Abstract: Fifteen capsicum combinations were made with 6 parents by (1/2) n (n-1) diallel crossing. Genetic parameters in the resistance to TMV, CMV, phytophthora blight, bacterial spot of these combinations were studied by Hayman. The results indicated that the resistances to TMV, CMV and bacterial spot conformed genetically to the "additive-dominant" model but the resistance to phytophthora blight did not and significant epistatic dominance effect existed in it. F1 hybrid's resistance to CMV was controlled by homozygous dominant gene(s), but resistance to bacterial spot by heterozygous one(s). There were little, or no sum of dominant effect and genomes controlling the dominant expression of F1 hybrids in its phytophthora blight resistance.

Key words: Pepper (Capsicam annuum L.), Diallel crossing, Resistance to disease, Genetic parameter estimate