Abstract
Reproductive-stage drought-stress is a major production constraint in rainfed rice ecosystem. Emergence of marker-assisted breeding strategies for developing drought-tolerant rice varieties are being optimized through exploiting adaptive-traits for their increased contribution towards grain-yield under recurring-drought. Grain-yield is a complex-trait; requires knowledge of genetics and association among yield contributing component-traits. Current study was undertaken using 21 marker-assisted multi-drought-traits pyramided genotypes response for genetic variability and association of traits for grain-yield under aerobic and reproductive-stage drought conditions. Field evaluation was carried-out in two seasons and data was collected on various parameters. Path-coefficient analysis was used as a selection criterion to select yield contributing-traits and found nine phenotypic traits were having a positive direct-effect on grain-yield during both and/or at least one season under both moisture-regimes. The data from summer and Kharif seasons have been pooled within their respective moisture-regimes due to the non-significance of Levene’s test of homogeneity of variances and estimated BLUP values. ANOVA based on BLUP values revealed significant differences for moisture-conditions and also among genotypes. Phenotypic variation via. box-plots and histogram depicted mean phenotypic differences of traits under two moisture-regimes. Majority of the traits possessed high PCV, GCV with high heritability and GAM indicating higher trait expression and additive gene action lead to effectiveness of selection under drought/moisture stress. Grain-yield possessed a positive correlation with all the component-traits under consideration during both moisture-regimes. Selection of genotypes based on these component-traits were rewarding and seems to be better selection-criteria. Finally, we can end-up with superior-genotypes suitable for intermittent-drought conditions.
Highlights
Grain production is the basis of global food security and is indispensable for feeding mankind worldwide; it needs a significant increase in output in the coming decades to sustain the food and feed requirements (Mesterhazy et al 2020)
The water supply was withheld from 75 days after sowing (DAS) in RMS condition to drain out available soil moisture and reproductive stage moisture stress was imposed at 80 DAS for the period of 15 days (Fig. 1) but in the aerobic condition, need based irrigation has been given throughout crop cycle in both the seasons (Fig. 1)
The direct selection of genotypes based on component traits viz., harvest index and productive tillers can be adopted for enhancement of grain yield as they showed positive direct effect on grain yield (Khahani and Hittalmani, 2015)
Summary
Grain production is the basis of global food security and is indispensable for feeding mankind worldwide; it needs a significant increase in output in the coming decades to sustain the food and feed requirements (Mesterhazy et al 2020). About 55% of the rice area is irrigated and accounts for 75% of total rice production across the globe (Fahad et al 2019). It signifies that rice is a water intensive crop and requires 5000 litres of water per kg rice grain production (Hittalmani 2010; Jana et al 2018). To meet the growing food demands of the population, it is critical to increase the productivity levels of rice by combating abiotic and biotic stresses (Roberts and Mattoo 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
