Strain of Rhizobium effects on growth and seed yield of cowpeas (Vigna unguiculata)

Summary Plant of cowpea (Vigna unguiculata (L.) Walp.) cv. TVu 1469 were grown in a plastic house set to simulate tropical temperatures. They were inoculated with one of two strains of Rhizobium and irrigated each day with nutrient solution either devoid of inorganic nitrogen (N) or containing 2.14 mM (30 ppm) N. Strain of Rhizobium significantly affected rates of dry matter and N accumulation as well as the total N content of mature plants. Variations in seed yield were due largely to Rhizobium effects on peduncle production and pod set on each peduncle, wheres inorganic N did not change these yield-determining components significantly. The agronomic and physiological implications of these data are discussed. One of a series of papers resulting from a collaborative project with the International Institute of Tropical Agriculture, Nigeria; sponsored by the U.K. Overseas Development Administration.