杂种优势在生物界是普遍存在的,利用杂种优势是提高农作物产量和品质的一项有效技术措施。在棉花方面,以印度开展人工杂交制种较早,1977年杂交棉面积已达1200万亩。美国1973年已培育出胞质雄性不育系并实现了三系配套,1977年利用蜜蜂传粉进行大面积生产试验。美国的一些育种家认为,棉花生产今后十年的重大突破,可能就 Heterosis is ubiquitous in the biological world. The use of heterosis is an effective technical measure to improve crop yield and quality. In cotton, artificial hybridization was carried out in India earlier, and the hybrid cotton area in 1977 reached 12 million mu. The United States in 1973 has cultivated a cytoplasmic male sterile line and achieved a three-line package, in 1977 the use of bee pollination for large-scale production test. Some breeders in the United States believe that major breakthroughs in cotton production in the next ten years are possible