Development and evaluation of drought resistant mutant germplasm of Vigna unguiculata and Vigna Subterranea

The aim of this project was to select cowpea and bambara groundnut plants with improved levels of drought resistance without alteration to the colour of the testa or the growth form. M2 to M5 generation plants were tested. The M2 to M4 plants were evaluated in the wooden boxes in the greenhouse and the field. Six cowpea mutant lines and seven bambara groundnut lines were included in a physiological screening experiment that was conducted in the greenhouse. One cowpea line exhibited high yield under watered conditions, and three under drought stress conditions. Three bambara groundnut mutants yielded more than the parent, and one showed relatively high yield under drought stress. It proved possible to examine mutant plants at the seedling stage in wooden boxes, mature plants were screened in rain-out shelter and physiological traits were distinguished among the tested lines for drought stress. Roots of mature plants were also assessed and variation could be correlated with drought tolerance. Chlorophyll fluorescence was found to be a good predictor of plant performance in drought conditions. (author)