Morphological Signs of Barley Spot Pathogens in the Conditions of the Almaty Region

摘要

The most widespread barley diseases in the southeastern region of Kazakhstan are common root rot, dark brown spots (caused by Bipolaris sorokiniana Shoem) and stripe disease ( Drechslera graminea ). This study presents the results of the morphological and cultural characteristics of fungi causing these diseases. The occurrence of the B. sorokiniana , fungi on barley leaves averaged 6.5%. They are more often was found with fungi from the genus Alternaria (35.5%). The D. graminea and Alternaria were registered in 25% of the samples. The optimal nutrient media for the cultivation of B. sorokiniana , were namely V4 medium, potato agar and Czapek's medium. The optimal temperature for the growth of colonies of B. sorokiniana were ranged from 22 to 30°C. D. graminea conidia isolated from natural substrates had a statistically significant increase in length, width and the number of septa compared to conidia grown on an artificial V4 nutrient medium. The germination energy of barley equaled 71-73% for the Astana 2000, Preriya and Symbat barley varieties, 79% for the Sever variety, 88% for the Arn variety and 96-96.5% for the Donetskiy 8 and Ilek 9 varieties.