Munguía-Rosas, Miguel A; Campos-Navarrete, María J; Parra-Tabla, Víctor
Dimorphic cleistogamy is a specialized form of mixed mating system where a single plant produces both open, potentially outcrossed chasmogamous (CH) and closed, obligately self-pollinated cleistogamous (CL) flowers. Typically, CH flowers and seeds are bigger and energetically more costly than those of CL. Although the effects of inbreeding and floral dimorphism are critical to understanding the evolution and maintenance of cleistogamy, these effects have been repeatedly confounded. In an attempt to separate these effects, we compared the performance of progeny derived from the two floral morphs while controlling for the source of pollen. That is, flower type and pollen source effects were assessed by comparing the performance of progeny derived from selfed CH vs. CL and outcrossed CH vs. selfed CH flowers, respectively. The experiment was carried out with the herb Ruellia nudiflora under two contrasting light environments. Outcrossed progeny generally performed better than selfed progeny. However, inbreeding depression ranges from low (1%) to moderate (36%), with the greatest value detected under shaded conditions when cumulative fitness was used. Although flower type generally had less of an effect on progeny performance than pollen source did, the progeny derived from selfed CH flowers largely outperformed the progeny from CL flowers, but only under shaded conditions and when cumulative fitness was taken into account. On the other hand, the source of pollen and flower type influenced seed predation, with selfed CH progeny the most heavily attacked by predators. Therefore, the effects of pollen source and flower type are environment-dependant and seed predators may increase the genetic differences between progeny derived from CH and CL flowers. Inbreeding depression alone cannot account for the maintenance of a mixed mating system in R. nudiflora and other unidentified mechanisms must thus be involved. PMID:24260515
Dry dormant seeds of mungbean (Vigna radiata (L) Wilczek) were treated with gamma rays (15, 30 and 60 kR). The serrated leaf mutation was noticed in M2 of cultivar Pak 32 treated with 60 kR. Cf 14 plants, 3 showed the altered leaf structure and the others were normal. The feature of this mutant was the deep serration of leaflet margins. The mutant had large thick leaflets with prominent venation. The mutant bred true in the M3 and successive generation. Details of the morphological characteristics of the mutant are presented. The mutant exhibited slower growth particularly during the early stages of development, flowered later and attained shorter height. There was an increase in the number of pods, in seed weight and in seed protein content, but number of seed per pod was considerably reduced. The seed coat colour showed a change from green to yellowish green. In the mutant's flowers the stamina were placed much below the stigma level and the stigma sometimes protruded the corolla. Outcrossing of 4% recorded in some of the mutant lines revealed a reduced cleistogamy. The low number of seeds per pod in the mutant could be due to reduced pollen fertility. The mutant behaved as monogenic recessive. The symbols SL/sl are proposed for this allelic pair. The mutant may have use as a green manure crop because of its large foliage and for the breeders as a genetic marker
Full Text Available Ergot is a disease of cereals and grasses caused by fungi in the genus Claviceps. Of particular concern are Claviceps purpurea in temperate regions, C. africana in sorghum (worldwide, and C. fusiformis in pearl millet (Africa, Asia. The fungi infect young, usually unfertilized ovaries, replacing the seeds by dark mycelial masses known as sclerotia. The percentage of sclerotia in marketable grain is strictly regulated in many countries. In winter rye, ergot has been known in Europe since the early Middle Ages. The alkaloids produced by the fungus severely affect the health of humans and warm-blooded animals. In sorghum and pearl millet, ergot became a problem when growers adopted hybrid technology, which increased host susceptibility. Plant traits reducing ergot infection include immediate pollination of receptive stigmas, closed flowering (cleistogamy, and physiological resistance. Genetic, nonpollen-mediated variation in ergot susceptibility could be demonstrated in all three affected cereals. Fungicides have limited efficacy and application is weather dependent. Sorting out the sclerotia from the harvest by photocells is expensive and time consuming. In conclusion, molecular-based hybrid rye breeding could improve pollen fertility by introgressing effective restorer genes thus bringing down the ergot infection level to that of conventional population cultivars. A further reduction might be feasible in the future by selecting more resistant germplasm.
