中国芝麻主要品种遗传多样性特点及遗传基础演变

 【目的】探明中国主要芝麻品种遗传多样性特点和遗传基础演变趋势。【方法】采用SRAP（Sequence- related amplified polymorphism,相关序列扩增多态性）标记对中国芝麻主要产区1950－2007年间应用的67个品种进行分析。【结果】21对SRAP随机组合引物共扩增DNA带561条,多态性带265条,比例为47.2%;每对引物平均扩增的总带数和多态性带分别为26.7和12.6条。67个品种间的遗传相似系数平均为0.9104,遗传距离平均为0.0706,遗传多样性较匮乏,遗传基础较窄。地方品种与杂交选育品种间的遗传相似系数和遗传距离的均数差异达到极显著水平,前者的遗传基础较后者宽;1990－2007年间应用的品种遗传基础较1950－1969年和1970－1989年间的窄,其遗传相似系数和遗传距离的均数差异均达到极显著水平。【结论】中国芝麻主要品种总体遗传基础较窄,近年来通过杂交选育的品种遗传基础较历史品种狭窄。

Analysis on Genetic Diversity and Genetic Basis of Main Sesame Cultivars Released in China

【Objective】 The aim of the experiment is to investigate the genetic diversity and genetic basis of main sesame cultivars in China. 【Method】 SRAP (Sequence-related amplified polymorphism) was used for the analysis of 67 sesame cultivars widely used in China’s sesame major production areas from 1950 to 2007. 【Result】 A total of 561 bands were amplified using 21 SRAP random primer pairs, with 265 of them were polymorphic, resulting a polymorphism ratio of 47.2%. The total bands and polymorphism amplified by each primer pair averaged 26.7 and 12.6, respectively. The average genetic similarity coefficient and genetic distance of the 67 cultivars were 0.9104 and 0.0706, respectively, indicating limited genetic diversity and narrow genetic basis. Comparative analysis on genetic similarity and genetic distance of different classified cultivars showed that the difference of average genetic similarity coefficient and genetic distance between the landraces and cultivars bred through crosses reached a significant level (P=0.01), with the genetic basis of landraces wider than that bred cultivars. The genetic basis of cultivars used in 1990-2007 was more narrow than that of cultivars from 1950 to 1969 and from 1970 to 1989, with the differences of average genetic similarity coefficient and genetic distance reached a very significant level. 【Conclusion】 The genetic basis of main sesame cultivars in China is relatively narrow, and the genetic basis of cultivars developed through crosses in recent years is more narrow than history cultivars.