    He Suyan [School of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071 (China)], E-mail: hesuyan67829@sina.com; Li Yunfei [Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University (China)

    2008-10-15

    The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data.

  20. Effect of 5-aminolevulinic acid on yield and quality of lettuce in sunlit ...

    African Journals Online (AJOL)

    ese

    2012-07-03

    Jul 3, 2012 ... Here, we report the effects of ALA on photosynthetic rate, yield and quality of lettuce in sunlit ... Plant growth regulators (PGRs) are widely applied on crops as a means of ..... This research was made possible by financial.

  1. Seed storage effects on germination for two forage kochia cultivars

    Science.gov (United States)

    The cultivar ‘Snowstorm’ forage kochia was released by the USDA-ARS in 2012. It is a synthetic cultivar selected for stature, forage production, and adaptation to semiarid environments. Similar to the earlier released (1984) ‘Immigrant’ cultivar it can increase rangeland productivity magnitudes when...

  2. Variation between cut chrysanthemum cultivars in response to suboptimal temperature

    NARCIS (Netherlands)

    Ploeg, van der A.; Kularathne, R.J.K.N.; Carvalho, S.M.P.; Heuvelink, E.

    2007-01-01

    To breed for more energy-efficient cut chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars it is important to know the variation of the temperature response existing in modern cultivars. In a greenhouse experiment with 25 chrysanthemum cultivars, a significant variation was observed in

  3. Molecular characterization of olive cultivars grown in Iraq using ...

    African Journals Online (AJOL)

    The results of this research confirmed AFLP and SSR to be useful tools in genetic relationships among olive cultivars, in creating a molecular database for Iraqi olive cultivars, in breeding strategies and in correct cultivar identification. Keywords: Olea europaea, genetic diversity, amplified fragment length polymorphism ...

  4. Milk production potential of two ryegrass cultivars with different total ...

    African Journals Online (AJOL)

    The aim of the study was to compare a new Italian ryegrass (Lolium multiflorum) cultivar (Enhancer), bred to contain a high total non-structural carbohydrate content, with the cultivar, Dargle, in terms of dry matter (DM) production, nutritional value, carrying capacity and milk production. The ryegrass cultivars were sown (25 ...

  5. Register of New Fruit and Nut Cultivars List 46. Rambutan.

    Science.gov (United States)

    The Register of New Fruit and Nut Varieties 46 is a compilation of descriptions of new fruit and nut cultivars from around the world. In this edition, 8 newly released rambutan cultivars are described in terms of their origins, important fruit traits and yield. Of the eight described cultivars, one ...

  6. Stem rust seedling resistance genes in Ethiopian wheat cultivars ...

    African Journals Online (AJOL)

    Thirty durum wheat (19 commercial cultivars and 11 breeding lines) and 30 bread wheat (20 commercial cultivars and 10 breeding lines) were tested for gene postulation. Stem rust infection types produced on wheat cultivars and breeding lines by ten Pgt races was compared with infection types produced on 40 near ...

  7. DNA tagging of blast resistant gene(s in three Brazilian rice cultivars

    Directory of Open Access Journals (Sweden)

    S.S. Sandhu

    2003-12-01

    Full Text Available Rice blast is the most important fungal disease of rice and is caused by Pyricularia oryzae Sacc. (Telomorph Magnoporthe grisea Barr.. Seven randomly amplified polymorphic DNA (RAPD markers OPA5, OPG17, OPG18, OPG19, OPF9, OPF17 and OPF19 showed very clear polymorphism in resistant cultivar lines which differed from susceptible lines. By comparing different susceptible lines, nine DNA amplifications of seven primers (OPA5(1000, OPA5(1200, OPG17(700, OPG18(850, OPG19(500, OPG19(600, OPF9(600, OPF17(1200 and OPF19(600 were identified as dominant markers for the blast resistant gene in resistant cultivar lines. These loci facilitate the indirect scoring of blast resistant and blast susceptible genotypes. The codomine RAPDs markers will facilitate marker-assisted selection of the blast resistant gene in two blast resistant genotypes of rice (Labelle and Line 11 and will be useful in rice breeding programs.

  8. Micropropagation of peach rootstocks and cultivars.

    Science.gov (United States)

    Balla, Ildikó; Mansvelt, Lucienne

    2013-01-01

    Peach (Prunus persica (L.) Batsch) is one of the most popular stone fruits, commercially produced largely in Mediterranean and, to a lesser extent, in continental climatic conditions. Several breeding programs with different aims release annually large numbers of new cultivars. Micropropagation offers a suitable method to provide the growers of sufficient quantities of rootstocks, as well as of pathogen-free planting material of old and new cultivars.An effective four-step micropropagation procedure for cultivar and rootstock production is described here, based on the use of modified MS and WPM media. The health status of the initial shoot tips is very important, also because the growth and proliferation rate of shoot cultures from virus-infected clones are generally very poor. Proliferation and elongation phases depend on the major macro-elements, as well as the content and ratio of plant growth regulators. It is important to grow the cultures at 22°C, as hyperhydricity may develop at higher temperatures. Although sucrose is the most common carbon source used during proliferation and rooting, for some peach cultivars and rootstocks the replacement of sucrose (10 g/L) with glucose (20 g/L) in the rooting medium improves the rooting and survival rates of plants in the acclimatization phase. The rooting rate of the rootstock "Cadaman" is improved with the chelated form of iron FeEDDHA at 150 mg/L. Rooted plants are acclimatized in greenhouse under high humidity conditions.

  9. Growth and development in Achimenes cultivars

    NARCIS (Netherlands)

    Vlahos, J.C.

    1991-01-01

    Achimenes is a herbaceous perennial of the Gesneriaceae family. Its origin is Central and South America. It has been cultivated as a pot plant since the Victorian era. Extensive hybridization has produced many attractive cultivars which have been Introduced in

  10. Transformation of multiple soybean cultivars by infecting ...

    African Journals Online (AJOL)

    Transformation of multiple soybean cultivars by infecting cotyledonary-node with Agrobacterium tumefaciens. ... In our study, the combination of Nannong88-1 with EHA105 is the optimum selection for explant and bacterial inoculum in soybean transformation, which could be applied in future functional study of soybean ...

  11. Unfolding the potential of wheat cultivar mixtures

    DEFF Research Database (Denmark)

    Borg, J.; Kiær, Lars Pødenphant; Lecarpentier, C.

    2018-01-01

    and they are not encouraged by advisory services. Based on the methodology developed by Kiær et al. (2009), we achieved a meta-analysis of cultivar mixtures in wheat. Among the 120 publications dedicated to wheat, we selected 32 studies to analyze various factors that may condition the success or failure of wheat mixtures...

  12. (EAHB-AAA) cultivars to drought stress

    African Journals Online (AJOL)

    Banana (Musa spp.) yields are estimated at 5-30 t ha-1yr-1, lower than the potential 60 t ha-1yr-1, with the cause being drought stress. Much evidence among stakeholders shows little understanding about banana cultivar sensitivity, escape and avoidance mechanisms to drought due to un-attempted measures of retaining ...

  13. Bloemverdroging: Cultivars met vroege bloemaanleg koeler bewaren

    NARCIS (Netherlands)

    Dam, van M.F.N.

    2013-01-01

    Uitval in de tulpenbroeierij door bloemverdroging kwam de afgelopen jaren veel meer voor dan daarvoor. Reden voor PPO om na te gaan wat hiervan de oorzaak zou kunnen zijn. In dit artikel legt onderzoeker Martin van Dam uit dat vooral in warme lentes bij vroege cultivars de kans op bloemverdroging

  14. Comparison of proteome response to saline and zinc stress in lettuce

    OpenAIRE

    Lucini, Luigi; Bernardo, Letizia

    2015-01-01

    Zinc salts occurring in soils can exert an osmotic stress toward plants. However, being zinc a heavy metal, some more specific effects on plant metabolisms can be forecast. In this work, lettuce has been used as a model to investigate salt and zinc stresses at proteome level through a shotgun tandem MS proteomic approach. The effect of zinc stress in lettuce, in comparison with NaCl stress, was evaluated to dissect between osmotic/oxidative stress related effects, from those changes specifica...

  15. The effect of growth conditions on flavonols and anthocyanins accumulation in green and red lettuce

    OpenAIRE

    Klaudia BRÜCKOVÁ; Oksana SYTAR; Marek ŢIVČÁK; Marian BRESTIC; Aleš LEBEDA

    2016-01-01

    The aim of the study was to investigate the effect of different growth conditions on anthocyanins and flavonols accumulation in leaves of green and red loose leaf lettuce (Lactuca sativa var. crispa). Lettuce plants were grown in three types of conditions, in greenhouse (I. variant), behind clear glass in field (II. variant) and in open field conditions (III. variant). Estimation of anthocyanins and flavonols content was done by non-destructive measurements with optical fluorescence sensor Mu...

  16. Antioxidant capacity and contents of phenols, ascorbic acid, β-carotene and lycopene in lettuce

    OpenAIRE

    Zdravković Jasmina M.; Aćamović-Đoković Gordana S.; Mladenović Jelena D.; Pavlović Radoš M.; Zdravković Milan S.

    2014-01-01

    The antioxidant activity of three lettuce varieties (Lactuca sativa L.) Emerald, Vera and Neva, cultivated in two kinds of protected spaces, a glasshouse and a plastic greenhouse, under controlled conditions, was determined. The content of antioxidant compounds: total phenols, flavonoids, L-ascorbic acid, ß-carotene and lycopene, were determined in ethanolic extracts of the lettuce with spectrophotometric methods. The largest content of total phenols (78.98...

  17. Effects of composted tobacco waste and farmyard manure on some soil physical properties and lettuce yield

    OpenAIRE

    Çerçioğlu, Melis; Okur, Bülent; Delibacak, Sezai; Ongun, Ali Rıza

    2008-01-01

    This research was held in Agriculture Faculty of Ege University Menemen Investigation and Practise Farmyard. Tobacco waste gathered from cigarette industry were composted and applied to the soil together with farmyard manure. lettuce (Lactuca sativa L. var. capitata) was grown as test plant. No mineral fertilizers or pestisides were applied. The effects of composted tobacco wastes and farmyard manures on soil physical properties and lettuce yield were investigated. All application...

  18. The economics of managing Verticillium wilt, an imported disease in California lettuce

    OpenAIRE

    Carroll, Christine L; Carter, Colin A; Goodhue, Rachael E; Lin Lawell, C.-Y. Cynthia; Subbarao, Krishna V

    2017-01-01

    Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take ...

  19. Effects of long-term low atmospheric pressure on gas exchange and growth of lettuce

    Science.gov (United States)

    Tang, Yongkang; Guo, Shuangsheng; Dong, Wenping; Qin, Lifeng; Ai, Weidang; Lin, Shan

    2010-09-01

    The objectives of this research were to determine photosynthesis, evapotranspiration and growth of lettuce at long-term low atmospheric pressure. Lettuce ( Lactuca sativa L . cv. Youmaicai) plants were grown at 40 kPa total pressure (8.4 kPa p) or 101 kPa total pressure (20.9 kPa p) from seed to harvest for 35 days. Germination rate of lettuce seeds decreased by 7.6% at low pressure, although this was not significant. There was no significant difference in crop photosynthetic rate between hypobaria and ambient pressure during the 35-day study. The crop evapotranspiration rate was significantly lower at low pressure than that at ambient pressure from 20 to 30 days after planting (DAP), but it had no significant difference before 20 DAP or after 30 DAP. The growth cycle of lettuce plants at low pressure was delayed. At low pressure, lettuce leaves were curly at the seedling stage and this disappeared gradually as the plants grew. Ambient lettuce plants were yellow and had an epinastic growth at harvest. The shoot height, leaf number, leaf length and shoot/root ratio were lower at low pressure than those at ambient pressure, while leaf area and root growth increased. Total biomass of lettuce plants grown at two pressures had no significant difference. Ethylene production at low pressure decreased significantly by 38.8% compared with ambient pressure. There was no significant difference in microelements, nutritional phytochemicals and nitrate concentrations at the two treatments. This research shows that lettuce can be grown at long-term low pressure (40 kPa) without significant adverse effects on seed germination, gas exchange and plant growth. Furthermore, ethylene release was reduced in hypobaria.

  20. The Comparison of Ammonium or Nitrate-Grown Lettuce and Spinach in a Hydroponic System

    OpenAIRE

    H. R. Roosta

    2010-01-01

    Most plant species are sensitive to high ammonium concentrations. In this experiment the sensitivity of lettuce and spinach to ammonium was investigated. In a factorial experiment with framework of a completely randomized design with two factors, nitrogen form (ammonium and nitrate) and plant species (lettuce and spinach), and three replications seeds were germinated in a mixture of perlite, sand and clay in soil-maid pots. After two weeks, the seedlings at two true-leaf stage were then trans...

  1. Diminished UV-absorbing nets reduce the Spreads and population density of Macrosiphum euphorbiae in lettuce.

    OpenAIRE

    Legarrea, S.; Díaz, B. M.; Plaza, M.; Barrios, L.; Morales, Ignacio; Viñuela Sandoval, Elisa; Fereres Castiel, Alberto

    2012-01-01

    UV-absorbing covers reduce the incidence of injurious insect pests and viruses in protected crops. In the present study, the effect of a UV-absorbing net (Bionet) on the spatio-temporal dynamics of the potato aphid on lettuce plants was evaluated. A field experiment was conducted during three seasons in two identical tunnels divided in four plots. A set of lettuce plants were artificially infested with Macrosiphum euphorbiae adults and the population was estimated by counting aphids on ev...

