RESPONSE OF COWPEA GENOTYPES [VIGNA-UNGUICULATA (L.) WALP.] TO ARTIFICIAL POLLINATION IN THE TROPICS

Three experiments were conducted to understand the factors that determ ine podset in cowpea [Vigna unguiculata (L.) Walp.)] with artificial p ollination in the tropics. Eight genotypes (Bush Sitao, TVu 1948, UCR 193, CNCx-102, Laura-B, UCR 1-12-3, Local Red, and IT-83S-911), grown in open conditions, were crossed in all possible combinations using tw o methods of pollination (conventional and rapid). The percentage pods et success obtained varied from 10 to 65, depending on the female pare nt and the crossing method. The conventional method was superior to th e rapid method in female parents that gave a low success percentage, b ut was similar to the rapid method in female parents that gave higher podsets. Differences among female parents seemed to be related to flor al morphology. In a subsequent study, evening pollination that ensured a cooler post-pollination environment was shown to improve podsets in all the genotypes tested, but genotypic differences were still eviden t. The differences between the rapid method and the conventional metho d were not evident in the third experiment, when genotypes were grown under 'optimized' conditions as determined in the second experiment. T he study indicates that podsets as high as 90% can be obtained provide d the pollination conditions are standardized to suit the female paren t involved and by appropriate choice of female parent.