Relationships between hard-seededness and seed weight in mungbean (Vigna radiata) assessed by QTL analysis

Weather damage reduces the value of commercial mungbean. but hard-seededness can reduce the level of damage. However. attempts lo breed large- and hard-seeded mungbean varieties have been unsuccessful. To understand the relationship between seed weight and hard-seededness. these trails were investigated using a quantitative trail loci (QTL) mapping approach with a recombinant inbred population derived from a cross between a completely soft-seeded variety and a completely hard-seeded genotype. The two parental genotypes also had a sixfold difference in seed weight. QTL analyses revealed four loci for hard-seededness and 11 loci for seed weight. Two of the hard-seeded ness loci co-localized with seed weight QTL. When seed weight was used as a covariate in the analysis of hard-seededness from the field data, two of the four hard-seeded QTL remained significant with the effect al one of these remaining unchanged. These results explain why retaining hard-seededness in large seeded mungbean lines has been unsuccessful. The existence of a persistent locus, however. indicated that breeding large and persistently hard-seeded varieties of mungbean may be possible.