Components of means: interaction and heterosis

Abstract

If we consider two different genes each with two alleles A—a and B—b, nine genotypes are possible in a diploid organism and eight parameters must be used to give a complete description of the differences among phenotypes. Four of these are the ds and hs appropriate to the two genes, i.e. d _a, d _b, h _a and h _b. The other four may then be derived conveniently to correspond to the interaction comparisons between non-allelic genes. The distribution of these four parameters among the nine genotypes using the Robson definitions of the interactions described by Van der Veen (1959) are shown in Table 19.