  2. Oxygenated phosphine fumigation for control of Nasonovia ribisnigri (Homoptera: Aphididae) on harvested lettuce.

    Science.gov (United States)

    Liu, Yong-Biao

    2012-06-01

    Low temperature regular phosphine fumigations under the normal oxygen level and oxygenated phosphine fumigations under superatmospheric oxygen levels were compared for efficacy against the aphid, Nasonovia ribisnigri (Mosley), and effects on postharvest quality of romaine and head lettuce. Low temperature regular phosphine fumigation was effective against the aphid. However, a 3 d treatment with high phosphine concentrations of > or = 2,000 ppm was needed for complete control of the aphid. Oxygen greatly increased phosphine toxicity and significantly reduced both treatment time and phosphine concentration for control of N. ribisnigri. At 1,000 ppm phosphine, 72 h regular fumigations at 6 degrees C did not achieve 100% mortality of the aphid. The 1,000 ppm phosphine fumigation under 60% O2 killed all aphids in 30 h. Both a 72 h regular fumigation with 2,200 ppm phosphine and a 48 h oxygenated fumigation with 1,000 ppm phosphine under 60% O2 were tested on romaine and head lettuce at 3 degrees C. Both treatments achieved complete control of N. ribisnigri. However, the 72 h regular fumigation resulted in significantly higher percentages of lettuce with injuries and significantly lower lettuce internal quality scores than the 48 h oxygenated phosphine fumigation. Although the oxygenated phosphine fumigation also caused injuries to some treated lettuce, lettuce quality remained very good and the treatment is not expected to have a significant impact on marketability of the lettuce. This study demonstrated that oxygenated phosphine fumigation was more effective and less phytotoxic for controlling N. ribisnigri on harvested lettuce than regular phosphine fumigation and is promising for practical use.

  3. High-Resolution Analysis of the Efficiency, Heritability, and Editing Outcomes of CRISPR/Cas9-Induced Modifications of NCED4 in Lettuce (Lactuca sativa).

    Science.gov (United States)

    Bertier, Lien D; Ron, Mily; Huo, Heqiang; Bradford, Kent J; Britt, Anne B; Michelmore, Richard W

    2018-05-04

    CRISPR/Cas9 is a transformative tool for making targeted genetic alterations. In plants, high mutation efficiencies have been reported in primary transformants. However, many of the mutations analyzed were somatic and therefore not heritable. To provide more insights into the efficiency of creating stable homozygous mutants using CRISPR/Cas9, we targeted LsNCED4 ( 9-cis-EPOXYCAROTENOID DIOXYGENASE4) , a gene conditioning thermoinhibition of seed germination in lettuce. Three constructs, each capable of expressing Cas9 and a single gRNA targeting different sites in LsNCED4 , were stably transformed into lettuce (Lactuca sativa) cvs. Salinas and Cobham Green. Analysis of 47 primary transformants (T 1 ) and 368 T 2 plants by deep amplicon sequencing revealed that 57% of T 1 plants contained events at the target site: 28% of plants had germline mutations in one allele indicative of an early editing event (mono-allelic), 8% of plants had germline mutations in both alleles indicative of two early editing events (bi-allelic), and the remaining 21% of plants had multiple low frequency mutations indicative of late events (chimeric plants). Editing efficiency was similar in both genotypes, while the different gRNAs varied in efficiency. Amplicon sequencing of 20 T 1 and more than 100 T 2 plants for each of the three gRNAs showed that repair outcomes were not random, but reproducible and characteristic for each gRNA. Knockouts of NCED4 resulted in large increases in the maximum temperature for seed germination, with seeds of both cultivars capable of germinating >70% at 37°. Knockouts of NCED4 provide a whole-plant selectable phenotype that has minimal pleiotropic consequences. Targeting NCED4 in a co-editing strategy could therefore be used to enrich for germline-edited events simply by germinating seeds at high temperature. Copyright © 2018 Bertier et al.

  4. Evaluation of three biostimulants in lettuce under parcel conditions

    Directory of Open Access Journals (Sweden)

    María Caridad Jiménez Arteaga

    2016-02-01

    Full Text Available The work was developed in the parcel Ñico López. The valued cultivation was the lettuce variety Black simpson, with the objective of evaluating the goods of three (3 bioestimulantes (Biobras 16, Biobras plus and Quitosana, about the yield and quality of the crop. The biostimulants was applied, to three stonemasons (one for biostimulant to the six days after transplant (DDT and three parcel to the seven DDT, leaving one stonemasons that as control, for an total seven (7 treatments. The main components of yield were measured and some components of the quality of the plant were determined in the Soils Province Laboratory The data were processed by the statistical package of the Statitic version 8 on Windows. One could observe that the three biostimulants has an effect positive on the mass and quality of the studied crop.

  5. Changes during imbition of irradiated dry seeds of lettuce

    International Nuclear Information System (INIS)

    Smith, M.T.

    1981-01-01

    Since ionizing radiation has been shown to produce free-radicals in dry seeds, effect peroxidation of lipids in model systems, and cause changes in membrane permeability, it was decided to subject dry seeds of lettuce to gamma irradiation to determine whether the cytological changes which occurred on subsequent imbition are similar in any way to those occurring during natural ageing in dry storage. Seeds of 3% moisture content were radiated with gamma rays from a Cobalt 60 source at doses between 3,4 kGy and 23,8 kGy and the root tips prepared for TEM after 5 and 12 hours imbition. The cytological changes which occurred are shortly discussed

  6. Use of Propolis in the Sanitization of Lettuce

    Directory of Open Access Journals (Sweden)

    Xesús Feás

    2014-07-01

    Full Text Available The present study aimed to determine the effectiveness of propolis in reducing the microbial load in ready-to-eat (RTE and fresh whole head (FWH lettuces (Lactuca sativa L. type Batavia. Two sanitizing solutions were employed: sodium hypochlorite (SH and propolis (PS, during 15 and 30 min. Tap water (TW was used as a control. Regarding the mean reduction on aerobic mesophiles, psychrotrophic and fecal coliforms, the SH and PS treatments showed the same pattern of variation. In all cases, PS was slightly more effective in the microbiological reduction in comparison with commercial SH. Reductions between two and three log cycles were obtained with PS on aerobic mesophiles and psychrotrophic counts. The information obtained in the present study can be used to evaluate the potential use of propolis as product for sanitizing other vegetables and for developing other food preservation technologies, with impact on human health.

  7. Changes during imbition of irradiated dry seeds of lettuce

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M T [Natal Univ., Durban (South Africa). Dept. of Biological Sciences

    1981-01-01

    Since ionizing radiation has been shown to produce free-radicals in dry seeds, effect peroxidation of lipids in model systems, and cause changes in membrane permeability, it was decided to subject dry seeds of lettuce to gamma irradiation to determine whether the cytological changes which occurred on subsequent imbition are similar in any way to those occurring during natural ageing in dry storage. Seeds of 3% moisture content were radiated with gamma rays from a Cobalt 60 source at doses between 3,4 kGy and 23,8 kGy and the root tips prepared for TEM after 5 and 12 hours imbition. The cytological changes which occurred are shortly discussed.

  8. Radiotracer studies of maneb residues in lettuce plants

    International Nuclear Information System (INIS)

    Sennaoui, Z.; Meguenni, H.; Bennaceur, M.

    1990-11-01

    Lettuce plants have received different treatments of 14C-maneb at variable time. A cleaning is made to determine the foliar surface residues. The analysis of CS2 showed relatively important amount especially for lots which have received 4 treatments (10,3ppm and 6,49ppm). The amounts found after combustion have showed increasing amounts, proportionally to the number of treatments. The analysis of ETU revealed a presence only for lots which have received several treatments (3 and 4). The analysis by TLC showed many metabolites. Two of them have been identified (ETU, EU). Interfoliar migration of 14C product occurred between treated leaves and untreated leaves of the same plant

  9. High-level transient expression of recombinant protein in lettuce.

    Science.gov (United States)

    Joh, Lawrence D; Wroblewski, Tadeusz; Ewing, Nicholas N; VanderGheynst, Jean S

    2005-09-30

    Transient expression following agroinfiltration of plant tissue was investigated as a system for producing recombinant protein. As a model system, Agrobacterium tumefaciens containing the beta-glucuronidase (GUS) gene was vacuum infiltrated into lettuce leaf disks. Infiltration with a suspension of 10(9) colony forming units/mL followed by incubation for 72 h at 22 degrees C in continuous darkness produced a maximum of 0.16% GUS protein based on dry tissue or 1.1% GUS protein based on total soluble protein. This compares favorably to expression levels for commercially manufactured GUS protein from transgenic corn seeds. A. tumefaciens culture medium pH between 5.6 and 7.0 and surfactant concentrations lettuce to produce GUS protein more rapidly, but final levels did not exceed the GUS production in leaves incubated in continuous darkness after 72 h at 22 degrees C. The kinetics of GUS expression during incubation in continuous light and dark were represented well using a logistic model, with rate constants of 0.30 and 0.29/h, respectively. To semi-quantitatively measure the GUS expression in large numbers of leaf disks, a photometric enhancement of the standard histochemical staining method was developed. A linear relationship with an R2 value of 0.90 was determined between log10 (% leaf darkness) versus log10 (GUS activity). Although variability in expression level was observed, agroinfiltration appears to be a promising technology that could potentially be scaled up to produce high-value recombinant proteins in planta. Copyright 2005 Wiley Periodicals, Inc

  10. Purification and Characterization of Polyphenol Oxidase, Peroxidase and Lipoxygenase from Freshly Cut Lettuce (L. sativa

    Directory of Open Access Journals (Sweden)

    Vural Gökmen

    2011-01-01

    Full Text Available Enzymatic reactions taking place in minimally processed vegetables are considered as a major problem, because they adversely affect sensorial and nutritional quality. Polyphenol oxidase (PPO, peroxidase (POD and lipoxygenase (LOX from lettuce were purified on a column packed with positively charged diethylaminoethyl (DEAE cellulose by applying pH gradient elution from pH=4.0 to 9.0. The main purified fractions (PPO1 and PPO4, POD1 and POD2, LOX1 and LOX2 were characterized for enzyme concentration-reaction rate relationship, thermal stability, pH activity and kinetic parameters. Kinetic properties of each isoform were considerably different. Cysteine was found as the most effective inhibitor of both fractions of PPO. Kinetic parameters of lettuce POD were presented using guaiacol at various H2O2 concentrations. β-carotene directly influences lettuce LOX in the reaction medium available for the catalytic conversion of linoleic acid into hydroperoxides. Ascorbic and oxalic acids appear as effective PPO inhibitors, protecting phenolic compounds against oxidation in lettuce. Understanding the characteristics of deteriorative enzymes becomes important to maintain suitable conditions for fresh-like quality of lettuce. The results can be useful to keep the nutritional quality of minimally processed lettuce during shelf-life.

  11. Determination of Profenofos Pesticidal Residue in Lettuce (Lactuca sativa L. by Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Yohannes Alen

    2015-05-01

    Full Text Available The determination of profenofos pesticidal residue in the lettuce (Lactuca sativa L. by using gas chromatography using flame photometric detector (FPD had been investigated. The lettuce was collected from Padang Luar area, Agam distric, West Sumatera. Sample for determination of profenofos residue divided into three groups: unwashed (A, washed with water (B, and washed with detergent (C. Maceration with sonication was used for the extraction using ethylacetateas a solvent. The results showed that profenofos pesticide residue in sample A, B and C were 0.204, 0.080 and 0.061 ppm, respectively. These profenofos pesticidal residue are over than the Maximum Residue Limits (MRL that established by The Japan Food Chemical Research Foundation (0.05 ppm even though World Health Organization (WHO has not established Maximum Residue Limits (MRL profenofos on lettuce. Based on the statistical analysis one-way method (Anova using SPSS 20.0 showed that there was a significant concentrations difference between lettuce A from lettuce B and lettuce C with p < 0.05.

  12. Uptake and Accumulation of Pharmaceuticals in Lettuce Under Surface and Overhead Irrigations

    Science.gov (United States)

    Bhalsod, G.; Chuang, Y. H.; Jeon, S.; Gui, W.; Li, H.; Guber, A.; Zhang, W.

    2015-12-01

    Pharmaceuticals and personal care products are being widely detected in wastewater and surface waters. As fresh water becomes scarcer, interests in using reclaimed water for crop irrigation is intensified. Since reclaimed waters often carry trace levels of pharmaceuticals, accumulation of pharmaceuticals in food crops could increase the risk of human exposure. This study aims to investigate uptake and accumulations of pharmaceuticals in greenhouse-grown lettuce under contrasting irrigation practices (i.e., overhead and surface irrigations). Lettuce was irrigated with water spiked with 11 commonly used pharmaceuticals (acetaminophen, caffeine, carbamazepine, sulfadiazine, sulfamethoxazole, carbadox, trimethoprim, lincomycin hydrochloride, oxytetracycline hydrochloride, monensin sodium, and tylosin). Weekly sampling of lettuce roots, shoots, and soils were continued for 5 weeks, and the samples were freeze dried, extracted for pharmaceuticals and analyzed by LC-MS/MS. Preliminary results indicate that higher concentrations of pharmaceuticals were found in overhead irrigated lettuce compared to surface irrigated lettuce. For carbamezapine, sulfadiazine, trimethoprim, oxytetracycline, and monensin sodium, their concentrations generally increased in lettuce shoots in the overhead treatment over time. However, acetaminophen was found at higher concentrations in both shoots and roots, indicating that acetaminophen can be easily transported in the plant system. This study provides insight on developing better strategies for using reclaimed water for crop irrigations, while minimizing the potential risks of pharmaceutical contamination of vegetables.

  13. Arsenic uptake by lettuce from As-contaminated soil remediated with Pteris vittata and organic amendment.

    Science.gov (United States)

    de Oliveira, Letuzia M; Suchismita, Das; Gress, Julia; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

    2017-06-01

    Leaching of inorganic arsenic (As) from chromated copper arsenate (CCA)-treated wood may elevate soil As levels. Thus, an environmental concern arises regarding As accumulation in vegetables grown in these soils. In this study, a greenhouse experiment was conducted to investigate the ability of As-hyperaccumulator P. vittata and organic amendments in reducing As uptake by lettuce (Lactuca sativa) from a soil contaminated from CCA-treated wood (63.9 mg kg -1 As). P. vittata was grown for 150 d in a CCA-contaminated soil amended with biochar, activated carbon or coffee grounds at 1%, followed by lettuce for another 55 d. After harvest, plant biomass and As concentrations in plant and soil were determined. The presence of P. vittata reduced As content in lettuce by 21% from 27.3 to 21.5 mg kg -1 while amendment further reduced As in lettuce by 5.6-18%, with activated C being most effective. Our data showed that both P. vittata and organic amendments were effective in reducing As concentration in lettuce. Though no health-based standard for As in vegetables exists in USA, care should be taken when growing lettuce in contaminated soils. Our data showed that application of organic amendments with P. vittata reduced As hazards in CCA-contaminated soils. Published by Elsevier Ltd.

