INTRODUCTION
Cowpea is a grain legume of the Fabaceae family and native to Asia. The species is widely cultivated
in tropical and sub-tropical regions, particularly in sub-Saharan Africa which accounts for almost all of
world production. It is a self-pollinating, herbaceous, annual plant with a creeping or erect habit. The species offers
enormous nutritional possibilities by providing plant protein to ensure better
nutrition for the population and in the field of soil fertility through its ability to fix atmospheric nitrogen. In Benin, it occupies first place among grain legumes.