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.