Genetic Variation, Heritability and Relationship between Inbred Lines Performances under Drought Stress and Irrigation Conditions in Rice

Abstract

Aims: Genetic variability and heritability for agronomic traits are key component in broadening the gene pool and as selection criteria in any rice breeding programs. In present study I estimated genetic variation and heritability of traits, examined relationships among traits and their effects on grain yield under water stressed and non-stressed conditions and distinguished cultivars that are drought tolerance, high yield potential and those that combined both high yield potential and drought tolerance. Study Design: Field experiment was arranged in a completely randomized block design. Place and Duration of Study: Study was carried in field research center Hainan of the Institute of Crop Science Chinese Academy of Agricultural Sciences China PR. from 2012-2014. Methodology: Two parents Minghui 63 and 02428 were crossed to develop 717 lines. Based on spikelet fertility ≥ 50,140 lines were selected for present study. Under drought stress field was drained at panicle initiation stage and maintained dry until maturity. In irrigation water was applied whenever necessary until maturity. At maturity, ANOVA, Dunnetts’t tests, correlation and path analysis were performed for 24 traits. Results: Correlation coefficient of trait performances between water regimes was positive and Original Research Article Joseph; AJEA, 7(5): 294-307, 2015; Article no.AJEA.2015.131 ranged between 0.3 to 0.9. Drought tolerance, yield potential and both drought tolerance and yield potential lines were distinguished. Trait genetic variation, heritability and their contribution to the final grain yield varied over genetic background, water regimes and year. Heritability in japonica type was higher under irrigation compared to drought stress. In indica background heritability was higher under drought stress in 2013, and varied in 2014. Lower values of residue effects were recorded for japonica type compared to indica background and under drought stress compared to irrigation. High filled grain number, high 1000-grain weight, moderate tiller number, short flowering time and high plant height could be selection criteria for breeding high grain yield under drought conditions. While high spikelet number coupled with high spikelet fertility, high tiller number, long panicle length, moderate plant height, and moderate flowering time are necessary for breeding high yield potential. Conclusion: These results provide a platform for dissecting genes for high yield potential, genes for drought tolerance and genes for both yield potential and high drought tolerance.