  14. Ultralow oxygen treatment for postharvest control of Nasonovia ribisnigri (Homoptera: Aphididae) on iceberg lettuce.

    Science.gov (United States)

    Liu, Yong-Biao

    2005-12-01

    The aphid Nasonovia ribisnigri (Mosley) is a common pest of lettuce in the United States. It hinders export of U.S. lettuce to the overseas market such as Japan where it is a quarantined pest. Ultralow oxygen treatments were studied for control of the insect on iceberg lettuce. Small-scale ultralow oxygen treatments in plastic jars were conducted at 1, 5, and 10 degrees C for different durations to determine effective treatment against nymphs and alates of N. ribisnigri. At oxygen levels of 0.015-0.025%, N. ribisnigri can be controlled in 3 d at 1 degrees C, 2 d at 5 degrees C, and 1 d at 10 degrees C. Large-scale ultralow oxygen treatments were conducted in bulk container treatment chambers with commercial iceberg lettuce heads for 2 d at 6 degrees C with oxygen levels of 0.015 and 0.025% and for 3 d at 3 degrees C with oxygen level of 0.015%. All treatments achieved complete control of N. ribisnigri. No negative impact on lettuce quality was detected after 2 wk of posttreatment storage. Therefore, the selected treatments have potential to be commercially developed for postharvest control of N. ribisnigri on iceberg lettuce.

  15. Bacterial diversity and community structure in lettuce soil are shifted by cultivation time

    Science.gov (United States)

    Liu, Yiqian; Chang, Qing; Guo, Xu; Yi, Xinxin

    2017-08-01

    Compared with cereal production, vegetable production usually requires a greater degree of management and larger input of nutrients and irrigation, but these systems are not sustainable in the long term. This study aimed to what extent lettuce determine the bacterial community composition in the soil, during lettuce cultivation, pesticides and fertilizers were not apply to soil. Soil samples were collected from depths of 0-20cm and 20-40cm. A highthroughput sequencing approach was employed to investigate bacterial communities in lettuce-cultivated soil samples in a time-dependent manner. The dominant bacteria in the lettuce soil samples were mainly Proteobacteria, Actinobacteria, Chloroflexi, Nitrospirae, Firmicutes, Acidobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Gemmatimo nadetes, Cyanobacteria. Proteobacteria was the most abundant phylum in the 6 soil samples. The relative abundance of Acidobacteria, Firmicutes, Bacteroidetes, Verrucomicrobia and Cyanobacteria decreased through time of lettuce cultivation, but the relative abundance of Proteobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi, Planctomycetes and Nitrospirae increased over time. In the 0-20cm depth group and the 20-40cm depth soil, a similar pattern was observed that the percentage number of only shared OTUs between the early and late stage was lower than that between the early and middle stage soil, the result showed that lettuce growth can affect structure of soil bacterial communities.

  16. Variations in cadmium accumulation among Chinese cabbage cultivars and screening for Cd-safe cultivars

    International Nuclear Information System (INIS)

    Liu Weitao; Zhou Qixing; An Jing; Sun Yuebing; Liu Rui

    2010-01-01

    Variations in cadmium accumulation and translocation among 40 Chinese cabbage cultivars were studied to identify and screen out Cd-safe cultivars (CSCs), i.e. cultivars with low enough accumulation of Cd in their edible parts even when grown in contaminated soils. It was observed in the pot-culture experiment that there was a significant difference (p < 0.05) in shoot Cd concentrations under three Cd treatments (1.0, 2.5 and 5.0 mg/kg), with corresponding average values 0.88, 4.45 and 7.76 mg/kg, respectively. Shoot Cd concentrations in 16 cabbage cultivars were lower than 0.50 mg/kg. The translocation factors (TFs) and the extraction factors (EFs) in five cabbage cultivars were lower than 1.0 in the pot-culture experiment. The field-culture experiment further validated that New Beijing 3 and Fengyuanxin 3 could be considered as CSCs. In particular, the two cultivars can be cultivated in low to moderate Cd-contaminated soils (Cd concentration <1.25 mg/kg) to minimize the Cd accumulation in the food.

  17. CULTIVAR RELEASE - BRSMG União: common bean cultivar with jalo grain for the state of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Magno Antonio Patto Ramalho

    2012-12-01

    Full Text Available The bean cultivar BRSMG União as a new option of a bean cultivar with jalo grains for the state of Minas Gerais. The cultivar BRSMG União had an average grain yield of 9.8% above the mean of the controls (Jalo EEP 558 and BRS Radiante and was resistant to powdery-mildew.

  18. RADISH CULTIVARS BRED AT VNIISSOK AND THEIR USE

    Directory of Open Access Journals (Sweden)

    M. I. Fedorova

    2016-01-01

    Full Text Available On the base of comparative assessment and average data estimation from 2010 to 2015, the characteristics of 11 cultivars bred at VNIISSOK were described regarding yield capacity and its components, variation, interdependencies at two sowing terms winter,spring time, direction of selection and cultivar uses at cultivar maintaining breeding program. Cultivar 'Koroleva Margo' is rather used in breeding program for yield capacity and taste qualities. Cultivar 'Sonata' is a source of such features as early maturity, valuable biochemical content and low nitrate accumulation. Cultivar 'Sofit' is known to bear early maturity and simultaneous seed maturation. 'Ariya' is a source of cylindrical root shape and early maturation. Cultivar 'Teplichnyi Gribovskyi' is used in breeding program for early maturation and simultaneous seed maturation. Cultivar 'Feya' bearsresistance to bolting and valuable biochemical substances. Cultivar 'Variant' has such features as root density, ability to grow under low lighting, short-term storability.  Purple-red with white tips is a newmade cultivar 'Mavr' suitable for breeding program for valuable biochemical content, unusual root color, also bearing male sterile forms (MS for heterosis hybrid breeding. Out of all cultivars regarded, 'Mokhovskiy' is only a genetic source to breed radish forms with edible leaves. The positive weak dependence was revealed between cultivar biochemical characteristics, root weight, dry matter  content, and nitrate content; whereas the positive middle dependence is revealed with sugar contents and negative dependence with ascorbic acid content. According to  iochemical characteristics, the best cultivar population as 'Ariya', 'Sonata' (ascorbic acid; Mavr, Sonata, Variant (dry matter, sugars have been chosen. Cultivars 'Koroleva Margo', Pheya, Sonata, Sophit, Mokhovskiy are the initial breeding accessions for selection of new cultivar population, MS and MF lines needed for heterosis.

  19. Phenylalanine ammonia-lyase (pal) and peroxidase activity in brown rust infected tissues of pakistani wheat cultivars

    International Nuclear Information System (INIS)

    Riaz, A.; Tahir, M.I.

    2014-01-01

    Besides other factors resistance and susceptibility is the outcome of biochemical processes such as activities of defense-related enzymes. So in this study, Phenylalanine ammonia-lyase (PAL) and Peroxidase activity of resistant (Inqilab-91) and susceptible (Kirin-95) wheat cultivars were determined through spectrophotometer to address the biochemical aspect related to the disease after 8 hours, 24 hours, 48 hours and 72 hours of leaf rust inoculation. The results have shown that these enzymes were present in both the resistant and susceptible cultivars but the activity was more pronounced in the resistant one. The effect of PAL and peroxidase activity was also investigated among inoculated and uninoculated plants within the same cultivar. The activity of both PAL and peroxidase were more significant in inoculated ones. The results have shown that the after 72 hours of inoculation Inqilab-91 had more PAL activity i.e., 5.47 IU/ml/min than in Kirin-95 i.e., 2.08 IU/ml/min at 270 nm. While peroxidase activity in Inqilab-91 was 6.41 IU/ml/min and in Kirin-95, 3.66 IU/ml/min after 72 hours of inoculation, observed under 470 nm wavelength. Increase in one's activity increases the other enzyme's activity. The activity was more prominent after 72 hours of infection as pathogen had successfully established itself in the host plant tissue. The activities of these enzymes act as plants active defense mechanism against the attack of pathogen. (author)

  20. Lytic bacteriophages reduce Escherichia coli O157: H7 on fresh cut lettuce introduced through cross-contamination.

    Science.gov (United States)

    Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

    2013-01-01

    The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm 2 ) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm 2 ). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm 2 ) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm 2 ) on day 0 compared with control treatments (4.10 log CFU/cm 2 ). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce.

  1. Differential response of banana cultivars to F. oxysporum f. sp. cubense infection for Chitinase activity

    International Nuclear Information System (INIS)

    Morpurgo, R.; Duren, M. Van; Grasso, G.; Afza, R.

    1997-01-01

    Six banana clones with varying levels of resistance were inoculated with conidial suspension of races 1 and 4 of Fusarium oxysporum f. sp. cubense. Chitanase activity in the corm and root tissues was monitored before and after infection to relate with the field resistance or susceptibility of banana cultivars. Resistant clones showed high constitutive chitinase activity in roots and a rapid response to infection. The results suggest that chitinase could be considered as part of a complex mechanism leading to disease resistance. (author). 5 refs, 8 figs

  2. Effects of Botrytis and ozone on bracts and flowers of poinsettia cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Manning, W.J.; Feder, W.A.; Perkins, I.

    1972-09-01

    Variability, ranging from complete resistance to extensive susceptibility, was observed when flowers and bracts of 14 cultivars of poinsettia were inoculated with spores of Botrytis cinerea. Flowers and bracts were not visibly injured by exposure to ozone levels up to 45 pphm. Ozone did not have significant fungicidal effects, as measured by visual disease incidence following incubation, when inoculated flowers and bracts were exposed to ozone at 15, 25, 35, and 45 pphm ozone for 4 hr prior to incubation. 8 references, 1 table.

  3. Differential response of banana cultivars to F. oxysporum f. sp. cubense infection for Chitinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Morpurgo, R; Duren, M Van; Grasso, G; Afza, R [Agriculture and Biotechnology Laboratory, International Atomic Energy Agency, Seibersdorf (Austria)

    1997-07-01

    Six banana clones with varying levels of resistance were inoculated with conidial suspension of races 1 and 4 of Fusarium oxysporum f. sp. cubense. Chitanase activity in the corm and root tissues was monitored before and after infection to relate with the field resistance or susceptibility of banana cultivars. Resistant clones showed high constitutive chitinase activity in roots and a rapid response to infection. The results suggest that chitinase could be considered as part of a complex mechanism leading to disease resistance. (author). 5 refs, 8 figs.

  4. Microbial risk in wastewater irrigated lettuce: comparing Escherichia coli contamination from an experimental site with a laboratory approach.

    Science.gov (United States)

    Makkaew, P; Miller, M; Fallowfield, H J; Cromar, N J

    This study assessed the contamination of Escherichia coli, in lettuce grown with treated domestic wastewater in four different irrigation configurations: open spray, spray under plastic sheet cover, open drip and drip under plastic sheet cover. Samples of lettuce from each irrigation configuration and irrigating wastewater were collected during the growing season. No E. coli was detected in lettuce from drip irrigated beds. All lettuce samples from spray beds were positive for E. coli, however, no statistical difference (p > 0.05) was detected between lettuces grown in open spray or covered spray beds. The results from the field experiment were also compared to a laboratory experiment which used submersion of lettuce in wastewater of known E. coli concentration as a surrogate method to assess contamination following irrigation. The microbial quality of spray bed lettuces was not significantly different from submersed lettuce when irrigated with wastewater containing 1,299.7 E. coli MPN/100 mL (p > 0.05). This study is significant since it is the first to validate that the microbial contamination of lettuce irrigated with wastewater in the field is comparable with a laboratory technique frequently applied in the quantitative microbial risk assessment of the consumption of wastewater irrigated salad crops.

  5. Phosphate effect on the content of selected elements in a lettuce variety grown at a contaminated soil

    International Nuclear Information System (INIS)

    Armelin, M.J.A.; Saiki, M.; Maihara, V.A.; Moreira, E.G.; Trevizam, A.R.; Muraoka, T.; Silva, M.L.S.

    2014-01-01

    The purpose of this study was to evaluate the efficiency of superphosphate fertilizer in remediating a contaminated soil with potentially toxic elements. For this, different phosphorus doses were used in a number of lettuce plants. The element concentrations determined in their leaves were compared with those found in control lettuce plants. Instrumental neutron activation analysis was the analytical technique used to determine element concentration in lettuce leave samples. The application of 250 mg kg -1 of P was the most effective treatment to reduce the concentrations of Br, Ca, Cd, Cl, Co, Cr, Fe, K, Mg, Mn, Sb and Zn in lettuce leaves. (author)

  6. Antineurodegenerative effect of phenolic extracts and caffeic acid derivatives in romaine lettuce on neuron-like PC-12 cells.

    Science.gov (United States)

    Im, Sung-Eun; Yoon, Hyungeun; Nam, Tae-Gyu; Heo, Ho Jin; Lee, Chang Yong; Kim, Dae-Ok

    2010-08-01

    In recent decades, romaine lettuce has been one of the fastest growing vegetables with respect to its consumption and production. An understanding is needed of the effect of major phenolic phytochemicals from romaine lettuce on biological protection for neuron-like PC-12 cells. Phenolics in fresh romaine lettuce were extracted, and then its total phenolics and total antioxidant capacity were measured spectrophotometrically. Neuroprotective effects of phenolic extract of romaine lettuce and its pure caffeic acid derivatives (caffeic, chicoric, chlorogenic, and isochlorogenic acids) in PC-12 cells were evaluated using two different in vitro methods: lactate dehydrogenase release and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assays. Total phenolics and total antioxidant capacity of 100 g of fresh romaine lettuce averaged 22.7 mg of gallic acid equivalents and 31.0 mg of vitamin C equivalents, respectively. The phenolic extract of romaine lettuce protected PC-12 cells against oxidative stress caused by H(2)O(2) in a dose-dependent manner. Isochlorogenic acid, one of the phenolics in romaine lettuce, showed stronger neuroprotection than the other three caffeic acid derivatives also found in the lettuce. Although romaine lettuce had lower levels of phenolics and antioxidant capacity compared to other common vegetables, its contribution to total antioxidant capacity and antineurodegenerative effect in human diets would be higher because of higher amounts of its daily per capita consumption compared to other common vegetables.

