用EST-SSR标记检测我国甘蓝型油菜品种的遗传多样性

Genetic diversity in Chinese rapeseed (Brassica napus) cultivars based on EST-SSR markers

杂交育种依然是我国油菜育种的主要方法,杂种优势的利用仍然是提高产量的重要途径。为了解我国甘蓝型油菜的遗传变异,采用16个EST-SSR标记对近年来推广的91个品种的遗传多样性进行了分析。共扩增到100个条带,其中84个多态性带,多态性比率为84%。平均每对引物扩增的带数和多态性带数分别为6.25个和5.25个。多态性信息含量(PIC)变化在0.022–0.926之间,平均为0.677,所揭示的基因型数变化于2–24之间,平均为12.44个。供试材料间遗传距离变幅较大(0.0530–0.7223之间),说明它们具有广泛的遗传变异。其中,杂交种和2000年以后育成品种的遗传基础较宽,遗传多样性分别明显高于常规品种和2000年以前育成的品种。按非加权成对平均数法(UPGMA)进行的聚类分析显示,在遗传距离为0.313处,参试材料可以分为三大类,其中,包含87份材料的第一大类在遗传距离为0.233处又可进一步分为10个亚类。聚类结果与系谱来源基本一致,比较真实反映了所用材料的遗传变异情况。

In order to assess genetic variation in Chinese rapeseed （Brassica napus）, the genetic diversity of 91 cultivars released in recent years was assessed using EST-SSR markers. In total, 100 amplified fragments were detected using 16 EST-SSR primer pairs; of these fragments 84 were polymorphic. The number of amplified and polymorphic fragments was 6.25 and 5.25 per primer pair, respectively. The PIC （polymorphism information content） value of these markers varied from 0.022 to 0.926, averaging 0.677. The genotypes revealed by each marker ranged from 2 to 24 with average of 12.44. Genetic distance （GD） varied widely, from 0.0530 to 0.7223, suggesting the presence of broad genetic variation in the accessions we used. Diversity was higher in hybrid varieties and varieties released after the year 2000 than in traditional open-pollinated varieties and varieties released before or during the year 2000, respectively. At GD = 0.313 the tested varieties could be classified into three groups clustered by UPGMA, in which the first group containing 87 cultivars could be further divided into 10 sub-groups at GD = 0.223. The cluster results generally agreed with pedigree analysis and reveal the true genetic variation in the materials tested.