Analysis of chlorophyll pigmentation for yield prediction in cowpea varieties (Vigna unguiculata (L) Walp)

Abstract

Six cowpea genotypes; UCC-W, UCC-E, UCC-P1, UCC-P4, UCC-07 and UCC-V6 were evaluated in the research field (Technology village) of School of Agriculture, University of Cape Coast, Ghana during the 2006/2007 cropping season. The experimental layout was Randomize Complete Block Design with two replications. Each cowpea genotype leaflets were sampled at 5, 6, 7th weeks after planting for molar absorbtivity and optical density coefficients as indicators for yield prediction at seedling stage. Leaf chlorophyll content was extracted using spectrophotometer set at a wavelength of 634nm. The samples were irradiated using radio isotope directed towards the sample. There was significant genetic variability among the cowpea genotypes. High chlorophyll absorption and optical film density were obtained for UCC-W, UCC-07 and UCC-E with a corresponding high yield and yield components. Between 5th and 6th week after planting was efficient for yield prediction in the cowpea genotypes. Chlorophyll absorption and optical film density are positively and highly related, with high coefficient of determination for all the cowpea genotypes. Thus, either spectrophotometer or beta radiography or both could be used as yield prediction tool in screening and selection of cowpea genotypes