Genetic effects of important yield traits analysed by mixture model of major gene plus polygene in wheat

Abstract

The important traits represented by yield per plant are the main target traits in high-yield breeding of wheat, and analysing then the quantitative genetic characteristics will provide a basis for further study on the genetic mechanism. In this study, we selected the winter Pingdong 34 as the female parent (P1) and the Barran as the male parent (P2) to configure the hybrid combination, and applied the main gene + polygene mixed genetic model method to analyse the length and number of tillers in the single generation (P1, P2) RIL7:8, RIL8:9 at four environments in two years genetic model and correlation among yield per plant, 1000-grain weight, plant height, internode length, internode length and number of tillers. There were significant or extremely significant condation among all the traits, except for the 1000-grain weight and number of tillers. The average correlation coefficient between the internodes and the upper leaves of the flag was 0.91 ( P ≤ 0.001). The optimal genetic model for yield per plant was four pairs of additive epigenetic gene + polygenic genetic model with the main gene additive effect values of 3.78, 2.89, –6.18, and 0.15, respectively, and the multigene heritability of 86.23%. The optimal genetic model of 1000-grain weight of a mixed genetic model with two pairs of complementary main genes + additive effects. The multi-gene additive effect value was 22.37, the main gene heritability was 66.96%, and the multi-gene heritability was 28.25%. The optimal genetic model of plant height was a mixed genetic model of two pairs of cumulative main genes + additive multigenes. The additive value of the first pair of main genes controlling plant height was 5.15. Additive × additive epistatic interaction value was –9.66, the multigene additive effect value was –9.31, the major gene heritability was 58.57%, and the polygene heritability was 39.71%. The optimal genetic model of the internode length below spike above the flag leaf was the additive-superordinate multi-gene genetic model, and the main gene heritability was 97.65% and 99.14%, respectively. The optimal genetic model of the number of tillers was an additive-superordinate multi-gene mixed genetic model with a genetic rate of 78.89% for primary genes and 19.87% for multiple genes. These traits were mainly dominated by the combination of major gene + polygene in multiple environments. In the process of breeding excellent strains, it is necessary to take into account the important performances adapting to the ecological environment conditions, and further provide a theoretical basis for screening closely linked to target traits markers and promoting molecular marker-assisted selection.