Effects of Sowing Dates on the Growth and Yield of Cowpea Varieties in Minna, Southern Guinea Savanna of Nigeria

Abstract

With climate change being experienced in recent times, there is the need to determine the most appropriate time to plant cowpea in the Guinea savanna agro-ecological zone of Nigeria which account for the major production of the crop in the country. A field trial was therefore conducted to determine the effect of sowing dates on the growth, biomass and grain yield of cowpea in Minna, the Southern Guinea savanna agroecological zone of Nigeria. The treatments consisted of nine sowing dates (planting at 2 weekly intervals from 19th May to 8th September, 2017) and three cowpea varieties (IT93K-452-1, Oloyin and Kanannado). Results obtained revealed that plants sown between 19th May and 28th July had significantly larger leaf area than those sown later. Plants sown on 2nd June had the highest number of branches which was at par with the value recorded in those sown on 19th May and 16th July. Plants sown on 28th July had the highest number of leaves while plants sown between 19th May and 2nd June had the longest vines. The widest stems were observed in plants sown on 19th May and they were significantly (P≤0.05) wider than the stem of plants sown after 14th of July. The least values for all the growth attributes were recorded in plants sown on 8th September. Kannanado and Oloyin plants sown on 19th May produced the highest biomass yield while IT93K-452-1 variety produced the highest biomass yield when sown on 2nd June. Kanannado variety had the highest grain yield when sown on 28th July. Oloyin and IT93K-452-1 varieties had their highest grain yield when sown on 19th May and 1st July. Significantly lower grain yield was obtained in the three varieties when sown after 11th August. Among the varieties, Kanannado had the highest biomass yield but the least grain yield while IT93K-452-1 had the highest grain yield.