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杂交优势的利用已有悠久的历史,近年来的应用更加广泛.棉花、烟草、高粱、玉米等很多作物都巳开展了这方面的研究工作,而玉米的成效最显著.玉米上利用杂交优势的方法很多,如品种间杂交种、顶交种、单交种、三系杂种、杂交种和综合品种等等,其中以双交种优势最大,因而它是现代玉米育种的主要方向.但是,杂交种的育成需要较长时间,技术也较复杂,短期内难以全面普及.为了迅速提高玉米产量,综合品种的选育应用,在现阶段的玉米生产上,有重要的意义.试验和实践证明,一般优良的品种间杂交种较普通品种增产15—25%,双交种增产30%以上,而优良的综
The utilization of heterosis has a long history and has been applied more widely in recent years.Many crops such as cotton, tobacco, sorghum and corn have carried out research work in this field, while the effect of corn is the most remarkable. There are many methods, such as interbreeding, topcrossing, single crossbreeding, three-line hybrids, hybrids and comprehensive varieties, among which the double cross has the biggest advantage and therefore it is the main direction of modern maize breeding. Breeding of the species takes a long time, the technology is also more complex, it is difficult to popularize in the short term.In order to rapidly increase the yield of maize, the breeding application of the integrated varieties has important significance in the current stage of corn production.Experiments and experiments show that, In general, excellent varieties of hybrids yield 15-25% more than ordinary varieties, double cross species increased yield more than 30%, and excellent comprehensive