Molecular characterization and development of mapping populations for construction of genetic map in Dolichos bean [Lablab purpureus L. (Sweet)]

Abstract

Fieldbean {Lablab purpureus L. (Sweet)} is an important pulse crop in India. Though newlineit is being one of the ancient crops with rich genetic diversity and adaptability to varied edaphic factors, it has not attained the level of agricultural significance as expected. To facilitate the breeding activities the present study was conducted in relation to marker and population development with the aim of providing tools for the study of Indian fieldbean. The morphological characterization, development of F2 mapping populations, Molecular diversity of selected fieldbean using COS legume markers and molecular characterization of 224 germplasm accessions were carried out at GKVK, UAS, Bengaluru. The screening of selected fieldbean accessions to identify polymorphic markers and their validation in F2 newlinemapping populations were carried out in John Innes Centre, Norwich, UK. The diversity newlineanalysis showed that Fieldbean genotypes of Indian origin grouped into one single cluster newlinewhile genotypes from African origin grouped into second cluster. Principal component newlineanalysis for 71 traits in 224 germplasms revealed 81% of variation in the population by first four principal components. High rate of amplification of cowpea genic SSR primers in fieldbean showed high marker transferability between these two legumes. Four polymorphic markers were identified newlinein parental genotypes when separated on 5% horizontal polyacrylamide gel while these were monomorphic on 2% agarose gel. The sequencing of 18 genic fragments among nine parental genotypes, revealed 60 SNPs and 16 InDels. Using SNPs and InDels information of genic fragments allele specific markers were developed. Four molecular marker systems viz., sequencing of genic fragments, SNPs, allele specific PCR markers and InDel markers were used successfully to genotype the F2 populations of HA4×CPI31113 and HA4×CPI60216 newlinecrosses and they exhibited 1:2:1 ratio.