Genetic Architecture of Secondary Yield Components in Mungbean (Vigna radiata (L.) Wilczek).

Triple Test Cross (TTC) analyses were carried out to detect epistasis, and to estimate additive and dominance components of genetic variation in two seasons (kharif and spring/summer) for branches per plant, pod clusters per plant, pods per cluster, pod length, biomass, and harvest index in mungbean. The results revealed the absence of epistasis for all the traits in the kharif season but in contrast the presence of epistasis for pod clusters per plant and biomass in the spring/summer season. The partitioning of total epistasis revealed that both i type (additive × additive), and j and l type (additive × dominance, and dominance × dominance) interactions were significant with predominance effect of i type for pod clusters per plant and biomass. The additive and dominance gene effects were highly significant for branches per plant, pod length, and harvest index in both seasons; for pod clusters per plant and biomass in the kharif season; and for pods per cluster in spring/summer season. The magnitude of additive variance was higher for all these traits in both seasons except for pods per cluster and pod length in the spring/summer season, which exhibited a higher value of dominance than additive variance. The direction of dominance was observed towards fewer pod clusters per plant, small pod size, and high harvest index. The predominance of i type interaction and additive gene action for most of the traits in the present investigation suggests the occurrence of selection in the late generations in the segregating population for the improvement of seed yield through yield components in mungbean.