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Development of synthetic tetraploids (New source of tetraploid groundnut)

Title : Development of synthetic tetraploids (New source of tetraploid groundnut) Speaker: Ms P Krishnashilpa Ph.D. Scholar RP-Grain Legumes ICRISAT Time : 1000 -- 1100 h Venue : 212 CF Bentley Conference Center Abstract : Peanut, an amphidiploid/tetraploid, is cultivated in many parts of the world and is susceptible to a range of diseases and pests, owing to its narrow genetic base. Whereas, it's wild relatives are genetically diverse and resistant to majority of the biotic and abiotic constraints. Unfortunately wild Arachis species are difficult to use to introgress useful disease and pest resistance traits due to ploidy difference between the two groups. Peanut has an interesting evolutionary history wherein two diploid Arachis species with A and B genomes have contributed to form tetraploid. Imitating this evolutionary feature, major initiative was taken at ICRISAT to create new sources of tetraploid (synthetic) peanut by combining original A, B and K genome species. This has resulted in the creation of a range of tetraploids (synthetics). Most recently, crosses were made between the two such tetraploids to create double synthetics with the intension of creating highly variable tetraploids as only two synthetics were available for peanut improvement. Care was taken to see that double synthetics comprised of a minimum of three Arachis species and a maximum of four. Meiotic analysis and molecular analysis was done for these double synthetics. The meiotic analysis of double synthetics showed good homology between two parental synthetics and high recombination between parental genomes, which ultimately resulted in high pollen fertility. Molecular characterizations by SSR marker analysis of the genotypes gave precise information about the extent of genetic diversity.