Preliminary Studies on Cowpea (Vigna unguiculata) Offers Opportunity for Selection in the Guinea and Sudan Savanna Agro Ecologies of Ghana

Genotype by environmental interaction is important for breeding improved cowpea genotypes. The study was designed to identify promising inbred lines with high yield potential, stable mean yield with specific adaptation to a particular environment or environments. The study was conducted at three locations namely Nyankpala, Tumu, and Damongo. Twenty-two inbred lines plus 2 contrasting parents used to generate inbred lines were the test genotypes. Randomized complete block design with 4 replications was used. Seeds were planted at each location but were later thinned to one plant per hill. Each plot contained 5 rows of 10 plants per row with plant spacing of 60 cm between rows and 20 cm within rows with the number of entries being 24 plots giving the total plots as 96 plots for each location. Data collected were days to first flowering, 50% flowering, number of pods per plant, number of seeds per pod and hundred seed weight and grain yield. Data were subjected to analysis of variance using Gen Stat statistical package 12th edition. Combined analysis of variance across locations for grain yield were determine. Results showed significant genotypic differences among inbred lines for studied traits. significant genotype by environment interaction was observed for days to 50% flowering, ranging between 42 and 45 days. Number of pods per plant, number of seeds per pod and biomass also showed variable responses across locations. Phenotypic correlation analysis for days to flowering and maturity did not have any influence on yield, as genotypes 116, 189, 131 flowered within 43 and 45 days with corresponding yields of 1.89,1.82 and 1.7 tonnes per hectare. Yield variability showed the possibility for selecting location specific adapted lines as well as across all three locations.