芝麻野生种Sesamum alatum与栽培种Sesamum indicum核型比较分析

Karyotype Comparison Analysis of the Wild Species Sesamum alatum and the Cultivated Sesame

采用酶解去壁低渗法首次对芝麻栽培种(Sesamum indicum)国内外34份种质资源及野生种(Sesamum alatum)进行了体细胞染色体特征观察以及核型分析与比较.染色体形态观察研究证实S. indicum(2n=26)染色体组中含有3对随体染色体,野生种S. alatum(2n=26)染色体组中含有1对随体染色体.在S. indicum34份种质中,核型公式多为2n=2x=26=10m+14sm+2st(例如var.豫芝11号),其中22份种质的染色体组为2A类核型,12份为3A类核型.野生种S. alatum(var.3651)核型公式为2n=2x=26=10m+12sm+4st,染色体组属于3A类核型.染色体相对长度分析结果表明,芝麻栽培种与野生种S. alatum的染色体多为中等染色体(M1和M2类型),相对长度组成公式分别为12M2+12M1+2S(var.豫芝11号)和2L+10M2+12M1+2S(var. 3651).比较分析结果表明,野生种S. alatum染色体组不对称性高于多数芝麻栽培种种质,该研究为进一步探明芝麻物种进化提供了细胞遗传学证据.

In order to explore the characteristics of the chromosomal evolution in Sesamum, we observed the characteristics of the chromosomes in the wild species Sesamum alatum and 34 worldwide germplasm resources of sesame cultivars（Sesamum indicum） through the wall degradation hypotonic method in chromosome preparation for the first time, and performed the karyotype comparison analysis within the 35 samples in this article. The results of chromosome morphology observation confirmed that 3 pairs of satellite chromosomes exist in S. indicum（2 n=26）, while only 1 pair of satellite chromosomes exist in S. alatum（2 n=26）. In most of 34 germplasm of S. indicum, the karyotype formula is 2 n=2 x=26=10 m＋14 sm＋2 st（i.e., var. Yuzhi 11）. 22 samples belong to 2 A karyotype, while the other 12 samples belong to3 A karyotype. In S. alatum, the karyotype formula is 2 n=2 x=26=10 m ＋ 12 sm ＋ 4 st, and belongs to 3 A type. Relative chromosome length analysis showed that most of the chromosomes of the 35 materials belong to moderate-size types of M1 and M2,and the formula of relative chromosomal length is 12 M2＋12 M1＋2 S（var. Yuzhi 11） and 2 L＋10 M2＋12 M1＋2 S（var. 3651） respectively. Comparative analysis reflected that the chromosome asymmetry of S. alatum is higher than most of the tested materials of S. indicum. The results provide the cytogenetic evidences for further research of the Sesamum evolution.