三元杂种 [陆地棉× (亚洲棉×比克氏棉 ) ]的回交后代 BC4F1 发生疯狂分离 ,在各个性状上都表现出特殊的变异类型 ,在育性上分离出三种类型 :可育株 ,部分可育株 ,不育株。对这三种类型和三元杂种 F1 花粉母细胞减数分裂的观察表明 ,三元杂种 F1 及回交后代的不育株减数分裂表现异常 ,大多染色体不能联会配对 ,以单价体的形式存在 ,且有落后染色体、三价体、四体环的出现 ,在末期形成了不正常的四分孢子和多分孢子 ,这是不育的主要原因 ;部分可育株 ,大部分染色体联会配对成棒状二价体 ,个别为单价体 ;可育株染色体配对正常 ,能形成可育的花粉粒 BC4F1, a backcrossing offspring of ternary hybrid [cotton × (Asiatic cotton × Bk cotton)], was wildly separated and showed special variations in all traits. Three types of fertility were isolated: fertile Strain, partially fertile plants, sterile plants. The observation of the meiosis of F1 pollen mother cells of these three types and three hybrids showed that the meiosis of the sterile F1 plants and the backcross progeny of the three hybrids showed abnormalities and most of the chromosomes could not be paired. Exist, and there are backward chromosomes, trivalent body, four-body ring appear in the late formation of abnormal tetradospores and polypospores, which is the main reason for infertility; part of the fertile plants, most of the chromosome association will be paired Into bar-like bivalent, individual monovalent; fertile chromosome pairing normal, can form fertile pollen