VICILIN VARIANTS AND THE RESISTANCE OF COWPEA (VIGNA-UNGUICULATA) SEEDS TO THE COWPEA WEEVIL (CALLOSOBRUCHUS-MACULATUS)

1. A globulin fraction prepared from the meal of Callosohruchus maculatus-resistant cowpea (Vigna unguiculata) seeds was shown to be detrimental to this bruchid when incorporated in artificial seeds. 2. The performance of C. maculatus was also shown to be strongly hindered by vicilins from resistant seeds when these storage proteins were incorporated in artificial seeds at the level of 2%. 3. The purified vicilins from seeds of both resistant and susceptible cowpea varieties were shown to have the same SDS-PAGE pattern but different mobilities in non-denaturing polyacrylamide gel electrophoresis. 4. These results and previous ones obtained by us (Silva and Xavier-Filho, 1991; Sales et al., 1992) strongly suggest that the resistance of cowpea seeds from the cultivar TVu 2027 and from others bred from it is associated with the presence of vicilin molecules which are refractory to digestion by bruchid midgut proteinases.