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众所周知,在一定范围内感病品种面积的多少,则是预测病情趋势的主要依据之一。从我县十六年来,对感病品种面积所占比例与病情轻重的相关统计分析,二者呈极显著相关。又从我县历史上分析,一个主栽品种示范推广到逐步淘汰一般需5—6年。这实际上就是一个品种从育成时的相对比较抗病,最后逐渐丧失抗性的过程,也就是说,一个新品种的示范推广,到了一定年限就潜伏着抗性丧失的开始,也就孕育着病害流行的可能。这样,每当感病品种较大面积存在时,遇到有利于发病的天气条件,病害势必流行。从育种工作趋向看,今后品种更换的周期将比以前缩短,解放前和初期农家品种为主,
As we all know, in a certain range of the number of susceptible species area, it is one of the main basis for predicting the trend of the disease. From the county sixteen years, the proportion of susceptible species area and the severity of the statistical analysis, the two were significantly correlated. Again from the history of our county, a variety of cultivars to promote the general phase-out to be 5-6 years. This is actually a breed from a relatively more resistant to disease resistance, and finally gradually lose the resistance of the process, that is, a new breed of demonstration and promotion, to a certain age lurking the beginning of the resistance loss, it pregnant Disease epidemic may be. In this way, whenever a large area of susceptible species exists, weather conditions conducive to the onset of the disease are bound to prevail. Looking from the trend of breeding work, the cycle of variety replacement will be shortened in the future, mainly before and after liberation,