甘蔗常用亲本及优良组合双亲间遗传相似性分析

Analysis of Genetic Similarity among Commonly-Used Sugarcane Parents and between two Parents of Cross

采用18对SSR引物和15对AFLP引物对我国196份甘蔗常用亲本的遗传相似性进行分析,分别获得438和1192个标记,多态性位点比例分别是87.60%,80.80%,平均为84.2%;亲本遗传相似系数变幅介于0.4761～0.9099之间,总平均值为0.6673,遗传差异处于中等水平的亲本占了大多数,而差异较小和较大的都只是少数;45个甘蔗品种亲系的遗传相似系数分布在0.5687～0.6723,平均值为0.6723,91.11%甘蔗品种亲系的遗传相似系数集中在0.6100～0.7300之间,较理想的甘蔗杂交组合亲本间的遗传相似系数应为0.6723±0.0600;聚类分析表明,以遗传相似系数阈值约为0.700划分,育出45个品种所使用的30个亲本可分为9大类,在不同类型间选择亲本搭配的组合更容易选育出优良品种。

SSR and AFLP were employed to estimate genetic similarity among 196 sugarcane parents in common used. 18 SSR primer combinations produced a total of 438 bands, 87.60% of which were polymorphic, whereas 15 AFLP primer combinations produced a total 1 192 bands, 80.80% of which were polymorphic. The overall average rate ofpolymorphic loci was 84.2%. The genetic similarity index （GSI） among 196 parents estimated ranged from 0.476 1 to 0.909 9 with an average of 0.667 3. Most of the GSI between two parents were moderate, whereas a few of them were high or low. GSI among several decades couples of parents developed 45 varieties analyzed ranged from 0.568 7 to 0.672 3 with an average of 0.672 3, 91.11% of which ranged from 0.610 0 to 0.730 0, implying that GSI between two parents for making a cross should be in the scope of 0.672 3±0.060 0. The 30 parents having produced 45 varieties were clustered into nine groups at 0.700 of the GSI value. The results indicated that it would be easier to develop good varieties when making a cross with parents from different groups.