Selection criteria for early maturing cowpea (Vigna unguiculata L. Walp.) genotypes in northern Ghana

English

Growth characteristics on which selection for seed yield could be based in early maturing cowpea were investigated in multilocational trials during the 1997 cropping season using representative samples of 14 cowpea genotypes. Th trial locations were Damongo, Manga, Nyankpala and Wa, representing the diverse agroecologies within northern Ghana. Differences in days to flowering between locations which affected timing and rates of subsequent physiological processes resulted in yield differences between locations. Cause-effect investigations of genotypic yield differences in each location using path analysis have shown that crop growth rate and harvest index are the two most important characteristics on which selection for seed yield could be based, irrespective of location. For the Sudan savanna ecology, the reliance on these two traits has the potential of developing dual-purpose cowpea varieties with high seed and biological yields. The efficiency of crop growth rate and harvest index in explaining the variability in seed yield assessed through regression analyses showed highly significant R, values (P 0.05) for each location.

Padi, F. K.; Marfo, K. O.