Response of cowpea genotypes [Vigna unguiculata (L.) Walp.] to artificial pollination in the tropics
Keywords:Hybridization, Genotype x environment, Crossing methods, Pollination
AbstractThree experiments were conducted to understand the factors that determine podset in cowpea [Vigna unguiculata (L.) Walp.)] with artificial pollination 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 two methods of pollination (conventional and rapid). The percentage podset success obtained varied from 10 to 65, depending on the female parent and the crossing method. The conventional method was superior to the rapid method in female parents that gave a low success percentage, but was similar to the rapid method in female parents that gave higher podsets. Differences among female parents seemed to be related to floral 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 evident. The differences between the rapid method and the conventional method were not evident in the third experiment, when genotypes were grown under 'optimized' conditions as determined in the second experiment. The study indicates that podsets as high as 90% can be obtained provided the pollination conditions are standardized to suit the female parent involved and by appropriate choice of female parent.