  7. Cross contamination of Escherichia coli O157:H7 between lettuce and wash water during home-scale washing.

    Science.gov (United States)

    Jensen, Dane A; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D; Schaffner, Donald W

    2015-04-01

    Lettuce and leafy greens have been implicated in multiple foodborne disease outbreaks. This study quantifies cross contamination between lettuce pieces in a small-scale home environment. A five-strain cocktail of relevant Escherichia coli O157:H7 strains was used. Bacterial transfer between single inoculated lettuce leaf pieces to 10 non-inoculated lettuce leaf pieces that were washed in a stainless steel bowl of water for 30 s, 1 min, 2 min, and 5 min was quantified. Regardless of washing time, the wash water became contaminated with 90-99% of bacteria originally present on the inoculated lettuce leaf piece. The E. coli O157:H7 concentration on initially inoculated leaf pieces was reduced ∼ 2 log CFU. Each initially uncontaminated lettuce leaf piece had ∼ 1% of the E. coli O157:H7 from the inoculated lettuce piece transferred to it after washing, with more transfer occurring during the shortest (30 s) and longest (5 min) wash times. In all cases the log percent transfer rates were essentially normally distributed. In all scenarios, most of the E. coli O157:H7 (90-99%) transferred from the inoculated lettuce pieces to the wash water. Washing with plain tap water reduces levels of E. coli O157:H7 on the inoculated lettuce leaf pieces, but also spreads contamination to previously uncontaminated leaf pieces. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Scientific rationale for cos lettuce growing technology Lactuca sativa var. longifolia L. in the Forest-Steppe of Ukraine

    Directory of Open Access Journals (Sweden)

    Н. В. Лещук

    2014-04-01

    Full Text Available Scientifically validated items of growing technology disclosed for cos lettuce marketable products in the conditions of Forest-Steppe of Ukraine. Impact of environmental factors onto growth and development of Lactuca sativa var. longifolia L. plants. Sowing terms established for the seed of cos lettuce at field-seeded growing. Development parameters are quoted for plant productivity indices and marketable product indices for cos lettuce of national and foreign breeding. According to VCU characteristics a  typical model has been designed for the cos lettuce indices of suitability for dissemination in Ukraine.

  9. Análise genética em um dialelo de alface Genetic analysis in a lettuce diallel

    Directory of Open Access Journals (Sweden)

    Francisco José da Silva Lédo

    2001-03-01

    Full Text Available Este trabalho teve por objetivo estimar parâmetros genéticos em um dialelo de alface, segundo o método de Jinks & Hayman. O experimento foi conduzido em casa de vegetação, na Universidade Federal de Viçosa, no período de 20/10 a 12/12/96. O delineamento experimental adotado foi o de blocos casualizados, com três repetições. Utilizaram-se vasos com 4,5 dm3 de substrato e uma planta por vaso (parcela. Foram avaliadas seis cultivares de alface (Vitória de Verão, Nativa, Regina de Verão, Maravilha de Verão, Grand Rapids e Mimosa e seus respectivos híbridos F1. Avaliaram-se os seguintes caracteres: matéria fresca da parte aérea (MFPA; matéria seca da parte aérea (MSPA, folhas (MSF e raiz (MSR; número de folhas/planta (NUF; e comprimento do caule (CC. Foram detectadas evidências de epistasia nos caracteres MSPA, NUF e CC. Na MFPA a variação de natureza aditiva contribuiu predominantemente para a variabilidade genética observada entre pais e seus híbridos F1. Evidenciou-se a predominância de efeitos gênicos de dominância no controle gênico dos caracteres MSF e MSR. As estimativas do coeficiente de determinação genotípico no sentido amplo ( sobre MFPA, MSF e MSR foram de 0,84, 0,85 e 0,90, respectivamente, e restrito ( 0,66, 0,45 e 0,49.This work aimed to estimate genetic parameters in a lettuce diallel, according to the Jinks & Hayman's method. The experiment was carried out in a greenhouse, at the Universidade Federal de Viçosa, from October 20 to December 12, 1996. The experimental design used was a randomized complete blocks, with three replications. Pots with 4,5 dm³ of substrate and one plant/pot (plot were used. Six lettuce cultivars and their respective F1 hybrids were evaluated. The following characters were evaluated: fresh matter of aerial part (FMAP; dry matter of aerial part (DMAP, leaves (DML and roots (DMR; number of leaves/plant (NUL; and stem height (SH. Some evidences of epistasis were detected for

  10. Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

    Science.gov (United States)

    Chen, Xiaoyulong; Pizzatti, Cristina; Bonaldi, Maria; Saracchi, Marco; Erlacher, Armin; Kunova, Andrea; Berg, Gabriele; Cortesi, Paolo

    2016-01-01

    Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (106 CFU/mL) were applied to S. sclerotiorum inoculated substrate in a growth chamber 1 week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40 and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP) marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM). The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces' capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on 2-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM) observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to 3 weeks by quantifying its

  11. Biological control of lettuce drop and host plant colonization by rhizospheric and endophytic streptomycetes

    Directory of Open Access Journals (Sweden)

    Xiaoyulong eChen

    2016-05-01

    Full Text Available Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (106 CFU/mL were applied to S. sclerotiorum inoculated substrate in a growth chamber one week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40% and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM. The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces’ capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on two-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to

  12. Acúmulo de nutrientes pela alface destinada à produção de sementes Nutrients uptake by lettuce plants for seed production

    Directory of Open Access Journals (Sweden)

    C Kano

    2011-03-01

    Full Text Available O objetivo deste trabalho foi determinar a curva de acúmulo de nutrientes pela planta de alface destinada à produção de sementes. O experimento foi conduzido na Fazenda Experimental São Manuel, pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista, no período de 25/09/03 a 19/02/04. O delineamento experimental utilizado foi em blocos ao acaso com cinco repetições e seis tratamentos (épocas de coleta das plantas: 0, 20, 34, 49, 69 e 112 dias após o transplante (DAT. Foi utilizada a alface crespa cultivar Verônica, sendo avaliados o acúmulo da massa seca e de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn na parte aérea das plantas. O maior incremento da massa seca das plantas ocorreu após o ponto comercial (34 DAT. O período de maior demanda de macronutrientes foi entre o início do pendoamento e o início do florescimento. Observa-se que para a maioria dos micronutrientes o período de maior exigência foi após o início do florescimento. A ordem decrescente de acúmulo de nutrientes foi: K>N>Ca>Mg>P>S>Fe>Mn>Zn>B>Cu.The nutrients uptake curve of lettuce plants for seed production was evaluated. The experiment was carried out from September 2003 to February 2004 at the Faculdade de Ciências Agronômicas of the Universidade Estadual Paulista, in Botucatu, São Paulo State, Brazil. A randomized block design was used, with five replicates and six treatments (periods of plant collection: 0, 20, 34, 49, 69 and 112 days after transplant (DAT. We utilized the Verônica lettuce cultivar and evaluated the dry mass and the N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn accumulated in the aboveground part of the plants. The greatest increase in the plant dry matter occurred after the marketable point (34 DAT. The period of greatest demand for nutrients was between the beginning of the stem elongation stage and the beginning of the flowering stage. We also observed that for most micronutrients the period of highest demand

  13. Desempenho de sistemas consorciados de cenoura e alface avaliados através de métodos uni e multivariados Biological performance of carrot and lettuce intercropping systems as assessed through uni- and multivariate methods

    Directory of Open Access Journals (Sweden)

    Francisco Bezerra Neto

    2007-12-01

    , observou-se diferença significativa entre os valores dos índices combinados (produtividade equivalente de cenoura, eficiência produtiva, uso eficiente da terra e escore da variável canônica apenas quando eles foram avaliados através do escore normalizado da variável canônica, com maior eficiência dos sistemas quando a cenoura foi consorciada com a alface 'Lucy Brown'. Os sistemas consorciados de cenoura 'Alvorada' + alface 'Lucy Brown' ou de cenoura 'Brasília' + alface 'Lucy Brown' são aqueles a serem indicados ao produtor.Intercropping experiments' data analysis is usually a complex task, as compared to those data analysis from sole crops. In these cases are recommended univariate analysis of variance for each crop yield; intercropping combined systems yields; productive efficiency measured with data envelopment analysis (DEA models; and multivariate analysis. In this work we evaluated the biological performance of carrot and crisphead lettuce intercropping systems through uni- and multivariate methods. Two experiments (one in intercropping and another in sole crop were carried out in a randomized complete block design with four replications. The intercropping experiment was designed in a 2 x 4 + 2 factorial scheme, with the treatments stemmed from the combination of two carrot cultivars (Alvorada and Brasília with four crisphead lettuce cultivars (Lucy Brown, Tainá, Laurel and Verônica plus two carrot cultivars in sole crop. The treatments of the experiment in sole crop consisted of those crisphead lettuce cvs. tested in intercropping experiment. The evaluated traits in lettuce and carrot crops were shoot fresh mass and commercial root yield, respectively. Uni- and multivariate analyses of variance were accomplished on these crop traits in function of the tested treatment-factors. The multivariate approach was more informative as compared to the univariated method, as it allowed better discrimination of the treatment-factors, beyond the description of the

  14. Qualidade de águas residuárias e salobra utilizadas no cultivo hidropônico de três cultivares de alface crespa

    Directory of Open Access Journals (Sweden)

    José Emídio de Albuquerque Júnior

    2016-04-01

    Full Text Available O reúso de efluentes tratados não é uma prática nova, no entanto, há um interesse crescente em relação à necessidade de sua reutilização. Objetivou-se avaliar a caraterização das águas residuárias domestica e do reator UASB e água salobra de poço para o cultivo hidropônico de alface crespa. O experimento foi conduzido em ambiente protegido com sistema hidropônico. Delineamento experimental foi em blocos casualizados com esquema fatorial 7 x 3, três repetições sendo, 7 soluções hidropônicase três cultivares de alface. A parcela experimental, S1=solução de Furlani; S2=água residuária domestica; S3=água residuária domestica otimizada; S4=água de poço; S5=água de poço otimizada; S6=água residuária (UASB e S7=água residuária (UASB otimizada, subparcela três cultivares de alface. O pH das águas residuárias foram de 7,7 e 7,4 (Poço; 7,4 e 8,0 (Esgoto bruto e, 7,2 e 8,2 (Extrabes. A (CE foram 0,957 e 1,002 (Poço; 2,133 e 2,368 (Esgoto bruto e (Extrabes 2,502 e 2,4 09 dS m-1. O uso de soluções minerais nutritivas utilizando água residuária é viável quando utilizado em sistemas hidropônicos, sendo indicado para principalmente para região do semiárido brasileiro e quando se faz uso de água de irrigação de qualidade inferior na produção de hortaliças.Quality of wastewater and brackish water used in the hydroponic cultivation of three varieties of curly lettuce Abstract: The reuse of treated wastewater is not a new practice, however, there is a growing interest in the need for re-use. The objective was to evaluate the Characterisation of domestic wastewater and UASB and brackish well for hydroponic lettuce. The experiment was conducted in a protected environment with hydroponically. Experimental design was a randomized block with factorial 7 x 3, three replications and 7 hydroponic solutions and three lettuce cultivars. The experimental portion, S1 = Furlani solution; S2 = domestic wastewater; S3

  15. Transcriptome profiling of two olive cultivars in response to infection by the CoDiRO strain of Xylella fastidiosa subsp. pauca.

    Science.gov (United States)

    Giampetruzzi, Annalisa; Morelli, Massimiliano; Saponari, Maria; Loconsole, Giuliana; Chiumenti, Michela; Boscia, Donato; Savino, Vito N; Martelli, Giovanni P; Saldarelli, Pasquale

    2016-06-27

    The recent Xylella fastidiosa subsp. pauca (Xfp) outbreak in olive (Olea europaea) groves in southern Italy is causing a destructive disease denoted Olive Quick Decline Syndrome (OQDS). Field observations disclosed that Xfp-infected plants of cv. Leccino show much milder symptoms, than the more widely grown and highly susceptible cv. Ogliarola salentina. To determine whether these field observations underlie a tolerant condition of cv. Leccino, which could be exploited for lessening the economic impact of the disease on the local olive industry, transcriptional changes occurring in plants of the two cultivars affected by Xfp were investigated. A global quantitative transcriptome profiling comparing susceptible (Ogliarola salentina) and tolerant (Leccino) olive cultivars, infected or not by Xfp, was done on messenger RNA (mRNAs) extracted from xylem tissues. The study revealed that 659 and 447 genes were differentially regulated in cvs Leccino and Ogliarola upon Xfp infection, respectively, whereas 512 genes were altered when the transcriptome of both infected cultivars was compared. Analysis of these differentially expressed genes (DEGs) shows that the presence of Xfp is perceived by the plants of both cultivars, in which it triggers a differential response strongly involving the cell wall. Up-regulation of genes encoding receptor-like kinases (RLK) and receptor-like proteins (RLP) is the predominant response of cv. Leccino, which is missing in cv. Ogliarola salentina. Moreover, both cultivars react with a strong re-modelling of cell wall proteins. These data suggest that Xfp elicits a different transcriptome response in the two cultivars, which determines a lower pathogen concentration in cv. Leccino and indicates that this cultivar may harbor genetic constituents and/or regulatory elements which counteract Xfp infection. Collectively these findings suggest that cv. Leccino is endowed with an intrinsic tolerance to Xfp, which makes it eligible for further studies

  16. DESEMPENHO DE CULTIVARES DE ALFACE AMERICANA EM AMBIENTES SOMBREADOS NA REGIÃO DO SUBMÉDIO SÃO FRANCISCO-BA

    Directory of Open Access Journals (Sweden)

    CARMEM VALDENIA DA SILVA SANTANA

    2009-01-01

    Full Text Available The lettuce is a leafy vegetable and when it is cultivated in regions of intense solar radiation it can¿t develop it's full genetic potential. In this direction this work had the objective of evaluating the productivity of the Butterhead lettuce cultivar using different types of screens in the region of the Submédio São Francisco. The experiment was carried out in raised planting beds, using black screens with 30 and 50% of shading, white screens and in the open sun. The statistical design was the factorial 2x4 and the means were compared by the Turkey test at 5% of probability. In each treatment a termohigrometre and temometers at 40 cm from the ground were coupled with a black globe to get the radiant thermal load, the temperature of the air and the humidity index. At the end of the trial chlorophyll, the diameter of the head, plant height, the number of leaves per plant, the leaf area, fresh and dry weight of plants were collected. The screens affected the parameters analyzed and the treatment PS and TB of shading were the best for commercial parameters.

