The inheritance of plant height in crosses involving short-stem rye genotypes

The paper presents results of studies on the inheritance of plant height in four short-stem genotypes of rye selected from genotypically different collection materials. Short-stem genotypes P-2, P-9, P-30 and P-52 were crossed to a tall-stem inbred line Uniwersalne 145 (S₁₇). The genotype P-2 was additionally crossed to a related, but tall-stem line P-2 W. In each cross combinations six generations - P₁, P₂, F₁, F₂, B₁ (F₁ × P₁) and B₂ (F₁ × P₂) - were examined. Distribution of plant height in hybrid generations had a continuous character, which indicated a polygenic determination of short stem in all "P" genotypes under study. Results of the genetic analysis (degrees of dominance, Burton method, Mather and Cavalli scaling tests, a six-parameter model of inheritance) showed a significant role of additive, dominant and epistatic gene action in genetic determination of short stem in the "P" genotypes. Only in the cross Uniwersalne 145 × P-52 one of the applied methods (a six-parameter model) has not confirmed a significant role of epistasis and dominance. In the cross combinations Uniwersalne 145 × P-2, Uniwersalne 145 × P-9 and Uniwersalne 145 × P-30 a reduction of the plant height was influenced by homozygote × homozygote and homozygote × heterozygote interactions as well as by dominance effects, whereas the plant height increase was influenced by heterozygote × heterozygote interaction as well as by effects of additive gene action. The combination P-2W × P-2 was found to have reverse relationships. The revealed epistasis had a duplicate character. The heritability of plant height was relatively high and varied from 70.4% to 84.9% depending on the cross combination.