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Germplasm Line (germplasm + line)
Selected AbstractsComparative evaluation of exotic and adapted germplasm of spring wheat for floral characteristics in the Indo-Gangetic Plains of northern IndiaPLANT BREEDING, Issue 6 2007S. K. Singh Abstract Four hundred spring wheat genotypes, comprising exotic and indigenous germplasm and adapted cultivars for commercial cultivation, were investigated during four crop seasons for six floral characteristics related to outcrossing behaviour. Genetic variability and heritability were investigated along with phenotypic correlation coefficients among these characteristics. A significant quantitative variation existed among the characteristics in all three groups. High heritability for stigma length, openness of florets, anther extrusion and duration of floral opening indicated that selection for these characteristics may be effective. The adapted cultivars were found more promising than the exotic and indigenous germplasm. Most of the characteristics showed significantly positive correlation with each other and high correlation was observed between anther and stigma length, and anther extrusion and duration of floral opening. Superiority of varietal mixtures and segregating generations (F3 and F4) of two crosses over parental lines suggested that heterozygosity and heterogeneity can provide yield advantages. Germplasm lines possessing superior expression of floral characteristics may be used to improve yielding ability through enhanced heterozygosity or the development of hybrids. [source] Genetic Diversity of Landraces in Gossypium arboreum L. Race sinense Assessed with Simple Sequence Repeat MarkersJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2006Wang-Zhen Guo Abstract Asiatic cotton (Gossypium arboreum L.) is an "Old World" cultivated cotton species, the sinense race of which is planted extensively in China. This species is still used in the current tetraploid cotton breeding program as an elite germplasm line, and is also used as a model for genomic research in Gossypium. In the present study, 60 cotton microsatellite markers, averaging 4.6 markers for each A-genome chromosome, were chosen to assess the genetic diversity of 109 accessions. These included 106 G. arboreum landraces, collected from 18 provinces throughout four Asiatic cotton-growing regions in China. A total of 128 alleles were detected, with an average of 2.13 alleles per locus. The largest number of alleles, as well as the maximum number of polymorphic loci, was detected in the A03 linkage group. No polymorphic alleles were detected on chromosome 10. The polymorphism information content for the 22 polymorphic microsatellite loci varied from 0.52 to 0.98, with an average of 0.89. Genetic diversity analysis revealed that the landraces in the Southern region had more genetic variability than those from the other two regions, and no significant difference was detected between landraces in the Yangtze and the Yellow River Valley regions. These findings are consistent with the history of sinense introduction, with the Southern region being the presumed center of origin for Chinese Asiatic cotton, and with subsequent northeastward extension to the Yangtze and Yellow River Valleys. Cluster analysis, based on simple sequence repeat data for 60 microsatellite loci, clearly differentiated Vietnamese and G. herbaceum landraces from the sinense landrace. No relationship between inter-variety similarity and geographical ecological region was observed. The present findings indicate that the Southern region landraces may have been directly introduced into the provinces in the middle and lower Yangtze River Valley, where Asiatic cotton was most extensively grown, and further race sinense crops were subsequently produced. (Managing editor: Ya-Qin Han) [source] A melatonin-rich germplasm line of St John's wort (Hypericum perforatum L.)JOURNAL OF PINEAL RESEARCH, Issue 3 2006Susan J. Murch Abstract:, The objective of this study was to evaluate the possibility of selecting genetic variants of plants with enhanced concentrations of the indoleamine melatonin. A germplasm line of the medicinal plant species, St John's wort (Hypericum perforatum L.), with high levels of melatonin was selected in vitro using mutagenized tissues. The germplasm line has remained stable over a 5-yr period and contained >12-fold (1200%) melatonin content compared with the wild-type plant. Melatonin is a ubiquitous, highly conserved molecule with known therapeutic roles in the treatment of sleep disorders, depression, aging, inhibition of cancer cell growth and as a free radical scavenger and antioxidant. The selected melatonin-rich germplasm line of St John's wort may facilitate fundamental studies on melatonin biosynthesis, metabolism and new developments in natural products for treatment of human diseases. [source] Variability and divergence in Pongamia pinnata (L.) Pierre germplasm , a candidate tree for biodieselGCB BIOENERGY, Issue 6 2009N. SUNIL Abstract Three explorations were undertaken in South East Coastal zone of India covering parts of Andhra Pradesh (AP) and Orissa states to collect Pongamia pinnata (L.) Pierre germplasm during March,June 2007. A total of 123 accessions were collected and seed data recorded were analyzed for morphometric traits viz., seed length, seed width, seed thickness, 100-seed weight and oil content. Variation in the collected germplasm was analyzed using anova, simple measures of variation and D2 statistics. Significant genetic variability between seed traits and oil content and association among the seed traits was recorded. Phenotypic variance was higher than genotypic variance for all the characters indicating dominant role of environment. High heritability (broad sense) for 100-seed weight (97.6%) and oil content (86.7%) indicated the reliability of these characters as selection criteria for plus trees. Genetic gain was maximum for 100-seed weight (62.6%) followed by oil content (30.5%). D2 analysis grouped the accessions into 12 clusters. Cluster XII and cluster IX were the most diverse based on the intercluster distance. Based on the observed diversity, Chittoor, Srikakulam and Adilabad districts of AP are most suitable for collecting diverse germplasm lines and also for in situ conservation. [source] Characterization of chickpea differentials for pathogenicity assay of ascochyta blight and identification of chickpea accessions resistant to Didymella rabieiPLANT PATHOLOGY, Issue 6 2004W. Chen Forty-eight chickpea germplasm lines, including 22 differentials used in previous studies, were characterized for disease phenotypes following inoculation with six isolates of Didymella (anamorph Ascochyta) rabiei, representing a wide spectrum of pathogenic variation. Representative isolates were also directly compared with six previously identified races on eight chickpea genotypes. Many of the chickpea differentials reacted similarly to inoculation with each isolate of D. rabiei, and several previously identified races caused similar levels of disease on the differentials. This indicates that the number of differentials can be reduced significantly without sacrificing accuracy in describing pathogenic variation of D. rabiei on chickpea. Pathogenic variation among samples of US isolates allowed classification of the isolates into two pathotypes. The distribution of disease phenotypes of the 48 germplasm lines was bimodal after inoculation with pathotype I isolates, whereas the distribution of disease phenotypes was continuous after inoculation with pathotype II isolates. Such distinct distribution patterns suggest that chickpea plants employ different resistance mechanisms to each pathotype and that the two pathotypes may have different genetic mechanisms controlling pathogenicity. The advantages of using the two-pathotype system in assaying pathogenicity of the pathogen and in studying resistance mechanisms of the host are discussed. Three chickpea accessions, PI 559361, PI 559363 and W6 22589, showed a high level of resistance to both pathotypes, and can be employed as resistance sources in chickpea breeding programmes for resistance to ascochyta blight. [source] | ||||||||||