Yield Performance of Cowpea Genotypes Grown in Alkaline Soils, Poster Board #413

Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22% to 25% protein. The crop is very sensitive to alkaline soil conditions.  When grown at soil pH of 7.5 or higher, cowpea develops severe leaf chlorosis caused by deficiencies of Fe, Zn and Mn resulting in stunted plant growth and yield reduction.  We evaluated in replicated field experiments at St. Croix, U.S. Virgin Islands, and Miami, Florida, four plant introductions (PIs) and one commercial cultivar some of which have shown some tolerance to alkaline soils in unreplicated, seed regeneration plots of the U.S. cowpea collection.  Alkaline soil conditions at St. Croix were severe resulting in average yield of genotypes at this location being significantly lower and 69% less than that in Florida.  Nevertheless, some genotypes performed well at both locations.  For example, PI’s 582605 and 582674 had significantly higher yield at both locations as compared to other genotypes used in the study.  These genotypes may serve as an alternative to growers in areas where agricultural production is restricted by high soil alkalinity.