Variability of rice sheath blight pathogen, Rhizoctonia solani from Tamil Nadu
Sathya R, Rajappan K and Ahila devi P*
Tamil Nadu Rice Research Institute, Aduthurai,Thanjavur District- 612 101
Horticultural College and Research Institute for Women, Tiruchirapalli – 620 027, India
Tamil Nadu Agricultural University, National Pulses Research centre,Vamban, Pudukottai District-622 303
*Corresponding author (Email: ahila.devi1@gmail.com)
Received: 29th August 2020; Accepted: 20th November 2020
Abstract
A survey was conducted in five different major rice growing areas of Tamil Nadu viz., Mayiladuthurai, Aduthurai, Madurai, Vellore and Thiruvarur for the occurrence of Sheath Blight (ShB) disease, which revealed that Aduthurai in Thanjavur district is the hot spot area for ShB with highest disease incidence of 64%. Among the five isolates, Rhizoctonia solani (Rs2 ) collected from Aduthurai recorded the higher severity of ShB (53.80%) followed by Thiruvarur isolate (Rs5 ) (40.23%). R. solani isolates (Rs2 ) were successfully grown on different solid media viz., potato dextrose agar, beetroot dextrose agar, carrot dextrose agar, Czapek’s dox agar and Richard’s agar. Among the nitrogen sources tested for supporting the growth of R. solani, peptone recorded the maximum mycelial growth of 8.57 cm with sclerotial production of 86.67 per plate. Of the six carbon sources tested for supporting the growth of R. solani, glucose recorded the maximum mycelial growth of 7.92. All the five isolates of R. solani were molecularly identified using ITS 1F and ITS 4 R primer pairs. The results indicated an amplicon of 600 bp in all the isolates of R. solani.