  17. Cisgenic Rvi6 scab-resistant apple lines show no differences in Rvi6 transcription when compared with conventionally bred cultivars.

    Science.gov (United States)

    Chizzali, Cornelia; Gusberti, Michele; Schouten, Henk J; Gessler, Cesare; Broggini, Giovanni A L

    2016-03-01

    The expression of the apple scab resistance gene Rvi6 in different apple cultivars and lines is not modulated by biotic or abiotic factors. All commercially important apple cultivars are susceptible to Venturia inaequalis, the causal organism of apple scab. A limited number of apple cultivars were bred to express the resistance gene Vf from the wild apple genotype Malus floribunda 821. Positional cloning of the Vf locus allowed the identification of the Rvi6 (formerly HcrVf2) scab resistance gene that was subsequently used to generate cisgenic apple lines. It is important to understand and compare how this resistance gene is transcribed and modulated during infection in conventionally bred cultivars and in cisgenic lines. The aim of this work was to study the transcription pattern of Rvi6 in three classically bred apple cultivars and six lines of 'Gala' genetically modified to express Rvi6. Rvi6 transcription was analyzed at two time points using quantitative real-time PCR (RT-qPCR) following inoculation with V. inaequalis conidia or water. Rvi6 transcription was assessed in relation to five reference genes. β-Actin, RNAPol, and UBC were the most suited to performing RT-qPCR experiments on Malus × domestica. Inoculation with V. inaequalis conidia under conditions conducive to scab infection failed to produce any significant changes to the transcription level of Rvi6. Rvi6 expression levels were inconsistent in response to external treatments in the different apple cultivars, and transgenic, intragenic or cisgenic lines.

  18. Postharvest transfer and survival of Salmonella enterica serotype enteritidis on living lettuce.

    Science.gov (United States)

    Waitt, J A; Kuhn, D D; Welbaum, G E; Ponder, M A

    2014-02-01

    The potential for postharvest transfer of Salmonella to 'living lettuce' is not well understood. In this study, the transfer of Salmonella enterica Enteritidis (6 log CFU g(-1) ) from worker hands or contaminated roots to leaves of living lettuce was quantified. Transfer rates of Salmonella from contaminated gloves to sequentially handled lettuce heads ranged from 94% to head 1, 82% to head 2 and 69% to head 3. On average, 2.9 ± 0.1 log CFU g(-1) (64%) Salmonella was transferred from inoculated roots to leaves resulting from typical postharvest handling activities for living lettuce. Salmonella persisted on leaves stored at recommended storage temperatures (4°C) and increased 0.5 log CFU g(-1) when stored at temperature abuse conditions (12°C). Salmonella increased 1.6 log CFU g(-1) on roots after 18-day storage at 12°C, emphasizing the need to maintain temperature control to reduce the risk of human illness. Hydroponically grown lettuce packaged in plastic clamshells with intact roots, marketed as 'living lettuce', is increasing in popularity due to its extended shelf life. This study demonstrates the transfer of Salmonella from contaminated worker hands and contaminated roots to leaves where it persisted at 4°C for 18 day. Temperature abuse (12°C) increased Salmonella on roots and leaves. These findings suggest that failure to maintain temperatures below 12°C can pose a risk for consumers purchasing living lettuce at markets where recommended storage temperatures are not maintained. © 2013 The Society for Applied Microbiology.

  19. Phyllosphere Microbiota Composition and Microbial Community Transplantation on Lettuce Plants Grown Indoors

    Science.gov (United States)

    Williams, Thomas R.

    2014-01-01

    ABSTRACT The aerial surfaces of plants, or phyllosphere, are microbial habitats important to plant and human health. In order to accurately investigate microbial interactions in the phyllosphere under laboratory conditions, the composition of the phyllosphere microbiota should be representative of the diversity of microorganisms residing on plants in nature. We found that Romaine lettuce grown in the laboratory contained 10- to 100-fold lower numbers of bacteria than age-matched, field-grown lettuce. The bacterial diversity on laboratory-grown plants was also significantly lower and contained relatively higher proportions of Betaproteobacteria as opposed to the Gammaproteobacteria-enriched communities on field lettuce. Incubation of field-grown Romaine lettuce plants in environmental growth chambers for 2 weeks resulted in bacterial cell densities and taxa similar to those on plants in the field but with less diverse bacterial populations overall. In comparison, the inoculation of laboratory-grown Romaine lettuce plants with either freshly collected or cryopreserved microorganisms recovered from field lettuce resulted in the development of a field-like microbiota on the lettuce within 2 days of application. The survival of an inoculated strain of Escherichia coli O157:H7 was unchanged by microbial community transfer; however, the inoculation of E. coli O157:H7 onto those plants resulted in significant shifts in the abundance of certain taxa. This finding was strictly dependent on the presence of a field-associated as opposed to a laboratory-associated microbiota on the plants. Phyllosphere microbiota transplantation in the laboratory will be useful for elucidating microbial interactions on plants that are important to agriculture and microbial food safety. PMID:25118240

  20. A PCR procedure for the detection of Giardia intestinalis cysts and Escherichia coli in lettuce.

    Science.gov (United States)

    Ramirez-Martinez, M L; Olmos-Ortiz, L M; Barajas-Mendiola, M A; Giono Cerezo, S; Avila, E E; Cuellar-Mata, P

    2015-06-01

    Giardia intestinalis is a pathogen associated with foodborne outbreaks and Escherichia coli is commonly used as a marker of faecal contamination. Implementation of routine identification methods of G. intestinalis is difficult for the analysis of vegetables and the microbiological detection of E. coli requires several days. This study proposes a PCR-based assay for the detection of E. coli and G. intestinalis cysts using crude DNA isolated from artificially contaminated lettuce. The G. intestinalis and E. coli PCR assays targeted the β-giardin and uidA genes, respectively, and were 100% specific. Forty lettuces from local markets were analysed by both PCR and light microscopy and no cysts were detected, the calculated detection limit was 20 cysts per gram of lettuce; however, by PCR, E. coli was detected in eight of ten randomly selected samples of lettuce. These data highlight the need to validate procedures for routine quality assurance. These PCR-based assays can be employed as alternative methods for the detection of G. intestinalis and E. coli and have the potential to allow for the automation and simultaneous detection of protozoa and bacterial pathogens in multiple samples. Significance and impact of the study: There are few studies for Giardia intestinalis detection in food because methods for its identification are difficult for routine implementation. Here, we developed a PCR-based method as an alternative to the direct observation of cysts in lettuce by light microscopy. Additionally, Escherichia coli was detected by PCR and the sanitary quality of lettuce was evaluated using molecular and standard microbiological methods. Using PCR, the detection probability of Giardia cysts inoculated onto samples of lettuce was improved compared to light microscopy, with the advantage of easy automation. These methods may be employed to perform timely and affordable detection of foodborne pathogens. © 2015 The Society for Applied Microbiology.

  1. Photoprotection vs. Photoinhibition of Photosystem II in Transplastomic Lettuce (Lactuca sativa) Dominantly Accumulating Astaxanthin.

    Science.gov (United States)

    Fujii, Ritsuko; Yamano, Nami; Hashimoto, Hideki; Misawa, Norihiko; Ifuku, Kentaro

    2016-07-01

    Transplastomic (chloroplast genome-modified; CGM) lettuce that dominantly accumulates astaxanthin grows similarly to a non-transgenic control with almost no accumulation of naturally occurring photosynthetic carotenoids. In this study, we evaluated the activity and assembly of PSII in CGM lettuce. The maximum quantum yield of PSII in CGM lettuce was <0.6; however, the quantum yield of PSII was comparable with that in control leaves under higher light intensity. CGM lettuce showed a lower ability to induce non-photochemical quenching (NPQ) than the control under various light intensities. The fraction of slowly recovering NPQ in CGM lettuce, which is considered to be photoinhibitory quenching (qI), was less than half that of the control. In fact, 1 O 2 generation was lower in CGM than in control leaves under high light intensity. CGM lettuce contained less PSII, accumulated mostly as a monomer in thylakoid membranes. The PSII monomers purified from the CGM thylakoids bound echinenone and canthaxanthin in addition to β-carotene, suggesting that a shortage of β-carotene and/or the binding of carbonyl carotenoids would interfere with the photophysical function as well as normal assembly of PSII. In contrast, high accumulation of astaxanthin and other carbonyl carotenoids was found within the thylakoid membranes. This finding would be associated with the suppression of photo-oxidative stress in the thylakoid membranes. Our observation suggests the importance of a specific balance between photoprotection and photoinhibition that can support normal photosynthesis in CGM lettuce producing astaxanthin. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Genetic fingerprinting of mutant rose cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S; Prasad, K V; Singh, K P; Singh, A.P. [Division of Floriculture and Landscaping, Indian Agricultural Research Institute, Pusa, New Delhi (India)], E-mail: kvprasad66@gmail.com

    2008-07-01

    Six rose mutants evolved at the Indian Agricultural Research Institute, New Delhi from four parent cultivars were characterized based on RAPD markers. Contrary to the earlier findings our effort has conclusively proven that the RAPD markers are indeed robust tools to discern the mutants from their parents. Among 40 primers screened, 7 primers produced inconsistent banding pattern. The number of polymorphic bands varied between 4 (OPA 14) and 10 (OPA1) with an average of 6.5 bands per primer. The percentage polymorphism ranged from 62.5 (OPM 9) to 100 percent (OPA 1). Most of the primers produced monomorphic bands between parent and mutant rose cultivars. When primer OPA 2 was used a specific band of 2.5 kb was noticed in mutant cv. Pusa Urmil and cv. Pusa Abhishek but was absent in parent cv. Jantar Mantar. A polymorphic band of 750 bp was noticed in the parent Kiss of Fire and helped in differentiating the parent from its mutant when amplified with OPK 3. Primer OPS 16 produced discriminatory band of 800 bp in mutant cv. Pink Sport of Montezuma while it was absent in its parent cv. Montezuma. Another specific band of 650 bp was present in parent cv. Montezuma and absent in its mutant cv. Pink Sport of Montezuma signifying the uniqueness of the mutant. Primer OPM 5 brought out distinct polymorphism among the parent Jantar Mantar and its three mutants with absence of a specific band of 1.5 kb in the parent. The four parents and 6 mutants were divided into four distinct groups in the Dendogram constructed by UPGMA method. The most genetically similar cultivar among the 10 cultivars analyzed are Montezuma and its pink sport of Montezuma whereas Abhisarika a mutant of cv. Kiss of Fire was distinctly different and formed a separate cluster. (author)

  3. Relative competitiveness of soybean cultivars with barnyardgrass

    Directory of Open Access Journals (Sweden)

    Marlon Ouriques Bastiani

    Full Text Available ABSTRACT The aim of this work was to evaluate the competitiveness between soybean cultivars and barnyardgrass, based on morphological and physiological characteristics of species. The experiments were conducted in completely randomized experimental design, with 4 replications. In the first study, for both soybean and barnyardgrass, it was determined the population of plants in which shoot dry matter became constant and independent of the population (16 plants∙pot−1 or 400 plants∙m−2. In the second study, 2 experiments were conducted to evaluate the competitiveness of BMX Apolo RR and BMX Potência RR soybean cultivars with barnyardgrass plants, both carried out in replacement series under different proportions of plants∙pot−1 (100:0; 75:25; 50:50; 25:75 and 0:100 between the crop and the weed. The analysis of the species competitiveness was determined through diagrams applied to replacement series experiments and use of relative competitiveness indexes. At 44 days after the emergence of species, the physiological and morphological parameters of the crop and the weed were evaluated. The BMX Apolo RR and BMX Potência RR soybean cultivars show similar competitiveness when competing with the barnyardgrass; therefore, the ability of one species to interfere on another is equivalent. For plant height, barnyardgrass displays higher competitiveness compared to BMX Apolo RR, with early cycle and short height. The intraspecific competition is more important to barnyardgrass than interspecific competition with soybean cultivars, resulting in negative effects on the morphological and physiological characteristics of species.

  4. Epistatic association mapping in homozygous crop cultivars.

    Directory of Open Access Journals (Sweden)

    Hai-Yan Lü

    Full Text Available The genetic dissection of complex traits plays a crucial role in crop breeding. However, genetic analysis and crop breeding have heretofore been performed separately. In this study, we designed a new approach that integrates epistatic association analysis in crop cultivars with breeding by design. First, we proposed an epistatic association mapping (EAM approach in homozygous crop cultivars. The phenotypic values of complex traits, along with molecular marker information, were used to perform EAM. In our EAM, all the main-effect quantitative trait loci (QTLs, environmental effects, QTL-by-environment interactions and QTL-by-QTL interactions were included in a full model and estimated by empirical Bayes approach. A series of Monte Carlo simulations was performed to confirm the reliability of the new method. Next, the information from all detected QTLs was used to mine novel alleles for each locus and to design elite cross combination. Finally, the new approach was adopted to dissect the genetic basis of seed length in 215 soybean cultivars obtained, by stratified random sampling, from 6 geographic ecotypes in China. As a result, 19 main-effect QTLs and 3 epistatic QTLs were identified, more than 10 novel alleles were mined and 3 elite parental combinations, such as Daqingdou and Zhengzhou790034, were predicted.

  5. Breeding of cocksfoot cultivars with different maturity

    Directory of Open Access Journals (Sweden)

    Babić Snežana

    2017-01-01

    Full Text Available One of the most important criteria in breeding process of perennial grasses is maturity. Cultivars with different maturity play a very important role in utilization of perennial grasses, by providing the ability to create a mixture of different aspects utilization and time. The first grass species in Serbia whose breeding program involved this criterion was cocksfoot (Dactylis glomerata L.. In general cocksfoot is early to medium-early in maturity in comparison with other grasses and legumes, and that is mayor problem since in the optimum phase for cutting, cocksfoot is often earlier then other species in mixtures. As a result of this work, in the previous period, two cultivars of different maturity were released, Kruševačka 24 (K-24 and Kruševačka 25 (K-25. K-24 is medium and K-25 is late in maturity. New material is adapted to local agro-ecological conditions and productive in the same time. In breeding process of both cultivars initial material originated from autochthonous populations collected in eastern and central Serbia. Material from the wild flora is selected based on medium and late maturity which is already adapted and has good productivity. We applied the standard method of phenotypic recurrent selection with the creation of synthetic varieties by polycross.

