Abstract
Drought stress is a major constraint for rice (Oryza sativa L.) production and yield stability in rainfed ecosystems. Identifying genomic regions (QTLs) contributing in drought resistance will help to develop rice cultivars suitable for water-limiting environments through marker-assisted breeding. QTLs linked to physio-morphological and plant production traits under drought stress in the field were mapped by evaluating 177 F6 recombinant inbred (RI) lines of Bala × Azucena under rainfed conditions in the target environment (TE). The rice lines were subjected to severe drought stress during reproductive phase due to a natural rainfall failure event. The RI lines showed significant variation in physio-morphological and plant production traits under stress. A total of 24 QTLs were identified for various traits under stress, which individually explained 4.6 to 22.3% phenotypic variation. Composite interval mapping detected three markers viz., RM3894, RG409 and G1073 on chromosomes 3 and 8 linked to grain yield under drought stress in TE, respectively explaining 22..3, 17.1 and 10.9% of phenotypic variation. QTLs for leaf drying, days to 50% flowering and number of productive tillers under drought stress co-located at certain of these regions. Further, QTLs for several root traits overlapped with QTLs for grain yield under stress in these RI lines, indicating the pleiotropic effects of root trait QTLs on rice performance under stress. Correlation coefficients between potential root traits determined in another study and plant production under stress in this study were not significant in these RI lines. Consistent QTLs for drought resistance traits and yield under drought stress in TE were detected and might be useful for rainfed rice improvement.
Highlights
Rice[1] (Oryza sativa), one of the important food crops, is grown on 154 million hectares world-wide in a wide range of environments[1]
There was a continuous rain free period of 58 days starting from 60 days after emergence (DAE) of seedlings up to maturity and the recombinant inbred (RI) lines were subjected to severe water stress during the reproductive phase
Similar genotypic variation in physio-morphological and plant production traits under drought stress was reported earlier in these RI lines[26] and several other rice lines from experiments conducted in managed stress environments (MSE)[23,24,35,36,37,38,39]
Summary
Rice[1] (Oryza sativa), one of the important food crops, is grown on 154 million hectares world-wide in a wide range of environments[1]. About 45% of the world’s rice is cultivated in rainfed ecosystems[2] These areas often experience severe water deficits due to low and uneven rainfall distribution patterns and yields are largely reduced by drought. Yield improvements in water-limited environments can be achieved by selecting for secondary traits contributing to drought resistance in breeding programs. The effectiveness of selection for secondary traits to improve yield under water limiting conditions has been demonstrated in maize[6], wheat[7] and sorghum[8]. There is a need to determine whether the QTLs linked to drought resistance traits impact yield under stress in field conditions. Chandra Babu, Centre for Plant Molecular Biology, TNAU, Coimbatore-641003, India
Sign-in/Register to view highlights & summary 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 callMore From: American Journal of Biochemistry and Biotechnology
Disclaimer: 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.
