应用RAPD和AFLP标记的方法对甜(辣)椒和番茄品种的多态性分析

应用RAPD和AFLP的DNA指纹图谱方法分析25个甜(辣)椒和22个番茄品种的真实性，并进一步比较RAPD和AFLP的DNA指纹图谱在鉴定亲缘关系较近的品种之间的真实性时的有效性。对于甜(辣)椒品种，AFLP方法中，2个引物组合扩增反应的多态性片段即能将25个品种完全分开。虽然，每个样品的AFLP的扩增产物中多态性片段的百分率为9％，低于RAPD的35％多态性片段的百分率。但是，AFLP的信息量远远大于RAPD的信息量，它的每对引物组合扩增的平均多态标记为5．1，而RAPD仅为2．2。所以，在甜(辣)椒的指纹图谱中，AFLP的有效率是RAPD的2倍。对于番茄品种，每个样品的AFLP的扩增产物中多态性片段的百分率为5．5％，大大低于RAPD的单引物61％多态性片段和双引物58％多态性片段的百分率。它的每对引物组合扩增反应的平均多态标记为2．6，而RAPD中，单引物扩增的平均多态标记为4．2，双引物扩增的平均多态标记为4．4。一个单引物和一个双引物的RAPD扩增反应的多态性片段即能将22个番茄品种中的21个完全分开。所以，在番茄的指纹图谱中，RAPD的有效率是AFLP的2倍。因此，在应用分子标记辅助鉴定品种的真实性时，不同的作物所适用的方法是不同的。

Variation in Some Lycopersicon esculentum and Capsicum annuum Cultivars Revealed by RAPD and AFLP Markers

Twenty-five accessions of pepper(Capsicum annuum) and twenty-two accessions of tomato (Lycopersicon esculentum) cultivated in primary province where the main agricultural breeding insititutes breed the majority improved varieties of pepper and tomato in China were analysed.RAPD and AFLP markers were performed and compared for their effectiveness to discriminate near relatives.In pepper varieties,AFLP markers generated by two primer combinations distinguished every pepper accessions.The percentage of polymorphic markers for AFLP was lower than that for RAPD(9% and 35% respectively).However,the average numbers of polymorphic fragments were 2.2 per primer for RAPD and 5.1 per AFLP primer combination,respectively.Therefore AFLP primers were two times more efficient than RAPD primers in their ability to generate polymorphic markers in pepper varietes.In tomato varieties,the percentages of polymorphic markers were 5.5% for AFLP and 61% for RAPD single primer and 58% for RAPD two-primer,the percentage of polymorphic markers of AFLP was lower than that for RAPD.The average numbers of informative bands per primer were 4.2 for RAPD single primer and 4.4 for RAPD two-primer and 2.6 for AFLP primer combinations,respectively.The study demonstrated that RAPD markers were more useful than AFLP markers among nearly related tomato varieties.RAPD markers generated by one single primer and one two-primer reactions can discriminate 21 out of 22 tomato varieties.The effectiveness of various marker techniques for the two species C.annuum and L.esculentum is discussed.