Bateman, Richard M; Sramkó, Gábor; Rudall, Paula J
migration route that may have begun in East Asia before passing through North America and presumably Greenland. The incohesive pollinia, rapidly desiccating anther locules, weakly developed rostellum, exceptionally adhesive stigma and the close juxtaposition of compact male and female reproductive organs together conspire to cause routine autogamy and frequent cleistogamy, despite the continued production of substantial nectar reservoirs in the spur and consequent ongoing attraction to the flowers of insects, including mosquitoes. When considered in combination with independently derived lineages of Platanthera on the Azorean and Hawaiian archipelagos also bearing small green flowers, our observations show allometric and paedomorphic reductions in flower size as the primary evolutionary driver, but also indicate strong developmental and functional constraints. PMID:25893148
Richard M. Bateman
represents the terminus of a migration route that may have begun in East Asia before passing through North America and presumably Greenland. The incohesive pollinia, rapidly desiccating anther locules, weakly developed rostellum, exceptionally adhesive stigma and the close juxtaposition of compact male and female reproductive organs together conspire to cause routine autogamy and frequent cleistogamy, despite the continued production of substantial nectar reservoirs in the spur and consequent ongoing attraction to the flowers of insects, including mosquitoes. When considered in combination with independently derived lineages of Platanthera on the Azorean and Hawaiian archipelagos also bearing small green flowers, our observations show allometric and paedomorphic reductions in flower size as the primary evolutionary driver, but also indicate strong developmental and functional constraints.
杨霞; 王丹; 张猛
P/O of three varieties of Feijoa sellowiana was accounted and breeding systems class was defined;pollens of three varieties of F. selloiviana were observed with scanning electron microscope; and the morphology and taxono-my significance of the pollens were analyzed. The results showed that P/O of 'Coolidge', 'Mammoth' and 'Unique' were 6 ± 2. 37、4. 41 ± 1. 47 and 8. 52±2. 84 and the breeding systems was cleistogamy;Feijoa pollen was radial sym-metry; polar view of the pollens was approximately equilateral triangle, with a clear tricolporate (syncolpate) and go-niotreme; equatorial view of the pollens appears oval; the surface of the pollens had granulated sculpture. At the same time, the morphology of the three varieties was also slightly different, but not obvious. Compared with other four ge-nus of the same family, the pollen morphology of Feijoa was in accordance with the main features of Myrtaceae plant and had important taxonomy significance.%利用扫描电子显微镜对费约果三个品种的花粉粒显微结构形态进行观察,计算三个品种费约果的花粉-胚珠比,并据此分析费约果的形态特征和分类学意义,划分其繁育系统类型.结果表明:‘Coolidge ’、‘Mammoth’和‘Unique’三个品种的花粉-胚珠比分别为6±2.37、4.41±1.47和8.52±2.84,其繁育系统为闭花受精型；费约果花粉粒呈辐射对称,极面观近似等边三角形,有明显的三孔沟(合沟),具角萌发孔,其赤道面观为椭圆形,花粉粒表面具颗粒状雕纹；三个品种花粉粒形态相比之下也略有差异,但不明显.从费约果与同科4个属花粉粒的对比中可以得出,费约果花粉粒形态结构符合桃金娘科植物的主要特征,其花粉粒形态在分类学上具有重要意义.
Radu E. SESTRAS
Full Text Available Following the proposal of Academic Council of Horticulture Faculty, the Senate of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca accepted nominee Professor Jules Janick for Doctor Honoris Causa award. The title was awarded in festive ceremony on September 30, 2010. Jules Janick, Professor at Purdue University has a long and distinguished career devoted to horticulture in all its facets. In horticultural research, he has made important advances including the genetics of sex determination including the synthesis of heteromorphic sex chromosomes, fireblight resistance, cleistogamy, cucurbitacins, artemisisin production, anthocyanin pigmentation, as well as in vitro metabolite production from somatic embryos and the production of synthetic seed. In crop improvement, he has been associated with the release of 21 scab-resistant apple cultivars, three pear cultivars with tolerance to fireblight, delayed-bolting arugula, crack resistant tomato, and the first release of a pelargonium cultivar from somaclonal variation. Professor Janick has made contributions to the historical aspects of horticulture and explored the relation of art and horticultural technology with special studies on the iconography of Rubus, Cucurbitaceae, and Solanaceae, opening up a new approach to the study of plant diversity, origins, cultivar evolution, and diversity. Professor Janick has been a prolific author and editor in horticulture. He was the editor of HortScience and editor of the Journal of ASHS. He is the founder and editor of both Horticultural Reviews and Plant Breeding Reviews. Since 2002 he has been the science editor of Chronica Horticulturae (ISHS. Janick has edited and produced six proceedings of New Crops symposia since 1990 that have had a deep impact on new crop information. The development of a new crop website has become a major world resource for information on crops. He is the author of the texts Horticultural Science, Plant Science