Agricultural Research Journal

The population dynamics of Rhizoctonia solani isolates from different crops in different cropping systems was studied out by population estimation after every crop grown in the sequence to establish the pathogen survival. Three cropping system adopted for the present study, included (i) potato-cotton (seedling stage)-rice, (ii) potato-mung bean-rice wheat and (iii) potato-spring maize-Basmati rice. A significant interaction was observed between R. solani isolates population and the crops grown in the three cropping systems. There was significant difference among the populations of isolates recovered after the harvest of crop and also among the isolates originating from the same host in all the three cropping patterns. The rice, maize and chilli isolates were found to have a similar trend in population build-up irrespective of the cropping system. The cotton isolate population recovery was the lowest in all the three cropping pattern. R. solani isolates from potato were found to decrease to the maximum extent when compared to the isolates from other hosts. The least population build-up after two years of rotation was recorded in the potato-spring maize-Basmati rice cropping system as the overall mean of rice isolates in this system was 44.7 cfu/g of soil, which was lower than 68.1 cfu/g of soil in the system comprising potato-mung bean rice and wheat. This indicated that the crops adopted in the third cropping pattern were not suitable for rapid multiplication of R. solani population as compared to the other cropping systems.