  6. Incidence of Lettuce mosaic virus in lettuce and its detection by polyclonal antibodies produced against recombinant coat protein expressed in Escherichia coli.

    Science.gov (United States)

    Sharma, Prachi; Sharma, Susheel; Singh, Jasvir; Saha, Swati; Baranwal, V K

    2016-04-01

    Lettuce mosaic virus (LMV), a member of the genus Potyvirus of family Potyviridae, causes mosaic disease in lettuce has recently been identified in India. The virus is seed borne and secondary infection occurs through aphids. To ensure virus freedom in seeds it is important to develop diagnostic tools, for serological methods the production of polyclonal antibodies is a prerequisite. The coat protein (CP) gene of LMV was amplified, cloned and expressed using pET-28a vector in Escherichia coli BL21DE3 competent cells. The LMV CP was expressed as a fusion protein containing a fragment of the E. coli His tag. The LMV CP/His protein reacted positively with a commercial antiserum against LMV in an immunoblot assay. Polyclonal antibodies purified from serum of rabbits immunized with the fusion protein gave positive results when LMV infected lettuce (Lactuca sativa) was tested at 1:1000 dilution in PTA-ELISA. These were used for specific detection of LMV in screening lettuce accessions. The efficacy of the raised polyclonal antiserum was high and it can be utilized in quarantine and clean seed production. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Evaluation of Garlic Cultivars for Polyphenolic Content and Antioxidant Properties

    Science.gov (United States)

    Cheng, Siqiong; Li, Panpan; Du, Junna; Chang, Yanxia; Meng, Huanwen

    2013-01-01

    Two phenolic compound parameters (total phenolic and flavonoid contents) and 5 antioxidant parameters (DPPH [2, 2-diphenyl-1-picrylhydrazyl] radical scavenging activity, HRSC (hydroxyl radical scavenging capacity), FRAP (ferric ion reducing antioxidant power), CUPRAC (cupric ion reducing antioxidant capacity), and MCA (metal chelating activity) were measured in bulbs and bolts of 43 garlic cultivars. The bulbs of cultivar ‘74-x’ had the highest phenolic content (total phenolic, flavonoids) and the strongest antioxidant capacity (DPPH, FRAP, and CUPRAC), followed by bulbs of cultivar ‘Hanzhong purple’; the bulbs of cultivar ‘Gailiang’ had the lowest phenolic content and antioxidant capacity (FRAP, CUPRAC, MCA). The bolts of ‘Hanzhong purple’ also had higher phenolic content. Principal components analysis (PCA) separated the cultivars into 3 groups according to phenolic and flavonoid contents and strength of antioxidant activity. The first group had higher HRSC, FRAP, and flavonoid content; the second group had higher total phenolic content and MCA; some cultivars in the third group had higher HRSC and FRAP. All 8 test garlic bulb extracts successfully prevented Human Vascular Endothelial Cell death and significantly prevented reactive-oxygen species (ROS) formation in oxidative stress model, in which cultivar ‘74-x’ had highest protection capability, following by cultivar ‘Hanzhong purple’, and the bulbs of cultivar ‘No. 105 from Korea’ had the lower protection capability against cell death and ROS formation. The protection capability in vivo of these garlic cultivars was consistent with their phenolic content and antioxidant capacity. PMID:24232741

  8. Study the Reaction of Some Barley Cultivars to Rhizoctonia solani AG-8, the Causal Agent of Root Rot Disease

    Directory of Open Access Journals (Sweden)

    M. Yazdani Kohanstani

    2016-03-01

    introduced as more susceptible cultivars against Rhizoctonia root rot disease. These results provide the possibility of the use of tolerant cultivars to reduce disease damage, and the possibility of transmission of resistance genes to R. solani of tolerant or resistant genotypes to susceptible commercial ones.

  9. Preliminary investigations of the rhizosphere nature of hydroponically grown lettuces

    Science.gov (United States)

    Antunes, Inês; Paille, Christel; Lasseur, Christophe

    Due to capabilities of current launchers, future manned exploration beyond the Earth orbit will imply long journeys and extended stays on planet surfaces. For this reason, it is of a great importance to develop a Regenerative Life Support System that enables the crew to be, to a very large extent, metabolic consumables self-sufficient. In this context, the European Space Agency, associated with a scientific and engineering con-sortium, initiated in 1989 the Micro-Ecological Life Support System Alternative (MELiSSA) project. This concept, inspired on a terrestrial ecosystem (i.e. a lake), comprises five intercon-nected compartments inhabited by micro-organisms and higher-plants aiming to produce food, fresh water, and oxygen from organic waste, carbon dioxide, and minerals. Given the important role of the higher-plant compartment for the consumption of carbon dioxide and the production of oxygen, potable water, and food, it was decided to study the microbial communities present in the root zone of the plants (i.e. the rhizosphere), and their synergistic and antagonistic influences in the plant growth. This understanding is important for later investigations concerning the technology involved in the higher plant compartment, since the final goal is to integrate this compartment inside the MELiSSA loop and to guarantee a healthy and controlled environment for the plants to grow under reduced-gravity conditions. To perform a preliminary assessment of the microbial populations of the root zone, lettuces were grown in a hydroponic system and their growth was characterized in terms of nutrient uptake, plant diameter, and plant wet and dry weights. In parallel, the microbial population, bacteria and fungi, present in the hydroponic medium and also inside and outside the roots were analyzed in terms of quantity and nature. The goal of this presentation is to give a preliminary review in the plant root zone of the micro-organisms communities and as well their proportions

  10. Reação de cultivares de trigo à ferrugem da folha e mancha amarela e responsividade a fungicidas Reaction of wheat cultivars to leaf rust and yellow spot and responsiveness to fungicides

    Directory of Open Access Journals (Sweden)

    Nédio Rodrigo Tormen

    2013-02-01

    Full Text Available Com o objetivo de avaliar a reação de cultivares de trigo à ferrugem da folha, causada por Puccinia triticina, e mancha amarela, causada por Drechslera tritici-repentis, e sua responsividade ao controle químico com fungicidas, foi conduzido experimento de campo durante os invernos de 2009 e 2010, Itaara-RS. As cultivares avaliadas foram 'FCEP 51', 'FCEP 52', 'CD 114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' e 'OR Pampeano'; na safra 2010, a cultivar 'CD 114' foi substituída pela OR Quartzo. Os tratamentos avaliados foram: P1 - testemunha sem aplicação de fungicida; P2 - fempropimorfe (560g ha-1 de i.a.; P3 - azoxistrobina + ciproconazol (60+24g ha-1 de i.a.; e P4 - piraclostrobina + metconazol (60+97,5g ha-1 de i.a.. Após a segunda aplicação, efetuaram-se avaliações semanais de severidade das doenças, cujos dados foram utilizados para o cálculo da Área Abaixo da Curva de Progresso da Doença (AACPD. Também foram determinados a produtividade e o peso do hectolitro. No que se refere à suscetibilidade às doenças, as cultivares estudadas apresentaram respostas distintas de um ano para o outro. Para ferrugem, o comportamento mostrou-se similar em ambos os anos, enquanto que, para mancha amarela, houve variação. Quanto à resposta ao controle químico, ocorreram variações de acordo com o patógeno e com o grau de suscetibilidade das cultivares. O uso integrado de resistência genética e controle químico mostrou-se mais efetivo para ferrugem da folha.Aiming to evaluate the susceptibility of wheat cultivars to leaf rust and yellow spot and their responsiveness to chemical fungicides, two field trials were carried out, during 2009 and 2010 winter's. The cultivars evaluated were: 'FCEP 51', 'FCEP 52', 'CD114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' and 'OR Pampeano'. In 2010, the 'CD 114' cultivar was replaced by Quartzo

  11. Preference and life history traits of Aphelinus abdominalis (Hymenoptera: Aphelinidae) when offered different development stages of the lettuce aphid Nasonovia ribisnigri (Hemiptera: Aphididae)

    DEFF Research Database (Denmark)

    Shrestha, Govinda; Skovgård, Henrik; Steenberg, Tove

    2015-01-01

    stages of the lettuce aphid were exposed for parasitism compared with older developmental stages. This pattern was supported in the choice experiment where significantly more 2nd instar lettuce aphids were parasitised than alatoid 4th instars, with Manly’s preference index (mean ± SE) for the former...... %) were found across all host stages of the lettuce aphid....

  12. Selection for resistance to Verticillium wilt caused by race 2 isolates of Verticillium dahliae in accessions of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. The pathogen exists as two races (races 1 and 2) in lettuce, and complete resistance to race 1 is known. Resistance to race 2 isolates has not been reported, and production of race 1 re...

  13. Estimation Of Productive Value Of Czech Origin Scab-Resistant Apple Cultivars On Different Rootstocks

    Directory of Open Access Journals (Sweden)

    Sosna Ireneusz

    2014-12-01

    Full Text Available Apple cultivars resistant to scab are suitable for the conventional and organic cultivation. Rootstocks impact on the growth of trees, yield and fruit quality of scab-resistant cultivars were examined in the experiment conducted at Fruit Experimental Station - Samotwór near Wrocław, during the years 1998-2008. In the spring of 1998, the trees of five Czech origin scab-resistant apple cultivars ‘Rosana’, ‘Rubinola’, ‘Rajka’, ‘Goldstar’ and ‘Topaz’ each on M.9, P2, P60, P16 and P22 rootstocks were planted at a spacing of 3.5 × 1.2 m (2380 trees per hectare. The results of 11-year-long studies showed that ‘Rubinola’ and ‘Rajka’ were characterised by the strongest vigour, while ‘Rosana’ grew much weaker. Significant differences in the cumulative yield were not observed between cultivars, but rootstocks influenced cropping instantly. Trees on rootstock P60 had biggest cross-section area and canopy volume, and the highest cumulative yield. Fruit weight was highest from trees on M9 and P60. ‘Topaz’ and ‘Rosana’ formed significantly lightest fruits and ‘Goldstar’ the heaviest. Trees on the super-dwarfing P22 rootstock grew and yielded very weakly and produced very small fruits. The greatest susceptibility to powdery mildew (Podosphaera leucotricha was observed in ‘Topaz’ and ‘Rajka’. ‘Rubinola’ has the best potential for organic cultivation, especially on dwarfing rootstocks.

  14. Uso de diferentes doses de manipueira na cultura da alface em substituição à adubação mineral Use of different doses of cassava wastewater in lettuce crop in substitution of mineral fertilizer

    Directory of Open Access Journals (Sweden)

    Anamaria de S. Duarte

    2012-01-01

    Full Text Available Objetivou-se, neste trabalho, verificar o efeito ocasionado pelo uso de diferentes doses de manipueira nas características agronômicas da alface em substituição à adubação mineral. O referido estudo foi desenvolvido em uma área pertencente ao Departamento de Tecnologia Rural da Universidade Federal Rural de Pernambuco, Recife, PE, no período de maio a agosto de 2010. O experimento foi conduzido em ambiente protegido em delineamento inteiramente casualizado, com seis tratamentos compostos das seguintes doses: 0, 5, 15, 25, 45, 65 m³ ha-1 e cinco repetições. Utilizou-se a cultivar de alface Regina 2000, dispondo-se uma planta por vaso de 4 L. Foram avaliadas, em função das doses aplicadas, as seguintes características agronômicas da alface: área foliar, altura de planta, número de folhas, matéria fresca e matéria seca da alface. Ao final do experimento constatou-se que a dose de 45 m³ ha-1 foi a que propiciou maior ganho de altura de planta, área foliar e, consequentemente, também maior produção de matéria fresca e seca. Assim sendo, o uso da manipueira serviu como fonte de adubação para a cultura da alface, dependendo da dose aplicada.The main goal of this work was to evaluate the effect on agronomic characteristics of the lettuce when using different doses of cassava wastewater instead of mineral fertilizer. This study was conducted at the Departamento de Tecnologia Rural da Universidade Rural de Pernambuco, Recife, PE, from May to August 2010. The experiment was carried out under greenhouse conditions in a completely randomized blocks, with six treatments and five repetitions. Following doses were used: 0, 5, 15, 25, 45 and 65 m³ ha-1. The lettuce cultivar Regina 2000 was used (one plant per pot and leaf area, plant height, number of leaves, fresh leaf mass and dry leaf mass were evaluated for each dose of cassava wastewater. At the end of the experiment, the dose of 45 m³ ha-1 provided the best results by

  15. Cobertura do solo, produção de biomassa e teores de Mn e Zn de alface no sistema orgânico = Soil covering, biomass production, and Mn and Zn content of lettuce in organic system

    Directory of Open Access Journals (Sweden)

    Átila Francisco Mógor

    2009-10-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da cobertura do solo com aveia preta e manutenção da palha sobre o terreno, bem como cobertura do solo com filme de polietileno preto, sobre a produção de biomassa e teores de Mn e Zn em alface cultivada no sistema orgânico, por dois anos consecutivos. Utilizaram-se cinco tratamentos: solo sem cobertura, coberto com filme de polietileno preto, coberto com aveia acamada, coberto com aveia ceifada e solo coberto com aveia na sua forma natural,para o cultivo de três cultivares de alface. O experimento seguiu delineamento experimental de blocos ao acaso, com quatro repetições e análise estatística com parcelas subdivididas. Concluiu-se que o cultivo de alface em sucessão à aveia preta,sobre a palha, promoveu produção satisfatória e apresentou adequados teores demanganês e zinco, equivalentes àqueles encontrados na literatura em diferentes sistemas de cultivo, e a cobertura do solo com plástico preto promoveu produção satisfatória com maior acúmulo de Zn no primeiro ano e menor de Mn no segundo.The goal of this research was to evaluate the effect of soil covering with black oat straw, as well as soil covered with black plastic, on the production of biomass and levels of Mn and Zn in lettuce produced in an organic system, over two consecutive years. Five treatments were used: soil without cover, covered with black plastic,covered with laying oats, covered with harvested oats, and covered with oat straw in natural form, for growing three cultivars of lettuce. A randomized blocks design was used in a splitplot system, with four replications. It was concluded that soil covered with oat straw promoted satisfactory lettuce production, as well as adequate Mn and Zn content in plants,equivalent to those found in studies conducted under different growing systems; the soil covered with black plastic promoted satisfactory production and higher Zn content after thefirst year, and lower Mn

  16. Cadmium accumulation in different rice cultivars and screening for pollution-safe cultivars of rice.

    Science.gov (United States)

    Yu, Hui; Wang, Junli; Fang, Wei; Yuan, Jiangang; Yang, Zhongyi

    2006-11-01

    Large areas of contaminated land are being used for agricultural production in some countries due to the high demand for food. To minimize the influx of pollutants to the human food chain through consumption of agricultural products, we propose the concept of pollution-safe cultivars (PSCs), i.e. cultivars whose edible parts accumulate a specific pollutant at a level low enough for safe consumption, even when grown in contaminated soil. We tested the feasibility of the PSC concept by growing 43 cultivars of paddy rice (Oryza sativa L., including 20 normal and 23 hybrid cultivars) under a high (75.69-77.55 mg kg(-1)) and a low (1.75-1.85 mg kg(-1)) cadmium (Cd) exposure. These pot experiments took place in the spring and summer of 2004. At the low level of Cd exposure, 30 out of the 43 tested cultivars were found to be Cd-PSCs. Grain Cd concentrations were highly correlated (price grain is genotype-dependent and that the selection of PSCs is possible, at least at a certain level of soil contamination. No Cd-PSCs were found under the high level of Cd exposure. Yield was enhanced in some cultivars and depressed in others in response to elevated soil Cd, indicating that farmers cannot rely on yield depression as an indicator of toxicity of the grains. It is therefore important and feasible to screen for PSCs and to establish PSC breeding programs to effectively and efficiently reduce the risk of human exposure to soil pollutants, such as Cd, through crop consumption.

