Validation of molecular markers linked to bruchid resistance in green gram (Vigna radiata)

Abstract

The pulse beetle, Callosobruchus spp., poses a threat to legumes by consuming the protein content of the grain, resulting in potential losses in storage ranging from 12 to 30%. Molecular marker technology helps to mitigate the breeding constraint in the development of bruchid resistance in green gram breeding programmes. In the present study, validation of locus-specific STSbr1 and STSbr2 markers linked with bruchid resistance was done using fifteen genotypes viz., VBN (Gg) 2 (susceptible) and Vigna radiata var. sublobata/2 (resistant), F₁ hybrid, two susceptible and ten resistant RILs derived from the above parents. The marker STS br1 behaved as a dominant marker and produced an approximate allele size of 225 bp in the resistant parent, F₁ hybrid and resistant RILs and absent in susceptible parent and susceptible RILs, which showed cent per cent co-segregation with bruchid resistance locus. Hence, it is concluded that STS br1 is linked with bruchid-resistant genes. The marker STS br2 behaved as a co-dominant marker and produced an approximate allele size of 470 bp in all the 15 genotypes evaluated (monomorphic) and did not differentiate the resistant and susceptible genotypes. The marker STS br1 could be used in marker-assisted selection to develop bruchid-resistant varieties and to screen the germplasm to identify bruchid-resistant donors in green gram.