Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 164

Additive genetic variance is known to decrease proportionally to the improvement following selection. In pure line selection, genetic variance is completely depleted with time, until further improvement is impossible. However, mutational events as well as genetic recombination can replenish some of the lost additive genetic variance. On the contrary, additive genetic variance cannot be depleted in intermating populations because auto conversion (self conversion) of non‐additive genetic variance to additive genetic variance occurs. This conversion occurs because heterozygotes become fixed into homozygotes.