  17. Escherichia coli Contamination of Lettuce Grown in Soils Amended with Animal Slurry

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; Storm, Christina; Forslund, Anita

    2013-01-01

    A pilot study was conducted to assess the transfer of Escherichia coli from animal slurry fertilizer to lettuce, with E. coli serving as an indicator of fecal contamination and as an indicator for potential bacterial enteric pathogens. Animal slurry was applied as fertilizer to three Danish agric...... types between slurry, soil, and lettuce. The frequent finding of fecal-contaminated lettuce indicates that human pathogens such as Salmonella and Campylobacter can be present and represent food safety hazards.......A pilot study was conducted to assess the transfer of Escherichia coli from animal slurry fertilizer to lettuce, with E. coli serving as an indicator of fecal contamination and as an indicator for potential bacterial enteric pathogens. Animal slurry was applied as fertilizer to three Danish....... coli. A relatively higher frequency of E. coli in lettuce compared with the soil samples at harvest suggests environmental sources of fecal contamination, e.g., wildlife. The higher frequency was supported by the finding of 21 different PFGE types among the E. coli isolates, with only a few common PFGE...

  18. Respiration rate and ethylene production of fresh cut lettuce as affected by cutting grade

    Directory of Open Access Journals (Sweden)

    J. MARTÍNEZ

    2008-12-01

    Full Text Available For designing optimal polymeric films for modified atmosphere packaging of whole heads as well as for minimally fresh processed (fresh-cut Iceberg lettuce ‘Coolguard’, the effect of several cutting grades on respiration rate (RR and ethylene production at 5ºC was studied. According to common industrial practices cutting grades less than 0.5 cm, between 0.5 and 1 cm, and 2 cm length were selected. Results from four experiments were compared to those obtained for whole heads in which a homogenous range of 6 to 8 ml CO2 kg-1 h-1 in RR was found. Compared to whole heads, in fresh-cut lettuce the RR was 2-fold higher. The lowest cutting grade showed the highest respiration rate, and no significant differences in RR among lettuce pieces of intermediate and the highest grades were found. No ethylene production was detected in whole heads, while in minimally processed lettuce pieces only traces were found. For avoiding risks of anaerobic respiration and excessive CO2 levels within packages containing fresh-cut lettuce pieces lower than 0.5 cm length, films with relatively high O2 permeability like standard polypropylene or low-density polyethylene must be selected.;

  19. Occurrence of perchlorate in groundwater, paired farmland soil, lettuce, and rhizosphere soil from Chengdu, China.

    Science.gov (United States)

    Tang, Yulu; Zhong, Bifeng; Qu, Bing; Feng, Shujin; Ding, Sanglan; Su, Shijun; Li, Zhi; Gan, Zhiwei

    2017-05-24

    A total of 28 groundwater, paired farmland soil, lettuce, and its rhizosphere soil samples were collected from Chengdu, China to detect perchlorate levels and to evaluate the relationships of perchlorate concentrations among these matrices. The perchlorate concentrations in the groundwater, farmland soil, lettuce, and rhizosphere soil samples ranged from below detection limit to 60.2 μg L -1 , from below detection limit to 249 μg kg -1 dry weight (dw), from 2.07 to 1010 μg kg -1 wet weight, and from below detection limit to 314 μg kg -1 dw, respectively. Significant correlation was found in the perchlorate levels among the farmland soil, lettuce, and rhizosphere soil, suggesting that they have common pollution sources, or perchlorate might transfer from farmland soil-rhizosphere soil-plant. However, there is no significant correlation between groundwater and the other three matrices, indicating that infiltration from perchlorate contaminated farmland soil was not the predominant source for groundwater pollution in Chengdu. The perchlorate concentrations in the farmland soil and lettuce samples were significantly higher than those in the rhizosphere soil, primarily due to uptake of perchlorate through the rhizosphere micro-environment by lettuce, or accelerated degradation by rhizospheric microorganisms, which contributed more needs further investigation.

  20. Combination of minimal processing and irradiation to improve the microbiological safety of lettuce (Lactuca sativa, L.)

    International Nuclear Information System (INIS)

    Goularte, L.; Martins, C.G.; Morales-Aizpurua, I.C.; Destro, M.T.; Franco, B.D.G.M.; Vizeu, D.M.; Hutzler, B.W.; Landgraf, M.

    2004-01-01

    The feasibility of gamma radiation in combination with minimal processing (MP) to reduce the number of Salmonella spp. and Escherichia coli O157:H7 in iceberg lettuce (Lactuca sativa, L.) (shredded) was studied in order to increase the safety of the product. The reduction of the microbial population during the processing, the D 10 -values for Salmonella spp. and E. coli O157:H7 inoculated on shredded iceberg lettuce as well as the sensory evaluation of the irradiated product were evaluated. The immersion in chlorine (200 ppm) reduced coliform and aerobic mesophilic microorganisms by 0.9 and 2.7 log, respectively. D-values varied from 0.16 to 0.23 kGy for Salmonella spp. and from 0.11 to 0.12 kGy for E. coli O157:H7. Minimally processed iceberg lettuce exposed to 0.9 kGy does not show any change in sensory attributes. However, the texture of the vegetable was affected during the exposition to 1.1 kGy. The exposition of MP iceberg lettuce to 0.7 kGy reduced the population of Salmonella spp. by 4.0 log and E. coli by 6.8 log without impairing the sensory attributes. The combination of minimal process and gamma radiation to improve the safety of iceberg lettuce is feasible if good hygiene practices begins at farm stage

  1. Survival of Escherichia coli on Lettuce under Field Conditions Encountered in the Northeastern United States.

    Science.gov (United States)

    Weller, Daniel L; Kovac, Jasna; Roof, Sherry; Kent, David J; Tokman, Jeffrey I; Kowalcyk, Barbara; Oryang, David; Ivanek, Renata; Aceituno, Anna; Sroka, Christopher; Wiedmann, Martin

    2017-07-01

    Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval = 69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.

  2. Perception of bitterness, sweetness and liking of different genotypes of lettuce.

    Science.gov (United States)

    Chadwick, M; Gawthrop, F; Michelmore, R W; Wagstaff, C; Methven, L

    2016-04-15

    Lettuce is an important leafy vegetable, consumed across the world, containing bitter sesquiterpenoid lactone (SL) compounds that may negatively affect consumer acceptance and consumption. We assessed liking of samples with differing absolute abundance and different ratios of bitter:sweet compounds by analysing recombinant inbred lines (RILs) from an interspecific lettuce mapping population derived from a cross between a wild (L. serriola acc. UC96US23) and domesticated lettuce (L. sativa, cv. Salinas). We found that the ratio of bitter:sweet compounds was a key determinant of bitterness perception and liking. We were able to demonstrate that SLs, such as 8-deoxylactucin-15-sulphate, contribute most strongly to bitterness perception, whilst 15-p-hydroxylphenylacetyllactucin-8-sulphate does not contribute to bitter taste. Glucose was the sugar most highly correlated with sweetness perception. There is a genetic basis to the biochemical composition of lettuce. This information will be useful in lettuce breeding programmes in order to produce leaves with more favourable taste profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods.

    Science.gov (United States)

    Barbosa, Guilherme Lages; Gadelha, Francisca Daiane Almeida; Kublik, Natalya; Proctor, Alan; Reichelm, Lucas; Weissinger, Emily; Wohlleb, Gregory M; Halden, Rolf U

    2015-06-16

    The land, water, and energy requirements of hydroponics were compared to those of conventional agriculture by example of lettuce production in Yuma, Arizona, USA. Data were obtained from crop budgets and governmental agricultural statistics, and contrasted with theoretical data for hydroponic lettuce production derived by using engineering equations populated with literature values. Yields of lettuce per greenhouse unit (815 m2) of 41 ± 6.1 kg/m2/y had water and energy demands of 20 ± 3.8 L/kg/y and 90,000 ± 11,000 kJ/kg/y (±standard deviation), respectively. In comparison, conventional production yielded 3.9 ± 0.21 kg/m2/y of produce, with water and energy demands of 250 ± 25 L/kg/y and 1100 ± 75 kJ/kg/y, respectively. Hydroponics offered 11 ± 1.7 times higher yields but required 82 ± 11 times more energy compared to conventionally produced lettuce. To the authors' knowledge, this is the first quantitative comparison of conventional and hydroponic produce production by example of lettuce grown in the southwestern United States. It identified energy availability as a major factor in assessing the sustainability of hydroponics, and it points to water-scarce settings offering an abundance of renewable energy (e.g., from solar, geothermal, or wind power) as particularly attractive regions for hydroponic agriculture.

  4. Acidovorax valerianellae sp. nov., a novel pathogen of lamb's lettuce [Valerianella locusta (L.) Laterr].

    Science.gov (United States)

    Gardan, Louis; Stead, David E; Dauga, Catherine; Gillis, Moniek

    2003-05-01

    Bacterial spot disease of lamb's lettuce [Valerianella locusta (L.) Laterr.] was first observed in fields in 1991. This new bacterial disease is localized in western France in high-technology field production of lamb's lettuce for the preparation of ready-to-use salad. Nineteen strains isolated in 1992 and 1993 from typical black leaf spots of naturally infected lamb's lettuce were characterized and compared with reference strains of Acidovorax and Delftia. The pathogenicity of the 19 strains was confirmed by artificial inoculation. Biochemical and physiological tests, fatty acid profiles, DNA-DNA hybridization and other nucleic acid-based tests were performed. A numerical taxonomic analysis of the 19 lamb's lettuce strains showed a single homogeneous phenon closely related to previously described phytopathogenic taxa of the genus Acidovorax. DNA-DNA hybridization studies showed that the lamb's lettuce strains were 91-100% related to a representative strain, strain CFBP 4730(T), and constituted a discrete DNA hybridization group, indicating that they belong to the same novel species. Results from DNA-rRNA hybridization, 16S rRNA sequence analysis and fatty acid analysis studies confirmed that this novel species belongs to the beta-subclass of the Proteobacteria and, more specifically, to the family Comamonadaceae and the genus Acidovorax. The name Acidovorax valerianellae sp. nov. is proposed for this novel taxon of phytopathogenic bacteria. The type strain is strain CFBP 4730(T) (= NCPPB 4283(T)).

  5. Endophytic fungi occurring in fennel, lettuce, chicory, and celery--commercial crops in southern Italy.

    Science.gov (United States)

    D'Amico, Margherita; Frisullo, Salvatore; Cirulli, Matteo

    2008-01-01

    The occurrence of endophytic fungi in fennel, lettuce, chicory, and celery crops was investigated in southern Italy. A total of 186 symptomless plants was randomly collected and sampled at the stage of commercial ripeness. Fungal species of Acremonium, Alternaria, Fusarium, and Plectosporium were detected in all four crops; Plectosporium tabacinum was the most common in all crop species and surveyed sites. The effect of eight endophytic isolates (five belonging to Plectosporium tabacinum and three to three species of Acremonium) inoculated on lettuce plants grown in gnotobiosis was assessed by recording plant height, root length and dry weight, collar diameter, root necrosis, and leaf yellowing. P. tabacinum and three species of Acremonium, inoculated on gnotobiotically grown lettuce plants, showed pathogenic activity that varied with the fungal isolate. Lettuce plants inoculated with the isolates Ak of Acremonium kiliense, Ac of Acremonium cucurbitacearum, and P35 of P. tabacinum showed an increased root growth, compared to the non-inoculated control. The high frequency of P. tabacinum isolation recorded in lettuce plants collected in Bari and Metaponto, and in fennel plants from Foggia agricultural districts, suggests a relationship not only between a crop species and P. tabacinum, but also between the occurrence of the endophyte and the crop rotation history of the soil.

  6. Combination of minimal processing and irradiation to improve the microbiological safety of lettuce (Lactuca sativa, L.)

