Identification of stable high-yielding and drought-tolerant rice (Oryza sativa L.) in the Eastern Himalayas using multi-trait stability indices

Abstract Eastern Himalayan Region (EHR), where rice is an important staple crop, developing drought stress tolerant varieties is crucial for improving yield and stability in variable climates. Genotype-by-environment (GEI) analysis is essential to understand the potential performance of the rice genotypes across environments. Present study investigated the stress responsive agro-physiological performance and stability of nine rice genotypes over two consecutive years across four distinct environments, with a focus of imparting wider climate stress resilience vis a vis augmented drought tolerance. Significant genotype-by-environment interactions were observed for 16 agro-physiological traits based on likelihood ratio test analysis. Stability and multi-trait selection were assessed using Weighted Average of Absolute Scores (WAASB) and Smith-Hazel index-based models. Genotypes, Tripura Chikan Dhan (G9), TRC-2015-10 (G5) and TRC-2015-17 (G6) were identified stable and high yielding with superior physiological traits, based on WAASB based methods. Genotypes Nagina-22 (G2) and TRC-2015-17 (G6) were identified as desirable based on the Smith-Hazel index and TRC-2015-17 (G6) outperformed all other genotypes in terms of yield and physiological traits, as determined by both WAASB based methods and Smith-Hazel method. The genotype, TRC-2015-17 (G6) exhibited the high grain yield (25.5 g/plant) along with superior physiological traits, including maximum root length (99.53 cm), root volume (132.7 cm3), and flag leaf thickness (0.22 mm). These findings emphasise the potential of Tripura Chikan Dhan (G9), TRC-2015-10 (G5) and TRC-2015-17 (G6) and ushering the scope for revalidating the same across diverse and challenging hill agro-ecologies to strengthen future breeding programme.