90份鳄梨种质资源AFLP遗传多样性分析

AFLP Molecular Markers-based Genetic Diversity Analysis on 90 Avocado Germplasms

【目的】本研究对采自中国云南德宏、保山、西双版纳、普洱、红河和缅甸克钦邦、掸邦地区共90份鳄梨种资资源进行遗传多样性分析,为其新品种选育和种质创新提供参考依据。【方法】采用CTAB法提取鳄梨叶片基因组DNA,利用扩增片段长度多态性分子标记技术,对90份种质资源的基因组DNA进行酶切、连接、预扩增、选择性扩增,电泳分离,银染显色。电泳结果得到"0,1"矩阵,使用POPGENE 32软件计算每对引物的多态性条带、多态性比率、有效等位基因数、遗传多样性指数等指标,同时使用NTSYSpc-2.11F计算种质间遗传相似系数,根据相似性系数进行UPGMA聚类分析和PCA主效应分析,对鳄梨种质资源进行分类。【结果】从24对AFLP引物组合中,筛选出8对扩增条带清晰、多态性高的引物组合,8对引物共扩增出1 165个条带,其中多态性条带有1 163个,多态位点百分率为99.83%;有效等位基因数(Ne)平均1.294 4个;Nei’s基因多样性指数(H)平均0.209 5;Shannon信息指数(I)平均0.353 0。根据遗传相似系数进行聚类分析,在遗传相似系数0.752处可划分为4个类群,第Ⅰ类群有1份保山种质70号;第Ⅱ类群有24份种质;第Ⅲ类群有1份西双版纳种质59号;第Ⅳ类群有64份种质。在遗传相似系数0.763处可将第Ⅳ类群划分为3个亚群(A、B和C)。用PCA法对90份鳄梨种质AFLP标记结果进行主效应分析,显示了不同种质的分类位置,主效应分析结果与分子聚类结果基本一致,呈一定的地域性分布规律。【结论】90份种质资源的遗传多样性较为丰富,59号和70号相对特殊,在种质创新中应给予重点关注。

【Objective】 Genetic relationship of 90 avocado(Persea americana Mill.) germplasms collected from Dehong,Baoshan, Xishuangbanna, Puer, and Honghe in Yunnan, China and Shan and Kachin States of Burma was analyzed based on AFLP molecular markers for breeding reference and resource information. 【Method】 Genomic DNAs were extracted from the leaves of the avocado plants following the CTAB method. They were amplified using the sequence-related amplified polymorphism molecular markers to determine their genetic diversity and similarity. Separation of the amplified fragments was performed on 5% denaturing polyacrylamide gels stained with Ag NO3 to obtain the "0,1" matrix. The number of polymorphic loci, percentage of polymorphic loci, effective number of alleles, and indices of genetic diversity were estimated by POPGENE version 32. The genetic similarity estimated by NTSYSpc-2.11 F was used for UPGMA(unweighted pair group methodanalysis) and PCA(principal component analysis) to classify the avocado germplasms. 【Result】 Eight primers with strong polymorphism and high repeatability were screened from 24 AFLP primers generating a total of 1 165 bands. Of the bands,1 163(99.83%) showed polymorphism. On average, the number of effective alleles was 1.294 4;Nei’s gene diversity(H),0.209 5;and Shannon’s information index(Ⅰ), 0.353 0. At the genetic similarity index(GS) of 0.752, the germplasms were classified into 4 groups. A single avocado germplasm, No. 70, collected from Baoshan was placed in Group Ⅰ. Group Ⅱ had 22 germplasms;Group Ⅲ, one germplasm, No. 59, from Xishuangbanna;and Group Ⅳ, the 64 remainders. The germplasms in Group Ⅳ were further divided into Subgroups A, B and C at GS of 0.763. A similar grouping result was obtained from the cluster analysis on the PCR data applied AFLP markers confirming these germplasms shared a high similarity within a same region. 【Conclusion】 The 90 collected avocado germplasms were found to be relatively high in genetic diversity. Among them, No. 59 and 70 stood out as two most unique varieties.