Evaluation of rice genotypes for low phosphorus stress and identification of tolerant genotypes using stress tolerance indices

Soil phosphorus (P) deficiency has emerged as one of the major limiting factors in rice production. The development and deployment of tolerant cultivars are one of the plausible approaches to combat low P-tolerance in rice. Thus, the study was carried out to identify P-stress-tolerant rice genotypes using stress tolerance indices. In the present investigation, 31 rice genotypes were evaluated under P stress and normal conditions for grain yield in two growing seasons (kharif 2017 and rabi 2017). Results from the combined analysis of variance showed a significant effect of P stress and season on grain yield among genotypes for the stress indices. Association analysis identified stress tolerance index, yield stability index, and yield index as the most appropriate indices for the selection of P-stress tolerant rice genotypes. Based on these indices, Gangavati Sona, GNV-1109, IR-30864, and FL-478 were identified as the best-performing genotypes under both optimum and P-stress conditions. Genotypes Tanu, Tellahamsa, and MTU-1001 were identified as most sensitive to P-stress. The insights from this study along with tolerant lines can be used to develop low P tolerant cultivars in rice breeding programs, which in turn helps in getting higher yields under acidic and alkaline soils to increase the farmer's income.