Host Plant Resistance Studies on Rice Cultivars against Sheath Rot Caused by Sarocladium oryzae (Sawada) Gams and Hawksworth

Abstract

Rice sheath rot caused by the fungus Sarocladium oryzae, has become a highly destructive rice disease with a high variability in yield loss levels. Therefore, sheath rot disease can be effectively managed through crop improvement strategies viz., discovery of resistance sources from varieties, germplasm, landraces, wild genetic resources and further deploying them in breeding programmes. In this study, we evaluated 338 NSN-1 rice cultures for their resistance to sheath rot at ZARS V.C. farm Mandya during Kharif 2023with HR-12 as a susceptible check under natural and artificially inoculated conditions and disease severity was assessed using a 0-9 disease scoring scale. Our results revealed considerable variations in sheath rot resistance among the NSN-1 rice cultures. Several lines exhibited different levels of resistance, Out of 338, seven NSN-1 cultures were found immune with no disease (viz., NSN-1-4612, NSN-1-4628, NSN-1-4502, NSN-1-4304, NSN-1-5310, NSN-1-4138 and Rasi). One NSN-1-5815 line showed resistance reaction with less than one per cent disease, suggesting their potential for deployment in breeding programs aimed at developing sheath rot resistant rice varieties. These findings contribute to the ongoing efforts to enhance the resistance of rice cultivars to sheath rot, thereby ensuring the sustainability of paddy cultivation.