小麦白粉病是由小麦白粉菌(Erysiphe graminis f.sp.tritici)引起的气传性真菌病害，它是影响世界各国小麦生产的重要病害之一。近年来，白粉病在我国小麦生产中有逐渐加重的趋势，已成为威胁我国小麦生产安全的主要病害，对我国粮食安全构成了巨大的威胁。实践证明，选育抗病品种是防治小麦白粉病最经济、有效和安全的手段。小麦近缘种属已成为白粉病新抗病基因非常重要的来源(Pm30～Pm43)，这些抗病基因多为质量抗性，对当前流行的生理小种有较好的抗性。但这类抗源往往与不利的农艺性状相连锁，作为抗源导入栽培品种时，后代需要经过多代回交来打破与不利基因的连锁，有的甚至经过多代回交以后仍无法打破这种连锁，这在很大程度上制约了此类抗源在育种中的应用。普通小麦特别是主栽品种中所携带的抗病基因由于其载体具有很好的综合农艺性状，在生产上具有很高的实际应用价值。 周98165作为一个综合性状优良的小麦品种，对河南省当前流行白粉菌生理小种具有较好的抗性，本试验通过对抗白粉病材料周98165 分离群体的接种鉴定，发现周98165所含抗病基因是1对显性核基因，利用BSA法获得了与该基因连锁的8个分子标记，分别为Xbarc84、Xwmc326、Xwmc687、Xgwm299、Xbarc77、BE423472、Xwmc291 和 Xgwm108，它们间的连锁顺序为Xbarc84、Xbarc77、BE423472、Xwmc326、Xwmc687 、Xgwm299、Xwmc291、PmHNK、Xgwm108，相应的遗传距离分别为7.6cM、8.2 cM、4.9 cM、2.5 cM、3.8 cM、1.5 cM、3.8 cM和10.8 cM。其中Xwmc291和Xgwm108分别为PmHNK 两侧距离最近的标记，图距分别为3.8cM和10.3cM ，遗传距离总长度为42.6cM。根据遗传分析研究结果可以将抗病基因PmHNK定位于3BL，利用中国春的缺体-四体系验证的结果与PmHNK定位的结论相符。同时将与PmHNK连锁的标记在中国春的3BL缺失系间进行扩增，根据其结果构建了PmHNK连锁的标记的物理定位模式图，结果显示与PmHNK连锁的标记绝大部分都位于3BL-7-0.63-1.0 Bin 区。 在目前已报道的小麦白粉病抗病基因中，只有来自高大山羊草的Pm13位于3BL，在试验中用与 PmHNK 连锁的标记对 2761-5 (Pm13) 进行扩增，结果显示Pm13不能扩增出与 PmHNK 相一致的特异带型，同时利用与 Pm 13 共分离的SCAR 标记对周 98165(PmHNK) 与 2761-5进行了分子鉴定，结果表明周 98165 不含有抗白粉病基因 Pm13。另外在白粉病抗病性鉴定方面，PmHNK 与Pm13 也有明显不同，因此可以判定 PmHNK 与 Pm13是两个不同的白粉病抗病基因。 由于目前定位于3BL上的白粉病抗病基因只有 Pm13，因此可以确定周 98165 所携带 PmHNK 为一新的白粉病抗病基因。

Powdery mildew caused by Erysiphe graminis(DC)E.O.Speer f.sp.tritici,is one of the most important wheat(Triticum aestivum L)diseases in many regions of the world.In recent years,the powdery mildew harms has become worse and worse in china wheat production regions,and it has become a major disease threaten china wheat stable production and grain quality.The breeding and using of resistant cultivars is an effective,economical,and environmentally safe approach that eliminates the use of fungicides and reduces production losses due to this disease.Wild relatives of hexaploid wheat are frequently used as sources of resistance to powdery mildew and almost all of the named genes (from Pm30 to Pm43)originated outside the cultivated gene pool.Most of there genes are race-specific nation,which gain a good resistance to powdery mildew.but,when disease resistance (or other) genes are transferred from a wild relative to a crop using wide crossing and induction of recombination, the experience is that the majority of introgression events are associated with linkage drag, which is difficult to eliminate by backcrossing. That restricte greatly degree the application of wild relative gene pool in wheat breeding.Thus, where valuable genes (such as PmHNK) can be identified within bread wheat itself (such as in a landrace), their incorporation into elite germplasm is much more straightforward. In principle, the more adapted the gene donor, the greater the chance that the gene will prove useful for crop improvement. As a high- yielding and excellent comprehensive agricultural characteristics leading cultivar, The winter bread wheat cultivar Zhou98165 enjoys a high level of resistance to powdery mildew. This resistance was shown, by a series standard segregation population resistance analysis, to be conferred by a single dominant gene, given the provisional designation PmHNK. A microsatellite-based bulk segregant analysis was used to show that PmHNK is located on chromosome arm 3BL. Seven microsatellite loci (Xgwm299, Xgwm108, Xbarc77, Xbarc84, Xwmc326, Xwmc291 and Xwmc 687), and one newly-developed EST-SSR locus (BE423472) were shown to be linked to PmHNK, which is flanked by Xwmc291 (3.8cM distal) and Xgwm108 (10.3cM distal). Their linkage sequence is Xbarc84, Xbarc77,BE423472, Xwmc326, Xwmc68, Xgwm299, Xwmc291, PmHNK, Xgwm108 ,and its corresponding genetic distances(cM) are 7.6cM, 8.2 cM, 4.9 cM, 2.5 cM, 3.8 cM, 1.5 cM, 3.8 cM and 10.8 cM,which has the total size 42.6cM. As confirmed by profiling of the CS aneuploid lines, these markers all map to chromosome arm 3BL. Using a set of deletion lines involving 3BL, we can construct the physical model map of the markers,which linked with gene PmHNK and had only one amplication site in the wheat genome. What showed in this map is that most of there markers lies within chromosome bin 3BL-7-0.63-1.0. The only other major Pm gene so far located on chromosome 3B is Pm13, which was transferred to bread wheat from Ae. longissima. We have tested wheat varieties Zhou98165 and line 2761-5 with different powdery mildew isolates. While Zhou98165 is highly resistant to Bgt isolate 08B1, the line 2761-5 (carrier of Pm13) is susceptible, demonstrating that these genes are non-identical, and both linkage and segregation data showed that they cannot be allelic. The conclusion based on the resistant test that Pm13 and PmHNK must be non-allelic was confirmed by the marker analysis. Xwmc291 is closely linked to PmHNK, but is unlinked to Pm13; while the Pm13 specific marker Xutv14 developed by Cenci et al. (1999) was not present in Zhou98165.Thus PmHNK appears to be an as yet unidentified Bgt resistance gene present in bread wheat. Because Pm13 is the only named major powdery mildew resistance gene loci in 3BL,the gene PmHNK is a novel Pm gene from the bread wheat.