In diallel crossing, excluding reciprocal ones, five divergent genotypes of barley (Vada, erdap, NS-293, Jagodinac and Sladoran) were included with the mode of inheritance and gene effect studied using the regression analysis of variance and co-variance for the number of kernels per spike. The absence of inter-allele interaction established using the regression analysis VrWr and WrW resulted from the use of the mode selected. In the inheritance of the number of kernels per spike, the regression pointed at dominant gene effect as well as at the unevenly distributed dominant and recessive genes in the genotypes selected. While Jagodinac, Vada and NS-293 had the highest number of dominant, erdap and Sladoran had the highest one of the recessive genes for the number of kernels per spike. Therefore, in the two-rowed genotypes, the higher number of dominant genes was, the higher number of kernels per spike was, and conversely, the higher number of the recessive genes was, the lower number of kernels per spike was.