Karyotype and resemblance-near coefficient analysis of （ Gossypium arboreum × G. bickii ） and tri-specific hybrids | 亚比棉及其与陆地棉、海岛棉种间杂交种的核型及似近系数聚类分析

中国人. 为将原产澳洲的棉属野生种比克氏棉（Gossypiumbickii）具有的子叶腺体延缓形成基因导入栽培种，将亚洲棉（G．arboreum）与比克氏棉（G．bickii）杂交，并经染色体加倍，获得亚比棉异源四倍体，然后再用异源四倍体与陆地棉（G．hirsutum）、海岛棉（G．barbadense）杂交获得具有[ADG]3个染色体组的三种杂种。本研究以三种杂种与其亲本为材料，对参试材料进行核型分析，并采用核型似近系数聚类分析方法对参试材料进行聚类分析。研究结果表明：亚比棉染色体的相对长度小于亚洲棉和比克氏棉，且变异范围较小，亚比棉的LC／SC值高于亲本亚洲棉和比克氏棉；亚比棉×陆地棉和亚比棉×海岛棉的LC／SC值比任一亲本均高。亚比棉的臂比均值最小，核型最为对称，为1A。核型聚类结果表明，陆地棉和海岛棉的核型似近系数最大为0．9958，核型进化距离为0．0042，亲缘关系最近。比克氏棉和亚比棉的核型似近系数最小为0．6483，核型进化距离为0．4334，亲缘关系最远。

英语. Gossypium bickii from Australia has a special trait, with gossypol appearing only after the formation of the cotyledon. In order to transfer.such useful trait of G. bickii into cultivars and improve its economic returns,the amphidiploid was obtained from G. arboreum x G. bickii ,then some tri-specific hybrids were derived from （G. arboreum x G. bickii） x G. hirstum , （ G. arboreum × G. bickii ）× G. barbandense in Shanxi Agricultural University. The tri-specific hybrids and their parents were analyzed in karyotype,and clustered by the karyotype resemblance-near coefficient aimed to establish a genetic link for all the materials. We showed that the relative length of the chromosomes from amphidiploid G. arboreum x G. bickii was smaller than that of chromosomes of G. arboreum and G. bickii with a limited change range. The LC/ SC value of amphidiploid G. arboreum x G. bickii was higher than that of the G. arboreum and G. bickii;and the LC/ SC value of （ G . arboreum x G . bickii ） x G . hirstum and （ G. arboreum x G . bickii ） × G . barbandense were the highest among all the parents. The karyotype of amphidiploid G. arboreum x G. bickii was 1A with the least arm ratio. Cluster analysis showed that the closest genetic relationship was G. hirstum and G. barbandense astheir karyotype resemblance-near coefficiency was the highest, namely 0. 995 8, their evolution distance was 0. 004 2. On the contrary, the farthest genetic relationship was G. bickii, and amphidiploid G. arboreum x G. bickii, with the lowest karyotype resemblance-near coefficiency, namely 0. 648 3,and their evolution distance was 0.433 4.