SSR markers assay-based establishment of distinctness, uniformity and stability of dolichos bean [Lablab purpureus (L.) Sweet var. Lignosus] advanced breeding lines and elite germplasm accessions

Abstract

Registration of crop varieties under Indian PPV & FR Act requires establishment of their Distinctiveness, Uniformity and Stability (DUS). At present, DUS of crop varieties are being established using morphological traits. DNA marker assay-based DUS testing would complement that based on morphological traits. Four markers, from a total of 220 tested SSR markers were polymorphic among two advanced breeding lines and two elite germplasm accessions (used as candidate varieties), and two released varieties (used as reference varieties) of dolichos bean. The four polymorphic simple sequence repeat (SSR) markers were used to establish distinctness of candidate varieties from reference varieties based on alleles unique to candidate varieties. Uniformity of candidate varieties were established using two criteria, (1) per cent homozygous plants (> 95%) and (2) SSR-homozygous loci ratio (HLR) (> 95%).The candidates which were found uniform at tested SSR loci were deemed stable. The candidate varieties were distinct from reference varieties at two of the four tested polymorphic SSR markers, as evident by the presence of alleles unique to candidate varieties. One hundred per cent homozygous plants and SSR-HLR within all the candidate varieties at all the four tested SSR marker loci suggested uniformity and deemed-stability of candidate varieties. The study demonstrated the utility of SSR markers to establish DUS of ABL/elite germplasm accessions in dolichos bean.