Abstract:

The aim of this study is to investigate the genetic mechanism of cob traits by using genetic model prediction, point out breeding directions for breeders and improve breeding efficiency. The F₂ population containing 390 lines crossed by two parents, FBHJ and MBUB, was used as material. The F₂ single generation analysis method in the quantitative segregation analysis package for plants was used to perform quantitative genetic analysis, correlation analysis and regression analysis of seven cob-related traits, including ear cob length, kernel length, ear cob diameter, kernel width, ear cob weight, 100-kernel weight and kernel thickness. The results showed that the most suitable genetic model for three traits, namely, ear cob diameter, kernel length and kernel width, was A-0, which inherited by no major gene. Ear cob weight and kernel thickness were controlled by two pairs of major genes, and the major genes were additive-dominant-superior, which was consistent with the B-1 model. Ear cob length and 100-kernel weight were controlled by one pair of major genes, and the most suitable models were A-1 and A-3, respectively. The heritability of major genes ranged from 28.37% to 59.11% for each model, with the largest heritability for 100-kernel weight trait. All traits were positively correlated with 100-kernel weight. The regression equation of 100-kernel weight (Y) on other agronomic traits was Y= -57.126+0.176X₁+3.069X₂+2.890X₃+5.108X₄ with a fit degree of 0.723. The indirect effect of kernel width and the direct effect of kernel length were the highest in the throughput analysis. The findings of this study provide a theoretical basis for the genetic resolution of cob traits in maize.

Key words: maize, genetic analysis, agronomic traits, main gene + poly gene, F₂ population