The inheritance of seed resistance to Callosobruchus maculatus F. in cowpea ( Vigna unguiculata L. Walp.). II. Analyses of percentage emergence and emergence periods of bruchids in F4 seed generation of two reciprocal crosses

Seed from F3 generation plants of two reciprocal crosses were evaluated for bruchid resistance, over 28 F3 families of four plants each plus an additional five plants each in 10-11 families. The variables, percentage adult emergence for a specified period and mean time to emergence, agreed with respect to describing segregation in the resistant, intermediate and susceptible categories. Resistance was expressed as a recessive character. No differences between families from reciprocal crosses were detected. There was evidence for digenic control of resistance in one cross and for monogenic control in the other, in conjunction with one, or more, modifier or minor gene loci. There was general agreement between the results for the F3 generation study and a previous study on the F2 generation.