N. M. Akpan, I. I. Dominic Gene action, pepper, diallel, heritability, yield 110-117 8(4) 2024 October, 2024 Gene action of yield and yield contributing traits of peppers (Capsicum spp) was studied in half diallel mating design involving seven (7) parental genotypes to generate twenty one (21) single cross hybrids during 2022 (April-July) planting season at the Department of Crop Science teaching and research farm University of Uyo, Uyo. Parents and the F1’s were planted during August-December, 2022 to produce F_2’s and some F₁ plants were back cross to their respective parents to produce their backcrosses (BCP1 and BCP2). The F₂ and backcrosses were evaluated during April-July, 2023 planting season. The data obtained were subjected to generational mean analysis to determine the type of genes action involves in yield and yield contributing traits of pepper. Heritability in broad and narrow sense were estimated. The result showed that, all types of gene action i.e. additive, dominance and interaction components were found to play a major role in the inheritance of yield and yield contributing traits of pepper. High broad sense heritability (>70%) and narrow sense heritability (>50%) for fruit yield per hectare was obtained in all the hybrids with few exceptions. Dominance gene effect was found to be positive and higher in magnitude in all the hybrids for number of fruits per plant, fruit weight per plant and fruit yield per hectare when compared with other genes action indicating hybridization (heterosis breeding) as the best breeding method to improve the productivity of pepper.