南充市小麦条锈病重发流行特点及其原因研究

摘要

On basis of the research result of stripe rust for 16 years since 1999, the epidemic characteristics and trend of stripe rust in the city were determined. Name-ly, the earlier the initial stage appeared, the heavier the disease would be. Further-more, stripe rust has two introduction infection peaks, of which the first peak plays a key role. ln farmlands, there are one to three epidemic peaks, and the infection area of the first peak plays the key role on the epidemic area of that year. ln ad-dition, the accumulated areas of late January was in significantly positive correlation with annual y total area, with a correlation coefficient of 0.769 2. ln recent 16 years, the frequency of severe stripe rust was as high as 81.25% which was 50% higher than that before 1995. The slight stripe rust became just in 2013, with a frequency of 6.3%, which indicated that the city has become a region hit by severe stripe rust. The internal reason is the reduction or loss of wheat variety's resistance to tripe rust for a new physiological race of rust is becoming pathogenic stronger and be the major race. Big fluctuation of temperatures in warm winter and spring, foggy and dew days slants much would be the external reason.%通过对南充市小麦条锈病1999年以来共16年的发生流行情况研究，明确了小麦条锈病在本市的重发流行特点和趋势。即病害初见期越早，发生越重；其流行特点是在本地小麦条锈菌有两次传入侵染高峰期，第1次外来菌源大范围传入对病害流行起着关键作用，在田间存在1~3个流行高峰期，其中，第1个流行高峰期发生面积对当年病害流行起着决定作用，1月下旬的累计发生面积与年总发生面积成较高正相关，其相关系数为0.7692；近16年，条锈病有13年在全市偏重至大发生，偏重至大发生频率达81.25%，比1995年以前，重发频率高50个以上百分点，轻发生只有2013年1年，仅占6.3%，说明条锈病已完全处于重发流行之态势。经对其成因探讨认为，导致本市近年小麦条锈病重发及流行的内因是品种抗条锈能力的降低或丧失，而造成小麦品种抗性丧失的直接原因是条锈菌新生理小种致病性强且已上升为主要小种，并继续保持为优势小种，暖冬和春季天气波动幅度大，雾、露日偏多直接造成了条锈病的大流行。