SEED AND POD RESISTANCE TO CALLOSOBRUCHUS-MACULATUS AMONG VARIOUS VIGNA SPECIES

Accessions of Vigna vexillata, Vigna oblongifolia, and Vigna unguicula ta (subspecies unguiculata, dekindtiana, and pubescens) were evaluated under laboratory conditions to identify sources of seed and/or pod re sistance to the cowpea weevil Callosobruchus maculatus. TVnu 37 and TV nu 88 (V. oblongifolia) and TVnu 72 (V. vexillata) possessed high leve ls of seed resistance. On mature, dry pods, seventeen-fold differences in mean eggs laid/cm2 were observed, suggesting that ovipositional no npreference could be a practical form of resistance to C. maculatus. I n infested pods, pre-establishment larval mortality (mortality before larvae become established in seeds) varied among accessions, ranging f rom 19.3% in N1 778 (cv-gr. Biflora) to 91.3% in NI 816 (cv-gr. Textil is). The total percentage larval mortality in infested pods ranged fro m 34.6 % in TN 88-63 (V. unguiculata) to 100% in TVnu 72 (V. vexillata ) and NI 816 (cv-gr. Textilis) with the majority of accessions produci ng over 80% mortality. Higher levels and more durable forms of bruchid resistance might be achieved by combining seed and pod resistance.