Induced mutations for the improvement of bambara groundnut (Voandzeia subterranea (L.) Thou.), cowpea (Vigna unguiculata (L.) Walp.) and winged bean (Psophocarpus tetragonolobus (L.) D.C.)

A mutation breeding programme to produce mutants with resistance to weevil damage in cowpea, high yield in bambara groundnut and erect growth habit in winged bean was started in 1985. Dry seeds were irradiated using a 60Co source of gamma rays at doses of 350, 250 and 0-350 Gy for cowpea, winged bean, and bambara, respectively. The highest percentage of germination and greatest variability in pods per plant and seed yield per plant occurred at the 150 Gy dose, while vegetative mutants were more frequent at higher doses in bambara groundnut. Several forms of abnormal stem and leaf characteristics occurring within the first to sixth leaf stages of growth were observed in M1 winged bean plants. Seeds with lighter testa colour which showed some resistance to weevil damage were observed in the M1 seed lot of the cowpea variety TVX 1843-1C. Single plant selection for the desirable agronomic traits will be done in the M2 generation for the three crop species. (author). 6 refs, 3 figs, 3 tabs