Evaluation of F2:3 rice population resistant to Rhizoctonia solani Kuhn inciting sheath blight disease

Abstract

Rice sheath blight caused by the soil-borne fungal pathogen Rhizoctonia solani Kuhn is an economically important disease in rice resulting in enormous yield losses worldwide. In the present investigation, a population constituting F3 lines resulted from the cross made between IC277332 (susceptible parent) and Tetep (resistant parent) were evaluated for sheath blight resistance and other agronomic traits over a season. The rice population lines were categorized into four groups viz., moderately resistant (11), moderately susceptible (63), susceptible (24), and highly susceptible (8), based on area under disease progress curve (AUDPC) values. During the study, nine moderate resistant lines showed, less AUDPC values in comparison to Tetep. Furthermore, 63 individuals (60%) exhibited moderate susceptibility with AUDPC values (677-987 per day). The principal component biplot analysis PC1 and PC2 showed 47.08% and 13.19% variation, respectively. The employment of Unweighted Pair Group Method of Arithmetic Means (UPGMA) cluster analysis led to the grouping of the 106 individuals into 2 major clusters A and B. The results suggested that none of the rice lines was resistant to sheath blight disease. However, few lines showed moderate resistance to the disease which can be exploited for the development of sheath blight-resistant cultivars.