Morpho-cultural and pathogenic variability among isolates of Rhizoctonia solani causing sheath blight of rice in Jammu.

摘要

Morpho-cultural and pathogenic variations among 15 isolates of Rhizoctonia solani obtained from sheath blight infected rice plants, 5 each from Jammu, Kathua and Udhampur areas of Jammu division, were studied during 2006-07. The isolates differed in respect of mycelial colour, hyphal width, radial growth and in size and shape, and colour of sclerotia. Despite morphological variations, the isolates showed positive hyphal fusion, and thus suggested the presence of a single anastomosis group. Subsequent reactions on maize, rice and wheat to the representative R. solani isolates led to infer that all the isolates belonged to the anastomosis group AG-1, sub-group 1A i,e. AG-1-1A. Seven variants/pathotypes were identified from different rice growing areas of Jammu on the basis of reaction types on 50 diverse rice varieties and were designated as JRS-1, JRS-2, JRS-3, JRS-4, JRS-5, JRS-6 and JRS-7. Among these the frequency of JRS-3 comprising of 4 isolates (2 from Jammu and 1 each from Kathua and Udhampur) was more than others in all three areas.