Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 146

All genes are expressed in an environment (phenotype = genotype + environmental effect). However, quantitative traits tend to be influenced to a greater degree than qualitative traits. Under significantly large environmental effects, qualitative traits (controlled by one or a few major genes) can exhibit quantitative trait inheritance pattern. A strong environmental influence causes the otherwise distinct classes to overlap (Figure 4.1).

Figure 4.1 Environmental effect on gene expression. The phenotype = genotype + environment. Some traits are influenced a lot more than others by the environment. Cross (a) has small environmental influence such that the phenotypes are distinguishable in the F₂; in cross (b) the environmental influence is strong, resulting in more blurring of the differences among phenotypes in the segregating population.