玉米双交种的优越性已为世所公认,于同等技术与自然条件下,一般可增产25～75％,成为国外和国内发展玉米生产的共同方向。但由于双交种二代以后分离严重、杂种优势锐减,需建立较完整的繁殖体系,每年配制大量的单、双交种。因此,稳定玉米双交种杂种优势的问题,具有重大的现实生产意义和理论价值。黑龙江省农业科学院1958年利用X射线照射农家品种“牛尾黄”种子,在后代中发现有大 The superiority of corn double crosses has been universally acknowledged. Under the same technical and natural conditions, the yield can generally increase by 25% to 75%, becoming the common direction for the development of corn production both domestically and domestically. However, due to the serious segregation after the second generation of double crossbreds and the sharp reduction of heterosis, it is necessary to establish a more complete breeding system and prepare a large number of single and double crossbreds each year. Therefore, the problem of stabilizing the heterosis of maize hybrids has great practical significance and theoretical value. Heilongjiang Academy of Agricultural Sciences in 1958 using X-ray irradiation farm variety “Oxtail yellow” seeds, found in the offspring of large