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Parental Combinations (parental + combination)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Molecular data reveal that the tetraploid Tragopogon kashmirianus (Asteraceae: Lactuceae) is distinct from the North American T. mirus

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2008
EVGENY V. MAVRODIEV
Tragopogon kashmirianus (Asteraceae: Lactuceae) (2n = 24) was described based on collections from Kashmir. The tetraploid is morphologically similar to allotetraploid T. mirus from North America that has formed in western North America from the introduced T. dubius (2n = 12) and T. porrifolius (salsify; 2n = 12). Singh and Kachroo (1976) suggested that T. kashmirianus might have formed from the same diploid parental combination as T. mirus. To determine this, we investigated internal and external transcribed spacers (ITS, ETS) and five plastid regions of T. kashmirianus and species reported from Kashmir, northern India and neighbouring countries (T. badachschanicus, T. longirostris, T. porrifolius, T. pratensis, T. orientalis, T. subalpinus, T. trachycarpus, T. gracilis and T. dubius). Molecular data indicate that the parents of T. kashmirianus are not the European T. porrifolius and T. dubius. The exact parentage of T. kashmirianus is still unclear, but if it is an allotetraploid, at least one parent is a species native to Kashmir/India. Alternatively, it may represent an autopolyploid, again with the diploid parent native to Kashmir/India. We also found that ,T. dubius' from Kashmir is phylogenetically and morphologically distinct from collections of T. dubius from Europe and probably represents a previously unrecognized species. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 391,398. [source]

Diversity in phenotypic and nutritional traits in vegetable amaranth (Amaranthus tricolor), a nutritionally underutilised crop

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2010
Sudhir Shukla
Abstract BACKGROUND: Assessment of genetic diversity in a crop-breeding programme helps in the identification of diverse parental combinations to create segregating progenies with maximum genetic variability and facilitates introgression of desirable genes from diverse germplasm into the available genetic base. RESULTS: In the present study, 39 strains of vegetable amaranth (Amaranthus tricolor) were evaluated for eight morphological and seven quality traits for two test seasons to study the extent of genetic divergence among the strains. Multivariate analysis showed that the first four principal components contributed 67.55% of the variability. Cluster analysis grouped the strains into six clusters that displayed a wide range of diversity for most of the traits. CONCLUSION: Cluster analysis has proved to be an effective method in grouping strains that may facilitate effective management and utilisation in crop-breeding programmes. The diverse strains falling in different clusters were identified, which can be utilised in different hybridisation programmes to develop high-foliage-yielding varieties rich in nutritional components. Copyright © 2009 Society of Chemical Industry [source]

Simple sequence repeat-based diversity in elite pigeonpea genotypes for developing mapping populations to map resistance to Fusarium wilt and sterility mosaic disease

PLANT BREEDING, Issue 2 2010
R. K. Saxena
With 1 figure and 3 tables Abstract In order to maximize polymorphism in the mapping populations for mapping loci for Fusarium wilt (FW) and sterility mosaic disease (SMD) resistance in pigeonpea, a set of 32 pigeonpea lines were screened for polymorphism with 30 microsatellite or simple sequence repeat markers. A total of 23 marker loci showed polymorphism with 2,4 alleles and the polymorphism information content for these markers ranged from 0.12 to 0.65 with an average of 0.43 per marker. High number of polymorphic markers, higher genetic dissimilarity coefficient and contrasting phenotypic data taken into consideration and five parental combinations were identified and crosses initiated for developing five genetically diverse mapping populations. Of these crosses, one cross segregates for FW resistance, two for SMD resistance and the remaining two crosses segregate for resistance to both FW and SMD. Development of mapping populations is in progress for mapping loci for resistance to FW and SMD in pigeonpea. [source]

Genetic differentiation analysis of African cassava (Manihot esculenta) landraces and elite germplasm using amplified fragment length polymorphism and simple sequence repeat markers

ANNALS OF APPLIED BIOLOGY, Issue 2 2009
A.A.J. Raji
Abstract Molecular-marker-aided evaluation of germplasm plays an important role in defining the genetic diversity of plant genotypes for genetic and population improvement studies. A collection of African cassava landraces and elite cultivars was analysed for genetic diversity using 20 amplified fragment length polymorphic (AFLP) DNA primer combinations and 50 simple sequence repeat (SSR) markers. Within-population diversity estimates obtained with both markers were correlated, showing little variation in their fixation index. The amount of within-population variation was higher for landraces as illustrated by both markers, allowing discrimination among accessions along their geographical origins, with some overlap indicating the pattern of germplasm movement between countries. Elite cultivars were grouped in most cases in agreement with their pedigree and showed a narrow genetic variation. Both SSR and AFLP markers showed some similarity in results for the landraces, although SSR provided better genetic differentiation estimates. Genetic differentiation (Fst) in the landrace population was 0.746 for SSR and 0.656 for AFLP. The molecular variance among cultivars in both populations accounted for up to 83% of the overall variation, while 17% was found within populations. Gene diversity (He) estimated within each population varied with an average value of 0.607 for the landraces and 0.594 for the elite lines. Analyses of SSR data using ordination techniques identified additional cluster groups not detected by AFLP and also captured maximum variation within and between both populations. Our results indicate the importance of SSR and AFLP as efficient markers for the analysis of genetic diversity and population structure in cassava. Genetic differentiation analysis of the evaluated populations provides high prospects for identifying diverse parental combinations for the development of segregating populations for genetic studies and the introgression of desirable genes from diverse sources into the existing genetic base. [source]