利用RAPD标记研究中国芥菜型油菜遗传多样性

利用ＲＡＰＤ标记，对以我国西北和西南为主的６８个芥菜型油菜地方品种和４个加拿大引进品种（系）的遗传多样性进行了研究。通过３１个随机引物的ＲＡＰＤ分析，表明选用的７２个品种（系）间存在广泛的遗传变异，多态性位点比率达８５．３１％。经ＵＰＧＭＡ聚类分析将它们划分为６大类群，从聚类图可得如下结论：（１）地理差异和生态环境对遗传差异有重要影响，即来自同一省份的品种基本上聚在同一类群中。（２）我国冬播和春播

GENETIC DIVERSITY OF CHINESE LANDRACES IN Brassica napus WAS ANALYSED BY RAPD MARKERS

This paper presented the exent of genetic diversity of 68 Chinese landraces of Brassica juncea and 4 Canadian lines by RAPD markers. A total of 211 DNA bands were observed with 31 arbitrary 10 - base primers and 180 of them were polymorphic. Average proportion of polymorphic lori was 85. 31%. Abundant genetic diversity were found within landraces and lines. On the basis of the gentic distance, a phylogenetic tree was constructed by UPG-MA. All of them were divided into 6 groups. It was shown that the geographic distribution and ecological environment was one of the important fartors affecting the extent of genetic diversity. Genetic differences existed both between and within winter landraces and spring's in B. juncea. Greater genetic diversity was found within winter B. juncea than within spring' s. High similarity was revealed among Hubei, Jiangsu and Guizhou landraces. Small genetic distances were observed between Henan and Shaanxi landraces. All the above areas have winter B. juncea. In some spring B.juncea places, for example, Shanxi and Gansu, their landraces had also close relationship. Another result was that there was very close relationship between spring landraces of Xinjiang Autonomous Region of China and the Canadian B. juncea breeding lines. These results provided valuable information for properly selecting parents of crosses and en-hancing breeding efficiency. The paper also discussed the influence of the number of arbitrary primers on the extent of genetic diversity. Comparing the phylogenetic tree constructed by 31 arbitrary primers with the other tree based on 23 primers with over 80% polymorphic locus rates, both bees had a high similarity. It is proved that a higher rate of polymorphic loci for assessing genetic diversity is more informative than more arbitrary primers.