scholarly journals Studies On Natural Cross-Pollination In Pigeonpeas (Cajanus cajan)

Author(s):  
Raul Abrams

Results obtained in a study of natural crossing among strains of pigeonpea grown in adjacent rows show that cross-pollination ranges from 5.47 to 6.33 with an average of 5.80 percent in a population of 5,328 plants. Progenies from plants artificially selfed with nylon bags produced no natural hybrids. The results obtained in this study indicate that, for the maintenance of pure varieties or stocks, and the seed production of new varieties, they should be grown under isolation, or with the flowerbuds covered with finely woven nylon bags, in order to prevent contamination.

1976 ◽  
Vol 86 (1) ◽  
pp. 205-209 ◽  
Author(s):  
M. A. Elfawal ◽  
M. A. Bishr ◽  
E. K. Hassoub

SUMMARYThe percentage of natural cross pollination was estimated in the Alexandria area (Egypt) in two sites near and far from an apiary. The Egyptian cotton variety Giza 45 and the glandless strain Bahtim 110, as a marker parent, were used during three growing seasons. The average natural crossing within the square of the marker parent were 3·54 and 0·34% near and far from the apiary respectively. For the plants around the square of pollen source, however, the average of natural crossing was 0·56% near the apiary, while it was 0·21% far from the apiary. The natural crossing steadily decreased as the distance from the marker variety increased.


Author(s):  
Rafat Sultana and K.B. Saxena

Natural cross-pollination in pigeonpea, mediated by insects, is a universal phenomenon with the first report appearing in 1919. Considerable information is now available on various aspects of this biological phenomenon including degree of out-crossing and pollinating agents in different parts of the world. A large variation (0-60%) has been recorded in 30 different environments across 11 countries. The role of cross-pollination in rapid deterioration of the genetic purity of cultivars and elite genetic stocks is well understood and documented by breeders and seed producers. Pigeonpea breeders have converted this constraint into an opportunity by way of visually selecting natural hybrids from landraces in farmers’ fields and deriving high yielding cultivars. In a key development, the occurrence of natural cross-pollination in the wild relatives of pigeonpea has also been recorded; and in three wild species such natural hybrids have yielded valuable cytoplasmic male sterility systems. This has encouraged breeders to develop a hybrid breeding technology with natural out-crossing playing a key role in the large-scale seed production of commercial pigeonpea hybrids.


Author(s):  
T.M. Seredin ◽  
◽  
A.F. Agafonov ◽  

the article summarizes the long-term research on the selection and seed production of onion crops of the Federal Scientific Center of Vegetable Growing. The prospects of using new varieties to obtain high-quality products for different zones are shown.


2021 ◽  
pp. 15-23
Author(s):  
V. F. Pivovarov ◽  
A. V. Soldatenko ◽  
O. N. Pyshnaya ◽  
L. K. Gurkina

The article reflects the issues of the current state of scientific research at the FSBSI FSVC, shows the directions and prospects for the development of selection and seed production of vegetable crops. The main mission of the selection and seed-growing work of the FSVC is the creation and reproduction of varieties and hybrids of vegetable and melon crops of a new generation, characterized by resistance to abiotic and biotic stressors, high productivity and product quality. One of the main ways to increase the efficiency of the breeding process is the use of modern methods of biotechnology and molecular genetics, which make it possible to obtain new genotypes and reduce the time of breeding. Success has been achieved in the creation of homozygous lines of cabbage, squash, cucumber, carrots. For the first time, it was possible to complete a full cycle of obtaining doubled radish haploids in microspore culture in vitro. The institution pays special attention to immunological research on the resistance of crops and new varieties to diseases, as well as protecting plants from pests and diseases. Phytosanitary monitoring, assessment and selection of resistant genotypes are carried every years. One of the important theoretical and practical problems solved at the institution is the development of environmentally friendly products based on preparations obtained from plants with a high content of biologically active compounds with adaptogenic properties. In the center, a new direction of research in traditional breeding has received significant development - the creation of varieties of vegetable plants with an increased content of biologically active substances and antioxidants, on the basis of which functional products are created. The persistence of modern varieties and hybrids of table carrots, depending on the biochemical composition, has been studied. Methods for enriching vegetable plants with micronutrients are being developed. A large amount of scientific research is being carried out on the development of technologies for the cultivation of new varieties and hybrids, as well as technologies for their seed production. At the branches located in different soil and climatic conditions, hospitals were established to study the interaction of factors controlling soil fertility and the productivity of vegetable crops in agrocenoses (crop rotation, soil treatment systems, fertilizers and plant protection). In general, at the FSBSI FSVC, all research is aimed at developing and improving methods in breeding and seed production of vegetable crops, creating new breeding achievements and developing varietal technologies for their cultivation.


1965 ◽  
Vol 16 (4) ◽  
pp. 533 ◽  
Author(s):  
AJ Pritchard

An albino seedling character in Sorghum almum Parodi was shown to be tetrasomically inherited. Segregation ratios for a pale green seedling character were very variable, and it is probable that more than one gene is involved. With the albino seedling character as a marker gene, it was found that the average natural crossing in S. almum was approximately 54% at one location and 70% at another. The maximum natural crossing between S. almum and S. halepense (L.) Pers. was 57%, but the mean was only 20%. This may indicate that some S. almum plants exhibit a degree of genetic isolation from S. halepense when these species are grown together under natural conditions.


2003 ◽  
Vol 2 (2) ◽  
pp. 133-138 ◽  
Author(s):  
Jeffery D. Ray ◽  
Thomas C. Kilen ◽  
Craig A. Abel ◽  
Robert L. Paris

1984 ◽  
Vol 64 (1) ◽  
pp. 43-46 ◽  
Author(s):  
P. B. E. McVETTY ◽  
J. NUGENT-RIGBY

Four populations of faba beans (Vicia faba L.) consisting of the black-spot-flowered varieties, Ackerperle, Diana, Herz Freya and UMFB-22, each combined with the white flowered variety, Triple White, were grown at three locations in each of 2 yr. The extent of natural cross pollination was estimated from a subsequent year’s grow-out of the Triple White test seed. The extent of natural cross pollination differed for varieties, locations and years, with years being the most significant. The year effect was probably due to different environmental stresses on the faba beans.Key words: Vicia faba, fertilization


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