Are indeterminate genotypes more productive than determinate ones in dolichos bean [Lablab purpureus (L.) sweet]?: An analysis based on near isogenic lines differing in growth habit

Determinate growth habit is farmer-preferred trait in dolichos bean. Fresh pods are harvestable and marketable economic products in dolichos bean. For ready acceptance of determinate cultivars, they should be in high fresh pod yielding background. Empirical evidence based on non-isogenic backgrounds indicated that genotypes with indeterminate growth habit produce greater fresh pod yield than those with determinate growth habit. However, confounding effects of the genes other than those controlling growth habit on fresh pod yield cannot be ruled out. Near isogenic lines (NILs) are ideal genetic resources to assess un-confounding effect of growth habit on fresh pod yield.

Six pairs of NILs differing for growth habit developed from heterogeneous inbred families (HIFs) of F2:5 recombinant inbred population were field-evaluated in two-replicated RCBD design at three locations for days to 50% flowering, number of fresh pods plant^-1 and fresh pod yield plant^-1. Significance/other-wise of differences between determinate and indeterminate components of NILs were examined using two-sample ‘t’ test with unequal variance.

Indeterminate NILs were late to flower by one week and produced two-fold greater number of fresh pods and higher fresh pod yield compared to their determinate counterpart NILs. Given that NILs used in the present study differed only for loci controlling growth habit, we strongly believe that genes controlling growth habit perhaps have pleiotropic effects on number of fresh pods and fresh pod yield in dolichos bean. These results are discussed in relation to strategies to maximize fresh pod yield potential of determinate cultivars in dolichos bean.