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利用棉花杂种F_1是棉花育种家多年来的愿望。人们通过大量的研究表明,杂种F_1比其双亲平均值增产18%,这主要是增加了有效铃(增加13.5%)和铃重(增加8.3%),杂种的纤维品质改善较小(0～2%)。雄性不育细胞质的发现给育种家以很大的鼓舞,由于恢复系的可育性太差,因而未能实现商业化杂种F_1的生产。后来有人试验用化学杀雄法生产杂种F_1,然而缺乏经济可靠的控制昆虫传粉的方法,杂种F_1未能在生产中得到应用。为了解决杂种F_1种子不足问题,人们对杂种F_2进行了大量的研究。杂种F_2被认为只有F_150%的杂种优势,当杂种F_2同高产亲本比较时则杂种优势更低。Meredith和
The use of cotton hybrids F_1 is a cotton breeder’s desire for many years. A large number of studies have shown that F_1 hybrids yield 18% more than their parents average, mainly increasing the effective bell (13.5% increase) and boll weight (8.3% increase), and the hybrid fiber quality improvement is small (0-2 %). The discovery of male-sterile cytoplasm has greatly encouraged breeders and failed to achieve the commercial hybrid F_1 production due to the poor fertility of the restorer line. Later, some people tried to use the chemical kill male method hybrid F1, but the lack of economic and reliable method of controlling insect pollination, hybrid F_1 failed to be applied in production. In order to solve the problem of hybrid F_1 seed deficiency, a large number of studies have been conducted on hybrid F_2. Hybrid F_2 is considered to be only F_150% heterosis, and heterosis is lower when F_2 hybrids are compared to high-yielding parents. Meredith and