Stem or black rust of wheat, caused by the fungus Puccinia graminis Pers. f. sp. tritici Eriks.＆E. Henn. （Pgt）, has historically caused severe losses to wheat （Triticum aestivum L.） production worldwide. In the Fujian and Guangdong provinces of China, six moderate-to-severe epidemics of wheat stem rust have occurred, which caused destructive losses of wheat between 1949 and 1966, although these were brought under control by integrated management. A rapid and reliable detection of the pathogen will contribute to the accurate forecast and seasonal control of this disease. The objective of this study was to develop a diagnostic molecular marker generated from simple sequence repeats （SSR） for the early rapid identiifcation of P. graminis. The genomic DNA of P. graminis, Puccinia striiformis, Puccinia triticina and seven other species was ampliifed by a pair of SSR primers generated by the FIASCO （fast isolation by AFLP sequences containing repeats） enrichment protocol. The primer set Pgtw （f）/Pgtw （r） generated a polymorphic pattern displaying a 330-bp DNA fragment speciifc for P. graminis whereas no DNA fragment was obtained from other non-target wheat fungal pathogens. The detection limit of the primer was 1 ng DNA in a 25-mL PCR reaction. The SSR markers of P. graminis can also be used to detect the presence of latent hyphae in Pgt-infected wheat leaves as early as 30 h post-inoculation. A rapid approach to distinguish P. graminis from similar pathogenic fungi would be anticipated in further study.
LIU Tai-guoWANG XiGAO LiLIU BoCHEN Wan-quanXIANG Wen-sheng
为探讨河南省小麦遗传背景丰富度,追溯了河南省57份小麦主栽品种的系谱信息,计算并分析了品种亲本间及品种组合间的亲缘系数（coefficient of parentage,COP）。结果表明,供试品种中只有7个品种的父母本之间有亲缘关系。1 596对组合中,757对存在亲缘关系,所有组合的COP值变异范围为0.0000~0.7500,亲缘系数总和为65.8393,平均值为0.0413。聚类分析将57份品种分为7个类群。骨干亲本豫麦2号、豫麦18号、豫麦21号、豫麦25号与57份主栽品种的共祖先度分析表明,这几个品种的利用价值很高。由此判断,供试材料的遗传背景丰富,品种组合选育优良品种还有很大潜力。骨干亲本大都是早期培育品种,今后需加强对小麦种质资源的挖掘和利用。
Mixtures composed of five wheat cultivars,Jingshuang 16,Jing 411,Jingdong 8,Lunxuan 987,and Baofeng 104,with different levels of resistance against powdery mildew were tested for their potential containment of the disease development in the field and for the influence on grain yield and the content of crude protein in the years 2007 and 2010.The plots were inoculated artificially with mixed isolates collected in the fields and propagated in the greenhouse and the disease was scored in 7 d interval during the two growing seasons.It was indicated that certain combinations,e.g.,Jingdong 8：Lunxuan 987,Jingdong 8：Baofeng 104,and Jing 411：Jingdong 8：Baofeng 104,showed positive efficacy on the mildew.The cultivar combinations tested in 2007 showed increase of grain yield,while most of the combinations tested in 2010 did not show the increase.The differences of the increases or decreases were not statistically significant except combinations Jing 411：Jingdong 8：Baofeng104,Jingshuang16：Jingdong8：Lunxuang 987 and Jingshuang 16：Jingdong 8：Lunxuan 987：Baofeng 104,which showed the decrease of the grain yield.The mixtures did not show influence on the content of crude protein in grain.More cultivar combinations need to be tested.
LI NingJIA Shao-fengWANG Xiu-naDUAN Xia-yuZHOU Yi-linWANG Zong-huaLU Guo-dong
