Water Stress induced Trait Association Studies on Yield and Drought Selection Indices in Rice (Oryza sativa L.)

Author: S. Anand, V.G. Jayalekshmy, S. Bhaskar Reddy, M.O. Ankitha and Akhila Ashokan

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Abstract

Drought stress is considered the most serious of all biotic and abiotic stresses affecting rice, resulting in severe yield loss. Detailed understanding regarding the contribution of traits towards yield and identification of the most effective selection indices under diverse soil moisture levels can equip plant breeders in the selection of climate adaptive genotypes. Rice being a crop that is affected severely by water stress, defining specific combinations of drought selection indices for the selection of genotypes that can perform better under water-stressed and non-stressed conditions is mandatory to ensure stable yield. The present study elucidates the relationships between grain yield of contrasting rice genotypes with various drought selection indices for the selection of stress-tolerant and high-yielding genotypes under diverse regimes of water availability. Nine drought selection indices and three contrasting genotypes were used in the study. A comparative evaluation of the grain yield of the genotypes was done under non-stress and drought-stress environments. Drought selection indices were worked out, followed by correlation studies and principal component analysis (PCA). Drought selection indices namely MP, GMP, HM, STI, and YI were identified to be the suitable indicators with significant positive correlations that can be used in selection for high grain yield under both water-stressed and non-stressed conditions. In PCA analysis, two principal components i.e., PC1 and PC2 accounted for 58.98% and 41.02% of the total variation in grain yield. Results from the biplot based on PCA were in line with the interpretations of correlation analysis. Genotypes with higher YSI and RSI values can be utilized to achieve better stability in yield across contrasting soil water conditions in rice.

Keywords

Water stress, Correlation, PCA, Biplot, Drought selection indices, Drought, Rice

Conclusion

Drought is an important abiotic stress which affects all plant growth processes and yields in rice. The present study on drought section indices helps in deciphering a combinatorial approach in the selection of superior genotypes under drought and well-irrigated environments. Character association studies conducted in the present study revealed that out of the nine drought selection indices, high measures of MP, GMP, HM, STI, and YI values for a genotype are indicative of higher yield and drought resistance. Rice genotypes with higher YSI and RSI values show better stability in yield across contrasting soil water regimes. Multivariate analytical methods prove their accuracy in handling and comparison of yield (under stresses and non-stress) and stress selection indices of diverse rice genotypes and provide a holistic selection approach in rice. Similar studies focusing on superior performance under diverse conditions can provide theoretical support and a material basis for future variety screening and selection in rice breeding.

References

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How to cite this article

S. Anand, V.G. Jayalekshmy, S. Bhaskar Reddy, M.O. Ankitha and Akhila Ashokan (2023). Water Stress induced Trait Association Studies on Yield and Drought Selection Indices in Rice (Oryza sativa L.). Biological Forum – An International Journal, 15(4): 324-329.