Genetic Analysis of the 1000-Grain Weight Trait in Interlinear Hybrids of Winter Rye (Secale cereale L.)

Abstract

The aim of the study is to quantify the contribution of additive, dominant, and epistatic dispersions to the overall genetic variation of the 1000-grain weight trait to increase the efficiency of breeding heterotic hybrids of winter rye. The experiments were carried out at the experimental base of the Federal Research Center Nemchinovka (Moscow oblast). The starting material was ten male sterile homozygous inbred lines carrying the Pump-type cytoplasm. These lines were crossed with two male fertile test lines: mf H-842 and mf H-1247. Test crosses were carried out in 2019 on two isolated plots according to the topcross scheme. The resulting hybrids and their parent forms were tested in 2020 and 2021 on plots of 8 m² in twofold repetition. The test for epistasis and decomposition of the genetic varianсе into additive and dominant components was carried out by the method of Jinks, Perkins, and Brees (1969). The data show that the additive interaction of genes, as well as incomplete dominance, plays the main role in determining the trait of granularity. A stable ratio of these interactions was established over the years: the proportion of additive effects varied at the level of 83.9–84.7%, and the proportion of dominant effects at the level of 15.3–16.1%. The indicator of the degree of dominance  $\sqrt {{\text{(}}H1{\text{/}}D{\text{)}}}$ was less than one and varied slightly over the years. It follows from this that dominant alleles affecting gross grain do not completely suppress the effect of their recessive alleles. For this reason, simple interlinear hybrids inherit an intermediate phenotype compared to the parent forms. The most coarse-grained hybrids were obtained by crossing lines ms H-1054, ms H-649, and ms H-1090 with the coarse-grained tester mf H-1247. It is concluded that, in the synthesis of commercial rye hybrids, it is necessary to strive to ensure that all parent forms are gross-grained. To obtain such lines, it is advisable to use methods of recurrent selection as well as convergent and cumulative breeding.