    Energy Technology Data Exchange (ETDEWEB)

    Goularte, L.; Martins, C.G.; Morales-Aizpurua, I.C.; Destro, M.T.; Franco, B.D.G.M.; Vizeu, D.M.; Hutzler, B.W.; Landgraf, M. E-mail: landgraf@usp.br

    2004-10-01

    The feasibility of gamma radiation in combination with minimal processing (MP) to reduce the number of Salmonella spp. and Escherichia coli O157:H7 in iceberg lettuce (Lactuca sativa, L.) (shredded) was studied in order to increase the safety of the product. The reduction of the microbial population during the processing, the D{sub 10}-values for Salmonella spp. and E. coli O157:H7 inoculated on shredded iceberg lettuce as well as the sensory evaluation of the irradiated product were evaluated. The immersion in chlorine (200 ppm) reduced coliform and aerobic mesophilic microorganisms by 0.9 and 2.7 log, respectively. D-values varied from 0.16 to 0.23 kGy for Salmonella spp. and from 0.11 to 0.12 kGy for E. coli O157:H7. Minimally processed iceberg lettuce exposed to 0.9 kGy does not show any change in sensory attributes. However, the texture of the vegetable was affected during the exposition to 1.1 kGy. The exposition of MP iceberg lettuce to 0.7 kGy reduced the population of Salmonella spp. by 4.0 log and E. coli by 6.8 log without impairing the sensory attributes. The combination of minimal process and gamma radiation to improve the safety of iceberg lettuce is feasible if good hygiene practices begins at farm stage.

  7. Evaluation of respiratory parameters in minimally processed lettuce grown under organic or conventional system

    Directory of Open Access Journals (Sweden)

    Júlio César Mello

    2010-12-01

    Full Text Available The increased preference for minimally processed vegetables has been attributed to the health benefits associated with fresh produce and the demand for ready-to-eat salads. In this paper, lettuce (Lactuca sativa L. was evaluated for the effects of different cropping systems on the respiratory properties. Lettuce was packaged in low density polyethylene bags and stored in a refrigerator at 4 ºC. The concentration of carbon dioxide and oxygen inside the package was monitored during the storage at zero, three, six, eight, ten and twelve days by gas chromatography. Dry matter variation was measured gravimetrically up to day fourteen of storage. Values of respiratory rate for conventional lettuce increased from day 1 to 3 and remained low, while respiratory rate of the organic lettuce increased three-fold up to day 8, stabilizing at a high level. Variation in dry matter during storage also resulted from differences between the two cultivation systems. The highest content of dry matter was achieved by organic lettuce.

  8. The Protective Role of Lettuce oil (Lactuca sativa) against Radiation induced Biological Hazards in Male Rats

    International Nuclear Information System (INIS)

    Abdel-Magied, N.; Ahmed, A.G.

    2011-01-01

    This study was conducted to clarify the potential role of lettuce oil against damages induced in rats due to exposure to gamma radiation. Adult male albino rats (120-150 g) were divided into 4 groups each of 12 animals. The first group was considered control animals. The second group received, via gavages, lettuce oil (200 mg/Kg body weight) for 3 weeks. The third group was subjected to a single dose of 6.5Gy whole body gamma irradiation. The fourth group received lettuce oil for 3 weeks then was exposed to radiation. Blood samples were collected 1 and 7 days post irradiation. Exposure of rats to gamma irradiation caused a significant increase in the level of glucose, total cholesterol (TC), triglycerides (TG), malondialdehyde (MDA) and follicle stimulating hormone (FSH) while a significant decrease was recorded in glutathione content (GSH), superoxide dismutase (SOD) and catalase activities, white blood cells (WBCs), red blood cells (RBCs), haemoglobin content (Hb), haematocrit percentage (Hct%), mean corpuscular volume (MCV), platelets (PLT), leutinizing hormone (LH) and testosterone hormone . In rats treated with lettuce oil then exposed to radiation, the results showed an improvement in all previous parameters. It could be concluded that lettuce oil might reduce the biological hazards in rats induced by gamma irradiation

  9. Combination of minimal processing and irradiation to improve the microbiological safety of lettuce ( Lactuca sativa, L.)

    Science.gov (United States)

    Goularte, L.; Martins, C. G.; Morales-Aizpurúa, I. C.; Destro, M. T.; Franco, B. D. G. M.; Vizeu, D. M.; Hutzler, B. W.; Landgraf, M.

    2004-09-01

    The feasibility of gamma radiation in combination with minimal processing (MP) to reduce the number of Salmonella spp. and Escherichia coli O157:H7 in iceberg lettuce ( Lactuca sativa, L.) (shredded) was studied in order to increase the safety of the product. The reduction of the microbial population during the processing, the D10-values for Salmonella spp. and E. coli O157:H7 inoculated on shredded iceberg lettuce as well as the sensory evaluation of the irradiated product were evaluated. The immersion in chlorine (200 ppm) reduced coliform and aerobic mesophilic microorganisms by 0.9 and 2.7 log, respectively. D-values varied from 0.16 to 0.23 kGy for Salmonella spp. and from 0.11 to 0.12 kGy for E. coli O157:H7. Minimally processed iceberg lettuce exposed to 0.9 kGy does not show any change in sensory attributes. However, the texture of the vegetable was affected during the exposition to 1.1 kGy. The exposition of MP iceberg lettuce to 0.7 kGy reduced the population of Salmonella spp. by 4.0 log and E. coli by 6.8 log without impairing the sensory attributes. The combination of minimal process and gamma radiation to improve the safety of iceberg lettuce is feasible if good hygiene practices begins at farm stage.

  10. Fertilization effect on yield and nitrate content in organically produced lettuce

    Directory of Open Access Journals (Sweden)

    Čabilovski Ranko

    2010-01-01

    Full Text Available The effect of applying different organic materials (OM on yield and nitrate content in lettuce was studied in a field experiment on a farm registered for organic production during two years (2007 and 2008. Treatments were: farmyard manure (ST, guano (G, milled soybean (Glicine hispida seed (S; milled forage pea (Pisum sativum seed (P and control treatment (q. Biannual average fresh matter (FM yield of lettuce on fertilized plots ranges from 45.44 t ha-1 (P to 46,38 t ha-1 (ST and was significantly higher than fresh matter yield of the control (39.34 t ha-1, while the differences between fertilized treatments were not significant. Nitrate content in the fresh mass of lettuce in all treatments in both years was below the maximum allowed content (2.500 mg kg-1 regulated by the EU (Commission Regulation (EC, No 466/2001. In both years, the lowest nitrate content in the fresh mass of lettuce was recorded with the control treatment (q and highest with S treatment. Nitrate contents with G, P and S treatments were significantly higher than that recorded with FYM and q, whereas the differences between FYM and q were not significant in either the first or the second year of research. Linear correlation (r = 0.83**in 2007; r = 0.91** in 2008 was found between the content of mineral N in the soil and nitrate content in the FM of lettuce at the moment of harvesting in both years. .

  11. Efficient and stable transformation of Lactuca sativa L. cv. Cisco (lettuce) plastids.

    Science.gov (United States)

    Kanamoto, Hirosuke; Yamashita, Atsushi; Asao, Hiroshi; Okumura, Satoru; Takase, Hisabumi; Hattori, Masahira; Yokota, Akiho; Tomizawa, Ken-Ichi

    2006-04-01

    Transgenic plastids offer unique advantages in plant biotechnology, including high-level foreign protein expression. However, broad application of plastid genome engineering in biotechnology has been largely hampered by the lack of plastid transformation systems for major crops. Here we describe the development of a plastid transformation system for lettuce, Lactuca sativa L. cv. Cisco. The transforming DNA carries a spectinomycin-resistance gene (aadA) under the control of lettuce chloroplast regulatory expression elements, flanked by two adjacent lettuce plastid genome sequences allowing its targeted insertion between the rbcL and accD genes. On average, we obtained 1 transplastomic lettuce plant per bombardment. We show that lettuce leaf chloroplasts can express transgene-encoded GFP to approximately 36% of the total soluble protein. All transplastomic T0 plants were fertile and the T1 progeny uniformly showed stability of the transgene in the chloroplast genome. This system will open up new possibilities for the efficient production of edible vaccines, pharmaceuticals, and antibodies in plants.

  12. iTRAQ-based proteomics of sunflower cultivars differing in resistance to parasitic weed Orobanche cumana.

    Science.gov (United States)

    Yang, Chong; Xu, Ling; Zhang, Na; Islam, Faisal; Song, Wenjian; Hu, Luyang; Liu, Dan; Xie, Xiaonan; Zhou, Weijun

    2017-07-01

    Orobanche cumana is an obligate root parasite causing severe damage to many economically important crops, including sunflowers worldwide. For efficient control measures, it is necessary to understand the resistant mechanism during interaction at molecular level. The present study emphasizes on comparative proteomics to investigate the mechanistic basis of compatible and incompatible interaction of O. cumana with resistant (JY207) and susceptible (TK0409) sunflowers. More than 3500 proteins were identified from two cultivars by iTRAQ analysis. Identified proteins associated with general functions, posttranslational modification, energy production and conversion, carbohydrate transport and metabolism, and signal transduction mechanisms were the most represented category of induced proteins in both cultivars. The resistant interaction was characterized by alteration of defense-related proteins involved in recognition of parasites, accumulation of pathogenesis-related proteins, biosynthesis of lignin, and detoxification of toxic metabolites in JY207 after inoculation. The susceptible interaction was characterized by decreased abundance of proteins involved in biosynthesis and signaling of plant growth regulators including auxin, gibberellin, brassinosteroid, and ethylene in TK0409 after inoculation. The present study provides comprehensive details of proteins and differential modulation of pathways regulated under compatible and incompatible interaction, allowing the identification of important molecular components for development of sustainable resistance against this parasite. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Growth of Verticillium longisporum in Xylem Sap of Brassica napus is Independent from Cultivar Resistance but Promoted by Plant Aging.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-09-01

    As Verticillium stem striping of oilseed rape (OSR), a vascular disease caused by Verticillium longisporum, is extending into new geographic regions and no control with fungicides exists, the demand for understanding mechanisms of quantitative resistance increases. Because V. longisporum is strictly limited to the xylem and resistance is expressed in the systemic stage post root invasion, we investigated a potential antifungal role of soluble constituents and nutritional conditions in xylem sap as determinants of cultivar resistance of OSR to V. longisporum. Assessment of biometric and molecular genetic parameters applied to describe V. longisporum resistance (net area under disease progress curve, stunting, stem thickness, plant biomass, and V. longisporum DNA content) showed consistent susceptibility of cultivar 'Falcon' in contrast to two resistant genotypes, 'SEM' and 'Aviso'. Spectrophotometric analysis revealed a consistently stronger in vitro growth of V. longisporum in xylem sap extracted from OSR compared with the water control. Further comparisons of fungal growth in xylem sap of different cultivars revealed the absence of constitutive or V. longisporum induced antifungal activity in the xylem sap of resistant versus susceptible genotypes. The similar growth of V. longisporum in xylem sap, irrespective of cultivar, infection with V. longisporum and xylem sap filtration, was correlated with about equal amounts of total soluble proteins in xylem sap from these treatments. Interestingly, compared with younger plants, xylem sap from older plants induced significantly stronger fungal growth. Growth enhancement of V. longisporum in xylem sap of aging plants was reflected by increased contents of carbohydrates, which was consistent in mock or V. longisporum-infected plants and independent from cultivar resistance. The improved nutritional conditions in the xylem of more mature plants may explain the late appearance of disease symptoms, which are observed only in

  14. In-package inhibition of E.coli 0157:H7 on bulk romaine lettuce using cold plasma

    Science.gov (United States)

    Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of Escherichia coli O157:H7, surface morphology, color, carbon dioxide generation, and weight loss of bulk Romaine lettuce in a commercial plastic clamshell container. The lettuce samples were pa...

  15. Assessment of Escherichia coli O157:H7 transference from soil to Iceberg Lettuce via a contaminated harvesting knife

    Science.gov (United States)

    The potential for coring knives to cross-contaminate lettuce heads with pathogens was evaluated for both ring and blade ends. Rings and blades artificially contaminated with Escherichia coli O157:H7 (EHEC), were used to core three successive heads of iceberg lettuce. The coring rings and blades were...

  16. Discrimination methods of biological contamination on fresh-cut lettuce based on VNIR and NIR hyperspectral imaging

    Science.gov (United States)

    Multispectral imaging algorithms were developed using visible-near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging (HSI) techniques to detect worms on fresh-cut lettuce. The optimal wavebands that detect worm on fresh-cut lettuce for each type of HSI were investigated using the one-way...

  17. Effector-mediated discovery of a novel resistance gene against Bremia Lactucae in a nonhost lettuce species

    NARCIS (Netherlands)

    Giesbers, A.K.J.; Pelgrom, Alexandra; Visser, R.G.F.; Niks, R.E.; Ackerveken, Van Den Guido; Jeuken, M.J.W.

    2017-01-01

    Candidate effectors from lettuce downy mildew (Bremia lactucae) enable high-throughput germplasm screening for the presence of resistance (R) genes. The nonhost species Lactuca saligna comprises a source of B. lactucae R genes that has hardly been exploited in lettuce breeding. Its

  18. Effector-mediated discovery of a novel resistance gene against Bremia lactucae in a nonhost lettuce species

    NARCIS (Netherlands)

    Giesbers, Anne K J; Pelgrom, Alexandra J E; Visser, Richard G F; Niks, Rients E; Van den Ackerveken, Guido; Jeuken, Marieke J W

    2017-01-01

    Candidate effectors from lettuce downy mildew (Bremia lactucae) enable high-throughput germplasm screening for the presence of resistance (R) genes. The nonhost species Lactuca saligna comprises a source of B. lactucae R genes that has hardly been exploited in lettuce breeding. Its

  19. Effects of pre-and postharvest lighting on quality and shelf life of fresh-cut lettuce

    NARCIS (Netherlands)

    Woltering, E.J.; Witkowska, I.M.

    2016-01-01

    The effects of pre-and postharvest lighting on quality and shelf life of fresh-cut lettuce was investigated. Lettuce was grown under different light intensities (120 and 250 μmol m-2 s-1 PAR from fluorescent tubes) and quality at harvest and subsequent postharvest

  20. Application of chlorophyll fluorescence imaging and hyperspectral imaging in evaluation of decay in fresh-cut lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is commercially the most popular leafy vegetable whose leaves are usually consumed raw. Cleaned, cored, and chopped (fresh-cut) lettuce is a desirable, but highly perishable product. Modified atmosphere packaging (MAP) has been introduced to maintain quality of fresh-cut ...