Inheritance of resistance to Fusarium root rot (Fusarium redolens) in selected genotypes of cowpea in Uganda

Cowpea production in Uganda is constrained by Fusarium root rot disease caused by Fusarium redolens. The use of resistant cultivars is the most economical long-term strategy to manage the disease and knowledge of the inheritance of resistance to the disease is important for cultivar development. Ten parents were crossed using a North Carolina mating Design II. Four of the parents were used as males and the other six of them as female parents. Of the female parents, four had intermediate resistance while two were susceptible. The resistant male parents were Asontem, Danila, IT89KD-288 and NE 70. The four female parents with intermediate resistance were SECOW 2W, SECOW 3B, NE 50 and NE 6 while the susceptible female parents were KVU 27-1 and WC 66. The F2 progeny alongside the parents were planted in wooden boxes containing soil inoculated with F. redolens in the greenhouse. Severity of Fusarium root rot was scored using the CIAT 1 to 9 scale at 28 days after planting. Data were subjected to Analysis of Variance. General combining ability (GCA) was significant (P0.05) indicating that non additive genetic effects were not important. The chi square test suggested the action of single gene with dominance for some parents used in the crosses and at least two gene pairs with epistasis for other parents.