Virulence Spectrum among Rhizoctonia solani f. sp. sasakii Isolates from Multi-Geographical Locations of India

Abstract

Rhizoctonia solani f. sp. sasakii (RSS) is a highly devastating soil-borne fungal pathogen inciting banded leaf and sheath blight (BLSB) disease in maize. In India, annually one percent of the total maize yield is reduced by BLSB. Due to continuous occurrence and wide spread of disease, the present experiment was conducted to assess the pathogenic variability among different isolates obtained from multi-geographical locations of India. Pathogenic behaviour of each isolates was predicted through the comparable study of their incubation period, average disease score and disease intensity on the three maize hybrids (Normal maize- HM 8, QPM maize- QPM 9 and sweet corn- HSC I). The incubation period of all the R. solani isolates ranged from 3 to 7 days with average disease score ranged from 2.1 to 7.1depending upon the host and isolate interaction after artificial inoculation. Disease intensity of all the RSS isolates on maize hybrids varied from 8.1 to 52.1% while isolates RSS 29 (New Delhi) and RSS 1 (Karnal) were found highly virulent, in comparison to other forty nine RSS isolates. As these isolates were highly virulent on maize hybrids with average disease score ranged from 6.2 to 7.1, whereas the isolates RS 30 (Dholi) and RS 31 (Dhaula Kuan) were recorded as least virulent, showed resistant disease reaction with average disease score ranged from 1.5 to 2.4.

Genetic diversity and resistance assessment among maize genotypes against banded leaf and sheath blight (caused by Rhizoctonia solani f. sp. sasakii) utilizing SSR markers

“…A total of 14 anastomosis groups namely AG1‐ AG13 and AG BI have been reported in Rhizoctonia (Carling et al, 2002; Kumar, Kaur, & Hunjan, 2021). In India, the occurrence of BLSB has been attributed to two species of Rhizoctonia namely R. solani and R. oryzae‐sativae (Kumar, Kaur, & Hunjan, 2021), which consist primarily of anastomosis group AG1‐IA in maize and rice (Kumar, Kaur, & Hunjan, 2021; Kumar, Mehra, Kumari, Sarita, & Yadav, 2022; Singh et al, 2018). Rhizoctonia solani attacks the basal portion (lower leaf and sheath) of maize plants and induces small water‐soaked lesion.…”