68个主推小麦品种的白粉病抗性分析及基因推导

Evaluation of Resistance to Powdery Mildew in 68 Chinese Major Wheat Cultivars and Postulation of Their Resistance Genes

【目的】对中国68个主推小麦品种进行抗白粉病分析和基因推导,为白粉病流行预警和防治提供依据。【方法】2011年春季在西南、西北、长江中下游、华北、黄淮和新疆麦区等12个省(自治区)采集1 094个单孢子堆白粉病菌株,并用每个菌株分别接种68个品种离体叶段进行抗感性测定;应用NTSYSpc2.10e软件对表型抗感性数据进行UPGAMA(unweighted pair group arithmetic mean analysis)聚类分析;用实验室长期收集保存的31个毒谱不同的菌株作为鉴别菌株对30个含已知抗白粉病基因材料和68个主推品种的离体叶段进行接种,比较68个品种和单基因材料对31个鉴别菌株的抗性谱,从而推导68个主推品种所含的抗白粉病基因。【结果】抗性测定结果表明,品种间抗谱存在明显差异。内麦8号、内麦9号和绵麦37抗谱宽,对各省菌群的抗性频率均大于99%;济麦22、扬麦11、扬麦12、扬麦13和轮选987等5个品种抗性频率在70%—90%;有54个品种的抗性频率小于40%,占供试品种总数的79.4%,表明大部分主推品种的抗性已被克服。某品种对该品种推广种植区域菌群的抗性频率低于对其它非种植区域菌群的抗性频率。聚类分析可将68个品种分成4大类,第I类包括6个品种,其中5个品种抗性频率在40%—70%;第II类包括7个品种,抗性频率均大于70%;第III类包括54个品种,抗性频率均小于40%;第IV类包括1个品种,抗性频率为46.1%;聚类显示来自于同一省的品种、抗性频率相近的品种具有相似或相近的抗性遗传背景。基因推导表明,内麦8号、内麦9号含有Pm21,偃展4110、新麦208和扬麦11均含有Pm4b;济麦22含有Pm2+ta;其余品种含有其它未知抗白粉病因子。【结论】当前中国主推小麦品种中近80%的品种对全国白粉病菌群的抗性频率不高,特别是就单个品种而言,对该品种种植区的白粉菌群抗性频率更低,存在小麦白粉病在条件适合时暴发流行的风险,必须加强病害预警。同省品种的抗性频率聚类大多聚到同一组,说明同省品种的抗源异质性不高,中国小麦白粉病育种应该引进更丰富抗源。

【Objective】 Resistance of 68 major wheat cultivars,each of which is planted at least over 70 thousand hectares yearly in China,to powdery mildew was analyzed based on resistance frequencies to mildew population from different provinces/ autonomous regions and whole China in order to evaluate the risks of mildew epidemics.Their resistance genes were also postulated.【Method】1 094 wheat single colony powdery mildew isolates were collected from 12 provinces（autonomous region） which grow wheat in China in the spring of 2011.Resistance frequencies of 68 cultivars were estimated by the mean of inoculating detached leaves segments of each cultivar with 1 094 isolates,respectively.Cluster analysis was carried out with UPGAMA（unweighted pair group arithmetic mean analysis） model of the software NTSYSpc2.10e based on the phenotypic resistance data.Resistance genes of the 68 cultivars were postulated by comparing resistance spectra of the cultivars to 31 differential isolates with those of materials possessing known resistance genes to the isolates.【Result】 The resistance spectrum of each cultivar differed significantly from that of others.Resistance frequencies of Neimai8,Neimai9 and Mianmai37 were higher than 99%,while those of Jimai22,Yangmai11,Yangmai12,Yangmai13 and Lunxuan987 were between 70% and 90%.Among the 68 cultivars,54 cultivars counting for 79.4%,had resistance frequencies lower than 40%,suggesting the resistance of these cultivars had been overcome.The resistance frequency of a cultivar to mildew population from the region where the cultivar was grown was lower than that to the mildew population from the region where the cultivar was not grown.Cluster analysis indicated 68 cultivars could be classified into four groups.Group one included 6 cultivars and out of them,resistance frequencies of 5 cultivars to all isolates were between 40% and 70%.Group two included 7 cultivars with resistance frequencies higher than 70%.Group three composed of 54 cultivars with resistance frequencies lower than 40%.The fourth group had only one cultivar with resistance frequency of 46.1%.The cultivars came from the same province and the cultivars with the similar resistance frequency had been clustered to the same group.It showed that they may have a similar resistance genetic background.Results of Pm postulation showed that Neimai8 and Neimai9 contains Pm21,Yanzhan4110,Xinmai208 and Yangmai11 possess Pm4b,Jimai22 possesses Pm2＋ta,while the rest cultivars contain other unknown resistance factor（s） which could not be postulated.【Conclusion】Nearly 80% of the cultivars wildly grown in China have a lower resistance frequency to wheat powdery mildew population.Referring to a cultivar,it was vulnerable to mildew population from the area where the cultivar is grown.There would be a risk of wheat powdery mildew epidemic if weather and other conditions favor for mildew epidemic.Many cultivars from the same region were clustered into the same group,it indicated that the resistance heterogeneity is lower in wheat grown in the region.