Inheritance of nodulation and N sub(2) fixation in winged beans

The inheritance of nodulation and N sub(2) fixation in winged beans, Psophocarpus tetragonolobus) (L.) D.C., was studied through heritability estimates and generation mean analysis. Broad sense heritability and narrow sense heritability and heterosis of these characteris were determined by variance assessment of parental, F sub(1), F sub(2), and backcross populations after crossing two true breeding homogenous land varieties - TPT sub(1) and UPS sub(122). Nodulation in winged beans showed low heritability (24.94 percent). But considerable genetic advance could be obtained since the additive effect was larger than that of dominance. Selection for nodulation should be undertaken in late generations such as F sub(5) to F sub(7). The heritability for N sub(2) fixation was relatively high (58 percent) and substrantial genetic advance could be attained in generations as early as F sub(2).