中国食用向日葵种质资源遗传变异的RAPD及AFLP分析

本研究采用RAPD和AFLP方法对23个中国不同地区的食用向日葵（Helianthus annuus L.)骨干品种进行了遗传变异分析，同时对两种标记系统进行了比较。26个RAPD引物产生了总计192条DNA条带，大小分布 于0.26kb-1.98kb之间，其中165条（86．12％）具有多态性，每条引物产生DNA条带的平均数为7．38。8对AFLP引物组合共产生了576条带，分布于100bp-500bp之间，其中的341条具有多态性，多态百分率为76．00％，每对引物组合产生DNA条带的平均数为72。RAPD方法检测的每位点有效等位基因数（1．76）大于AFLP（1．65），AFLP标记位点的平均多态性信息量（PIC）（0．38）低于RAPD标记位点PIC（0．41），但AFLP标记具有很高的多态性检测效率（Ai=38．52）。用RAPD标记分析23个食用向日葵材料的亲缘关系，Nei氏相似性系数分布在47．84％－82．06％，平均相似性系数为0．6495，而采用AFLP的Nei氏相似性系数分布在54．15％－83．52％，平均相似性系数为0．6884。RAPD数据的标准差为0．13，而AFLP数据的标准差为0．08。因此，采用RAPD和AFLP方法分析食用向日葵遗传变异，RAPD标记具有较低相似性系数和较高方差而AFLP则相反。源于两种不同标记的遗传相似矩阵的相关系数为0．51，说明采用RAPD和AFLP系统分析食用向日葵遗传变异得到的结果有一定的相关性，无论采用RAPD还是AFLP标记进行聚类分析，都将23个不同基因型的食用向日葵材料分成了三个类群。

Comparison of Genetic Diversity of the Germplasm Resources of Confectionary Sunflower (Helianthus annuus) in China Based on RAPDs and AFLPs

RAPDs and AFLPs were used to determine the genetic relationships among 23 elite cultivars of confectionary sunflowers (Helianthus annuus) from different districts in China. Both approaches uniquely fingerprint each of the accessions. Twenty_six RAPD primers resulted in a total of 192 strong DNA fragments, ranging from 0.26 kb to 1.98 kb, among which 165 (86.12%) were polymorphic. The average number of DNA band produced by each primer was 7.38. A total of 576 AFLP markers were produced with 8 primer combinations, ranging from 100 bp to 500 bp, and 341 polymorphic bands (59.20%) were revealed. The polymorphism rate was 76.00% and the average bands amplified by per primer combination were 72. Effective number of alleles per locus of RAPD marker (1.76) was larger than that of the AFLP marker (1.65). The mean PIC value of AFLP markers (0.38) was lower than that of the RAPD markers (0.41), but AFLP marker had much higher Ai value (38.52) than RAPD marker (6.38). Genetic similarities from RAPD data ranged from 47.84% to 82.06% and the average Nei's coefficient was 0.649 5; the Nei's coefficient of similarity from AFLP data ranged from 54.15% to 83.52%, and the average Nei's coefficient was 0.688 4. However, standard deviation ( SD ) of RAPDs was 0.13 but the SD of AFLPs was 0.08. In general, the RAPD data gave lower similarity values and higher SD values than those based on the AFLP analysis. The correlation coefficient between the two genetic similarity matrices was 0.51, revealing the estimations of genetic relationship provided by the two marker systems were only moderate. However, cluster analyses of RAPD or AFLP data divided the 23 sunflower genotypes into identical 3 groups.