小麦纹枯病抗源的遗传多样性及抗性基因位点SSR标记分析

Genetic Diversity of Wheat Germplasm Resistant to Sharp Eyespot and Genotyping of Resistance Loci Using SSR Markers

为揭示小麦纹枯病抗源的遗传多样性,发掘优异的抗性种质,利用沟带接种法对前期筛选出的88份抗性种质进行了3年田间抗性鉴定,鉴定出抗或中抗纹枯病的小麦种质32份。利用分布于全基因组的SSR标记对这些抗源进行了遗传多样性分析,59个SSR标记共检测到308个等位变异,每个标记可以检测到2~13个等位基因,平均5.2个；多态性信息含量（PIC）的变异范围为0.12~0.89,平均为0.61,表明材料的遗传丰富度较高。根据聚类分析和主成分（PCA）分析,32份小麦纹枯病抗源按照遗传相似系数可划分为2个组群,国外引进品种和国内改良品种聚为一类,国内农家品种聚为一类,并且与地理分布特征相符。利用与纹枯病抗性QTL紧密连锁的14个SSR标记对32份抗源进行基因型分析,发现与抗性QTL连锁的2BS上的Xwmc154和7DS上的Xbarc126普遍存在,可用于分子标记辅助选择。在武农148、陕983、陕农78、Coker 983、H-Line、Mason和Compair中仅检测到一个已报道的抗病QTL,而在Tyalt中没有检测到已知抗病QTL,这些材料有可能携带新的纹枯病抗性基因/QTL,可以在育种中加以利用。

A three-year filed identification with artificial inoculation was carried out to validate 88 wheat germplasm resources resistant to sharp eyespot identified in previous studies. Thirty-two accessions showed resistance or moderate resistance to sharp eyespot. Rich genetic diversity among these resistant resources was revealed by 59 SSR markers across the whole wheat genome. A total of 308 alleles were detected with 2–13 alleles per marker and an average of 5.2. The polymorphism information content （PIC） ranged from 0.12 to 0.89 with an average of 0.61. The clustering and principal component analysis （PCA） based on mo-lecular marker data indicated that the 32 resistant accessions were grouped in improved variety （including alien varieties） and landraces, which was consistent with geographic distribution. The 32 resistant varieties were genotyped with 14 SSR markers closely linked to QTLs for sharp eyespot resistance.Xwmc154 on 2BS andXbarc126 on 7DS were frequently detected in the re-sistant resources. As a consequence, they are recommended in marker-assisted selection. Only one known resistance QTL was detected in varieties Wunong 148, Shaan 983, Shaannong 78, Coker 983, H-Line, Mason, and Compair, whereas no resistance QTL was found in Tyalt. These varieties might carry novel resistance genes/QTLs against wheat sharp eyespot and are promising in wheat breeding.