Analysis of the Genetic Mechanism of Yield-Related Traits of Maize in Cold Regions.

Maize is an important food crop in cold regions, especially in Northeast China. However, its short growth period and low-temperature stress pose challenges to the breeding of high-yield hybrids. With climate warming, the maize planting area continues to expand to high latitudes. Research on cold-region maize is of great significance to ensure food security and sustainable agricultural development. However, most of the current maize research is concentrated in temperate and tropical regions, and there are few studies on cold-region maize. Based on this, this study selected some representative cold-region maize materials and materials whose adaptability has not yet been verified, and used a semi-diallel hybrid design for hybridization to determine the general combining ability (GCA) and specific combining ability (SCA) to screen out excellent breeding materials suitable for cold regions. Field experiments were carried out under four different cold environments, and 55 hybrid progenies and their parents were evaluated. The double allele hybridization analysis based on the Griffing method 2 (model 1) showed that the specific combining ability (SCA) and general combining ability (GCA) effects of each trait were significant. The GCA mean square of all traits except yield and number of grains per row was greater than the SCA mean square, indicating that additive gene effects were dominant and genetic improvement through selective breeding was feasible. Hayman plot analysis under four environments showed that yield, ear length, number of grains per row, water content, and plant height were mainly controlled by superdominant genes, while stem thickness, number of nodes, and ear position were controlled by some dominant genes. Parent P1 contained more recessive genes in yield traits, but more dominant genes in number of grains per row, number of nodes, and ear position; P3 contained more dominant genes in yield and water content, but more recessive genes in number of nodes and ear position; P7 contained more recessive genes in most traits; and P9 contained more dominant genes in most traits. P9 and P6 represent excellent parental germplasm, among which the hybrid combinations P1 × P9, P2 × P5, P3 × P10, P4 × P6, P5 × P8, P6 × P9, P7 × P10, and P8 × P10 all show hybrid vigor exceeding that of their parents and have high breeding value.