Abstract:

In field production, new maize varieties with U.S. germplasm such as ‘Xianyu 335’ are weak in resistance to dense planting, lodging, Southern Corn Rust, leaf blight, and high temperature and heat. To solve these problems by means of plant breeding, we use maize new variety ‘Yufeng 303’ as the test material to study its performances, including yield performance, drought tolerance, high temperature and heat tolerance, dense planting resistance, and grain quality at production trials, at national trials (Huang-huai-hai Summer Maize Area, Eastern of North China Middle and Late Maturity Spring Maize Area, and Northwest Spring Maize Area) and provincial trials. The results show that ‘Yufeng 303’ not only possesses the desirable traits of new maize varieties with U. S. germplasm, but also has traits of high tolerances to drought, high temperature and heat, lodging, and Southern Corn Rust, achieving and substantially surpassing our original breeding goal. Based on these results, several issues for future breeding, including the general technical route of germplasm expansion, improvement and innovation, the avoidance of genetic vulnerability risk and others related to commercial breeding, are discussed. The study emphasizes the importance of breeding the traits of high temperature tolerance and drought tolerance, especially the importance of breeding new varieties with wide stress adaptability by constantly uplifting the positive super normal expression of genotype environment interaction.

Key words: maize, Yufeng 303, commercial breeding, variety breeding, high temperature and heat tolerance breeding, drought tolerance breeding