Response of cowpea genotypes to zinc in relation to photosynthesis,nodulation and dry matter distribution

Summary Photosynthesis, nodulation and dry matter distribution in four cowpea genotypes were examined at three levels of zinc in soil. Genotypic differences were observed in the extent of depression in yield under zinc deficiency and in the level of zinc requirement. The seed yield response to zinc was reflected mainly on the number of pods, because of better realisation of flowers into pods. These results have been discussed in relation to nodulation, dry matter distribution and zinc uptake in these genotypes.