Mechanisms sustaining displacements of quantitative trait dominance in spring wheat of various geographical regions

The mechanisms of displacements of quantitative trait dominance in spring wheat are discussed in terms of the theory of the ecological genetic organization of quantitative traits. A conventional interpretation of displacements of genotype points on Hayman’s graphs in terms of classical diallelic crosses does not require that limiting environmental factors be monitored during the ontogenetic development of quantitative traits or that changes in the set of trait-determining genes upon a change of the limiting factor be considered. Analysis of the experimental data of the DIAS program in terms of the new theory of the ecological genetic organization of quantitative traits revealed two mechanisms that determine displacements of genotype points along the regression line on Hayman’s graphs. One is a metric scale effect, which arises as a result of a correlation of mean values and variances of a trait in rows of the parents and F 1 hybrids in the diallelic matrix. The other is an environment-depending change arising in the set and number of genes that underlie a multicomponent trait and determine their final value in a multiplicative manner.