EPISTASIS IN THE RESISTANCE OF PEPPER TO PHYTOPHTHORA STEM BLIGHT (PHYTOPHTHORA-CAPSICI L) AND ITS SIGNIFICANCE IN THE PREDICTION OF DOUBLE CROSS PERFORMANCES

Epistatic effects are present in the resistance to Phytophthora capsici in peppers (Capsicum annuum). Genetic statistical analysis shows that additive by additive epistasis as well as higher order epistatic effects contribute to the total variation of resistance, significantly. Higher order epistatic effects caused bias in the prediction of the performance of double crosses, the difference between observed and predicted performances being significant. The relative importance of higher order epistasis with respect to additive by additive epistasis seems to be correlated with the aggressiveness of the isolate of Phytophthora capsici.