| 1. Symptoms and incidence of barley leaf stripe disease in several districts of Gansu province were investigated in 2008-2010.The results showed there are four types of symptoms on the barley in Gansu province.We named seedling blight, leaf stripe, no ear and white ear. The four types of barley leaf stripe disease need different environment conditions and different breeding period of barley. Temperature and air humidity were critical component to epidemic types of barley leaf stripe disease. The seed-borne fungus was the main primary infection of barley leaf stripe disease. There are two effective ways to control barley leaf stripe disease. First,to select varity which can resist barley leaf stripe disease and also come from field where barley leaf stripe disease was very light or not occuring. Second,to treat seed with fungicide.2. The chief pathogen of barley leaf stripe disease in different districts of Gansu province, according to their morphology, cultural characteristics and pathogenicity, was identified as Drechslera graminea(Rabenh.ex Schlecht.)Shoem. By studing of biological characteristics of D. graminea (Rabenh)Shoem,the results showed that 25℃,PH7 can promote the mycelial growth. PSA and PDA media were the suitable media. Sucrose and soluble starch were the suitable carbon sources. Glycine and NaNO3 were the optimum nitrogen sources.3. Genome DNA of all strains were analyzed by RAPD with 10 random primers. A total 61 RAPD bands were amplified by using 10 random primers, among which, 68.85% were found to be polymorphic. The genetic distance range of the 11 strains was 0.02-0.31. The genetic distance was closely related to gene of barley and pathogenicity of Drechslera spp..The 11 strains of Drechslera spp. were classified four groups based on cluster analysis. Group A: strains came from Yongchang Dongzhai,their pathogenicity was very weak; Group B: strains came from Ganlan Luqu and Tanzhu Huazangsi, isolated from highland barley,had strong pathogenicity; The pathogenicity of the others strains was between the Group A and Group B. The results foreshowed that the physiological differentiation of Drechslera graminea exists in Gansu province.4. In this study, we investigated the control effects of 8 kinds of fungicide against Drechslera graminea. The results showed that all of them have obvious effects on the growth of pathogen, but there are differences among them. Five fungicide namely 10%methylene bisthiocyanate, 25%propiconazole, 10%difenoconazole, 12.5% diniconazole and 3% Dividend are extremely effective to Drechslera graminea. 15% triadmefon and 80%ethylicin have less effects,however, 50% carbendazim have n't any effects to Drechslera graminea .5. There is no harmful effect on the germination percentage of barley among different dosage of different fungicides under indoor and outdoor experiments. In field fungicides test to control the Drechslera graminea by different fungicide treatment from 2009 to 2010, the results demonstrated that 0.5% methylene bisthiocyanate seed coating agent, 3% Dividend SC and 10% methylene bisthiocyanate EC could control barley leaf stripe disease effectively. Especially,0.5% methylene bisthiocyanate seed coating agent have a striking effect to control barley leaf stripe disease,also practical and cheap.6. By indoor experiments and in field testing, the results demonstrated that 9821-137,9821-118,9810-49,1109050M,9413-6-3-3,B1614,Ganpi No.4 elc barley varities could resistant against D. graminea(Rabenh.ex Schlecht.) Shoem.
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