Genetic Diversity of Maize (Zea mays L.) Landraces from Southwest China Based on SSR Data  

我国西南地区玉米地方品种遗传多样性的SSR分子标记分析(英文)

作　　者：姚启伦[1] 杨克诚[1] 潘光堂[1] 荣廷昭[1] 

机构地区：[1]四川农业大学玉米研究所

出　　处：《Journal of Genetics and Genomics》2007年第9期851-860,共10页遗传学报（英文版）

基　　金：This work was supported by the National High Technology Research and Development Program of China (No. 2004BA525B04);Changjiang Scholars and Innovative Research Team in University (No. IRTO453).

摘　　要：Genetic diversity of 54 maize landraces from southwest China was tested using bulk DNA samples and 42 microsatellite （SSR） loci distributed on 10 chromosomes of maize. A total of 256 alleles were detected among the landraces. At each locus, the number of alleles varied from 2 to 9, with an average of 6.1. On the basis of the genetic similarity coefficients, clustering analysis separated the landraces into four groups. The landraces collected from the same region were mostly grouped together. To reveal the genetic structure and genetic diversity within landraces, 165 individuals from 11 landraces were analyzed. Individual DNA samples proved to be superior to bulk DNA samples in identifying genetic diversity of landraces. A total of 330 alleles were detected in the 11 landraces. According to the results of the individual DNA sampling analysis, estimates of the mean number of alleles ‘A’, the effective allelic number ‘Ae’, the observed heterozygosity ‘Ho’, and expected heterozygosity ‘He’ were 7.86, 3.90, 0.69, and 0.37, respectively. An obvious genetic deviation from Hardy-Weinberg expectation was observed both among and within landraces and a considerable genetic variation was revealed within rather than among landraces. In addition, genetic diversity of landraces was greater in Sichuan than in the other three regions. It can be concluded that maize landraces in southwest China were initially introduced to Sichuan and from there to adjacent areas.利用微卫星(SSR)标记技术和DNA混合取样方法,选取均匀覆盖玉米染色体组的42对SSR引物,检测了来自我国西南地区54个玉米地方品种的遗传多样性。在54个玉米地方品种中检测到256个等位基因,每个SSR标记的等位基因数为2～9个,平均6.1个,说明我国西南地区玉米地方品种遗传多样性丰富。根据遗传相似系数矩阵做出的树状图,将54个玉米地方品种大致划分成4类,来源于同一地区的多数玉米地方品种划分在同一类中,表明西南地区玉米地方品种的地理分布与其遗传背景存在内在联系。从54个玉米地方品种中选出11个,每个品种选取15个单株,共165个DNA单株样品,分析玉米地方品种的遗传结构及其品种内的遗传多样性。对于检测玉米地方品种的遗传多样性,DNA单株样品分析优于DNA混合样品分析,42对相同的SSR引物在11个玉米地方品种中检测到330个等位基因,平均等位基因数A=7.86,有效等位基因数Ae=3.90,平均期望杂合度He=0.69,实际观察杂合度H0=0.37。据遗传结构分析结果,固定指数(F)为0.25～0.79,表明玉米地方品种是典型的混合繁育系统;由于杂合体不足,玉米地方品种群体间及群体内的遗传结构均偏离了Hardy-Weinberg平衡;杂合性基因多样度比率(Fst)平均为0.07,表明品种间和品种内的遗传变异分别占总遗传变异的7%和93%。玉米地方品种内遗传多样性及品种间遗传距离分析结果表明,在我国西南地区,分布在四川的玉米地方品种具有最丰富的遗传变异。经综合分析推测,我国西南地区玉米地方品种最早引进到四川种植,由此向毗邻地区传播扩散。

关 键 词：genetic diversity maize landraces SSR 

分 类 号：S513[农业科学—作物学]