Agromorphological evaluation of six varieties of Cowpea [Vigna unguiculata (L.) Walp.] in the Zinder region (Niger)

Abstract

Cowpea is the main food leguminous plant grown in Niger. It is mainly cultivated for its protein-rich haulms and seeds and for its ability to improve soil fertility through its symbiosis with atmospheric nitrogen-fixing bacteria. The present study evaluated genetic variability among six cowpea varieties for yield, yield related and phenology traits in the Zinder region. The experiment was conducted at the experimental area of André Salifou University in Zinder. An experimental device composed of three completely random blocks was used. The six varieties (four local and two improved) of cowpea were evaluated based on 24 quantitative agronomic and morphological characters according to IBPGR descriptors. The comparison of the means and the PCA revealed significant differences between the varieties in almost all the traits tested, with substantial phenotypic variations. IT98 was the most productive variety, with an average yield of 385.50 kg/ha. It also recorded the earliest flowering (38.41 days after sowing) and maturity (55 days after sowing) dates. BlAr gave the highest 100-Seed weight with an average value of 29.21g. CDSb and BTAr were the tallest plants at 40.44 and 40.26 cm respectively. The completed PCA indicates that the first two axes expressed 78,7% of the total variability whereby PC1 and PC2 highly contributed to the total variation at 54.76% and 23.94, respectively. Thus, IT98 may be a good candidate to be considered in Niger struggle to fight food shortage and face nutrition challenges, especially for the Zinder region due to abiotic constraints.