Virulence diversity in Rhizoctonia solani isolates of different maize growing ecosystems of India

摘要

Fifty eight Rhizoctonia solani isolates collected from maize (43), rice (12), moong (2) and pigeon pea (1) were inoculated on to 35 days old susceptible maize cv. Vivek QPM-9 by placing two to three barley grain inoculum between stalk and sheath at second or third inter-node level.The virulence diversity among the isolates revealed that all the isolates could cause infection on maize susceptible cultivar irrespective of their hosts of origin. The time taken for R. solani isolates to express symptomson maize crop varied from 1.0 to 3.4 days. The percent disease index (PDI) ranged from 56.0 to 90.0%. The virulence index varied from 16.5 to 90.0. The length of infected area recorded in different R. solani isolates ranged from 50.2 to 85.6 cm. The relative length of infected area produced by different isolates varied from 26.7 to 45.5%. Among all isolates, two maize isolates M25 and M16 of R. solani 1. sp. sasakii were superior in all above mentioned parameters.