山西冬麦区小麦全蚀病发生规律及不同品种的耐病性鉴定

全蚀病在山西省冬麦区于小麦１～２分蘖期开始发病，灌浆期病势达到高峰，小麦一生均受到该病的胁迫。白穗出现时间的早晚与小麦千粒重和穗粒数之间呈高度正相关，相关系数分别为ｒ＝０．９９５９和ｒ＝０．８４５６，即白穗出现时间愈早，对二者的影响愈大。在小麦的适宜播种期内，随着播期的推迟，病害有明显减轻的趋势。通过模糊聚类分析，将供试品种分为４个类型，即耐病高产型、耐病中产型、感病中产型和感病低产型。

The Fluctuation Law of Wheat Take-all and Identify of Varietal Tolerance to Tall-all in the Producting Area of Winter Wheat,Shanxi

During 1991 and 1992,this observation was conducted in Yuncheng district, Shanxi. The results showed that the initial stage of wheat tall-all (Gaeumannomyces graminis Var. Tritici)was at 1 or 2 tiller of wheat, and the peak of invasion occured at the filling stage. The all- life of wheat was stressed by the disease. There was a positive correlation between the time of occuring white head and thousand kernel weight,and between the time of occuring white head and kernel number per spike. The correlation coefficients were 0. 9960 and 0. 8456, respectively,i. e.,the earlier the white head appears,the severer the loss of yield components due to the disease is. With the time of sowing delaying,the severity of take-all decreases apparently during the suitable time of sowing for wheat. By the analysis of the fuzzy clustering method,the varieties of wheat tested were divided into four types,i. e., the tolerance with high yield; the tolerance with mean yield; the susceptibility with mean yield; and the susceptibility with poor yield.