甘肃小麦条锈菌耐温性菌系的界定及其对条锈病流行的作用

Longnan region of Gansu province is labile region and new race cradle, and is one of the largest and most important over summering areas of Puccinia striiformis f. sp. Tritici (PST) in China.The survival and growing temperature of PST has to rise with the climatic warming. Effect of climate warming for the temperature resistance stains emerge. A large number of the temperature resistance stains has amplified the growing scope about the wheat strip rust. We have studied temperature resistance and races of PST. And we have gotten 41 temperature resistance stains. The study is to standardize the temperature resistance stains by testing temperature-specific adaption; Counting up the occurrence frequency and distribution region in GanSu province; To analysis genetic similarity of the temperature resistance stains from different regions by SSR; To classify the wheat-growing regions for the pathogen oversummering in China by using the Geographic Information System(GIS) combine with meteorological data analysis and disease investigation. These results can provide theoretical foundation for durative control the wheat strip rust.

甘肃陇南地区是中国小麦条锈菌主要的越夏"易变区"和新小种的发源地，是中国小麦条锈菌最主要和最大的越夏区。气候变暖迫使条锈菌生存生长温度增高，导致大量耐温性菌系出现，扩大了条锈病的发生与危害范围。项目组前期对甘肃近年来的流行生理小种及致病性类群进行了温度与寄生适合度研究，筛选出41株耐高温性菌株。本研究拟对已选定的高温性菌株进行病害抑制温度中值测定，明确耐温性菌系的界定温度，进而统计耐温性菌系在甘肃的出现频率与分布区域；通过小种鉴定，划分其致病类群；通过SSR技术，分析不同区域耐温性菌系的遗传相似度；利用GIS软件构建甘肃小麦条锈菌越夏区气候区划图，结合气象资料分析和病情调查，超前预测小麦条锈病的发生趋势。本研究为小麦条锈病的有效防治提供理论依据。

甘肃陇南地区是中国小麦条锈菌的“菌源易变区”和新小种的“策源地”，是中国条锈菌变异的关键地带。为明确气候升高与条锈菌变异的关系，进行以下研究：通过生理小种监测，发现 G22 致病类群上升为第一大致病类群，占61%，CYR34上升为流行小种，占 34% 左右。通过病害调查，发现甘肃中部地区条锈病近些年发病较重，但甘肃地区条锈病整体发病低于以前。通过对条锈菌进行高温适应性，发现小麦条锈菌对高温的耐适性逐年提高；将耐高温菌的潜育期比原始的温敏性菌系进行比较，发现耐高温菌的潜育期比温敏性菌系短，表明耐高温菌系的致病力强于原始的温敏性菌系；通过对耐高温菌系与原始的温敏性菌系在高温胁迫下进行萌发率、潜育期及病斑扩展面积的比较，发现中国小麦条锈菌耐高温菌系的侵袭力强于原始的温敏性菌系。将条锈菌的耐高温性与毒性进行比较，发现生理小种的耐高温性表现为CYR32 > CYR33 > SU11-4。将耐高温性与海拔进行比较，发现低海拔的地区条锈菌的成活率高于高海拔地区。