棉属野生种稀毛棉、皱壳棉、杨叶棉的核型研究

Studies on Karyotypes of Gossypium pilosum, G.costulatum and G.populifolium

本文研究了原产澳大利亚的稀毛棉（Ｇ．ｐｉｌｏｓｕｍ）、皱壳棉（Ｇ．ｃｏｓｔｕｌａｔｕｍ）、杨叶棉（Ｇ．ｐｏｐｕｌｉｆｏｌｉｕｍ）的核型。稀毛棉的核型公式为２ｎ＝２ｘ＝２６＝１６ｍ（４ｓａｔ）＋１０ｓｍ，皱壳棉为２ｎ＝２ｘ＝２６＝１６ｍ（４ｓａｔ）＋１０ｓｍ，杨叶棉为２ｎ＝２ｘ＝２６＝１８ｍ（４ｓａｔ）＋８ｓｍ。随体均有两对，一对位于第１１对染色体的长臂上，另一对位于第１３对染色体的短臂上。平均臂比和长度比分别为稀毛棉１．５３和２．５１、皱壳棉１．５５和２．３１、杨叶棉１．４９和２．３７，其核型均属于Ｓｔｅｂｂｉｎｓ的２Ｂ类型。对称系数稀毛棉为２６．０４，皱壳棉为２７．９３，杨叶棉为２８．３２。三者彼此之间的核型重合率均在９０％以上。

Karyotype analysis was carried out on wild Gossypium species, including G.piloson, G.costulatum and G.populifolium in sect. Grandicalyx origining from Australia. The karyotypic formula is 2n=2x=26=16m(4sat)+10sm in G.pilosum, 2n=2x=26=18m(4sat)+8sm in G.costulatum, 2n=2x=26=16m(4sat)+10sm in G.populifolium, respectively. There are four satellites in every species, being located on the longer arm of the 11th pair chromosomes and the shotter arm of the 13th pair chromosomes. Mean arm ratios (Mar) and length ratios (Lr) are 1.53 and 2.51 in G.pilosum, 1.55 and 2.31 in G.costulatum, 1.49 and 2.37 in G.populifolium. Their karyotypes are of Stebbins'2B. Symmetry index (Si) of G.pilosum, G.costulatum, G.populifolium is 26.04, 27.93 and 28.32, respectively. Overlaping percentages (Op) are all above 90% each other. Karyptypic homogeny showed that the three species are very similar in origin.