大麦条纹病的初侵染和再侵染的研究

甘肃河西地区大麦条纹病的初侵染和再侵染的研究结果表明，种子带菌是该地区主要的初侵染源，病残组织也可成为初侵染源。室内、田间接种均证明了条纹病有再侵染现象，大田发病率２３．５０％～３７．８０％，产量损失８％以下，潜育期４～７ｄ。再侵染成功与否及发病率高低与空间生态位有关；大田中心病株以点传播，有重叠侵染现象；六月份多雨及夜间结露有利于进行再侵染；再侵染的侵染率高低与中心病株的多寡成正相关。经成偶法检验符合中心式传播，侵染梯度模型为：ｌｎｘ＿ｉ＝－０．３１４４－０．９６１５ｌｎｄ＿ｉ，即Ｘ＝０．７３０２／ｄ￣（０．９６１５）＿ｉ。

On the Primary and Secondary Infection of Stripe Disease of Barley Caused by Drechslera graminea

The results of primary and secondary infection of stripe disease of barley inHexi,Gansu showed that the seed-borne fungus was the main cause of pereration of thepathogen from season to season. Some infection occurred from the mycelium perpetuating inthe soil on stubble of the previous year’s diseased crop.The test of seed-borne inoculation tothe principal cultural varieties in the field was made by isolation,tube culture with nutrientsolution, flower-post culture. The secondary infection resulted in local infectiion,centralspread, loss of yields below 8%and the inoculation period for 4～7 days,the incidence of dis-ease in the field was 23.5%～37.8%, and the reinfection gradient model was X=0.7302/d￣(0.9615)_i。