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本文首次对5个陆地棉三体的起源、形态及减数分裂中期Ⅰ的染色体构型进行了研究。辐射造成染色体提早解离和染色体不分离是形成三体的细胞学基础。对5个三体的细胞学分析表明:Ftr-2是次级三体,Ftr-4可能是三级三体,Ftr-1,Ftr-3和Ftr-5是初级三体。它们减数分裂时形成三价体的频率为0～41.67％。Ftr-2和Ftr-5具有明显的形态特征,可以根据形态对其进行准确鉴定。通过对Ftr-5与易位系杂交后代三体株的细胞学研究表明:Ftr-5的额外染色体不是A染色体亚组中的第1、3、6、8、10、11、12和13染色体,也不是D染色体亚组中的第14、15、16、19、23和24染色体。三体中其它染色体的易位会降低三体中三价体形成的频率。
In this paper, the origin, morphology and chromosome configuration of metaphase Ⅰ in five upland cotton genotypes were studied for the first time. Radiation caused chromosome premature dissociation and chromosome segregation is the formation of three body cytology. Cytological analysis of five trisomies showed that Ftr-2 is a trisomy, Ftr-4 may be trisomy 3, and Ftr-1, Ftr-3 and Ftr-5 are primary trisomies. The frequency of triad formation during meiosis ranged from 0 to 41.67%. Ftr-2 and Ftr-5 have obvious morphological characteristics, which can be accurately identified according to the morphology. Cytological studies of the trisomy of hybrid progeny of the Ftr-5 and the translocation lines showed that the additional chromosome of Ftr-5 was not the chromosomes 1, 3, 6, 8, 10, 11, 12 and 13 of the A chromosome subgroup , Nor the 14th, 15th, 16th, 19th, 23th and 24th chromosomes in the D chromosome subgroup. The translocation of other chromosomes in the trisomy reduces the frequency of trivalent formation in the trisomy.