Multi-locational evaluation of cowpea grain yield and other reproductive characters in the forest and southern guinea savanna agro-ecologies of Nigeria
Electronic Journal of Environmental, Agricultural and Food Chemistry
Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, P.M.B.5029, Ibadan, Nigeria
Ten cowpea varieties were evaluated for grain yield and other reproductive characters at three locations within the forest and southern guinea savanna agro-ecologies of Nigeria for two years. Significant effects of year, location, variety and year x location interactions were observed for most of the parameters evaluated. Among the varieties average number of days to 50% flowering ranged from 41.89 to 50.06 days. Pod length had a mean value of 14.90cm and that of number of seeds per pod was 12.35. One hundred seed weight varied from 14.52g to 16.44g. Grain yield also ranged from 915. 14 to 1173.40 kg/ha with IT97D-941-1 having the best yield. Significantly higher grain yield was recorded in 2006 with a mean value of 1137.17kg/ha than 2007 (980.11 kg/ha). Among the locations average grain yield at Ballah (southern guinea savanna), Ikenne (forest) and Ilora (derived savanna) were 1016.56 kg/ha, 884.96 kg/ha and 1274.41 kg/ha respectively. GGE biplot analysis showed that genotype x location interaction was responsible for greater proportion of variation (57.61%). The analysis was also used to identify suitable cowpea varieties for each of the three locations under consideration.