西藏白菜型黄籽油菜地方品种的核型分析

Karyotype study of yellow-seed rape landraces(Brassica rapa L.) of Tibet China

为研究西藏白菜型黄籽油菜遗传种质特性的细胞学信息,选取8份西藏白菜型黄籽油菜地方品种为材料,采用常规压片法进行核型分析,并利用染色体主要核型参数进行进化和聚类分析。结果表明：供试材料的染色体数目一致,均为2n=20,染色体均由中部着丝粒染色体（m）和亚中部着丝粒染色体（sm）组成,均带有1对随体。核型类型均为对称型2A型。染色体形态结构存在一定的差异,染色体长度比变幅为1.60~1.91,平均臂比为1.33~1.52,不对称指数介于56.08%~58.85%之间。以核型不对称性评定参试材料进化程度,塔巴寺黄籽的进化程度最高,夏鲁寺黄籽的进化程度最低;核型特征聚类将8份材料分为3组。进化和聚类分析发现,西藏白菜型黄籽油菜进化速度较慢,在系统演化过程中处于较为原始的地位。

To gain more information of the cytological of Tibetan yellow-seed rape（Brassica rapa L.）,8yellow-seed rape landraces from Tibet China were selected and performed by tabletting observation based on karyotypic parameters. Results showed that each material had 20 chromosomes composed by median region chromosomes（m） and sub-median region chromosomes（sm） with a pair of satellites. Their karyotype belonged to 2A type. Their chromosome morphology was different. The differences included Lt/St（1. 60-1. 91）（with average arm ratio of 1. 33-1. 52） and asymmetry index from 56. 08% to 58. 85%. According to karyotype dissymmetry coefficient,their evolution degree showed that Taba Monastery yellow-seed was the highest,and Xialu Monastery yellow-seed was the lowest. 8 landraces could be divided into 3 groups by karyotype features. Evolution and cluster analysis results showed that the evolutionary rate of yellow-seed rape landraces from Tibet was slow. These landraces were still at their original evolutionary stage.