Root Traits Enhancing Rice Grain Yield under Alternate Wetting and Drying Condition.

Area of Science:

• Agricultural Science
• Plant Breeding
• Agronomy

Background:

• Reducing water usage in agriculture is critical for sustainability and food security.
• Alternate wetting and drying (AWD) is a water-saving irrigation technique for rice cultivation.
• Optimizing rice genotypes for AWD can enhance water use efficiency without compromising yield.

Purpose of the Study:

• To identify specific root traits that improve rice grain yield under AWD conditions.
• To select stable and high-yielding rice genotypes suitable for AWD across diverse environments.
• To understand the relationship between root architecture and yield performance under water-saving irrigation.

Main Methods:

• Conducted 23 field experiments across five countries (Philippines, India, Bangladesh, Nepal, Cambodia) in 2015-2016.
• Evaluated advanced breeding lines, popular varieties, and drought-tolerant lines under AWD.
• Utilized Finlay-Wilkinson regression and multidimensional preference analysis to identify stable genotypes and key root traits.

Main Results:

• Achieved water savings of 5.7-23.4% with no significant yield penalty.
• Identified eight stable genotypes with mean grain yields exceeding 5.0 t/ha.
• Found strong associations between nodal root number, root dry weight, and grain yield, particularly at 22-30 days after transplanting (DAT).
• Genotype IR14L253 showed superior root traits and a 1.0 t/ha yield advantage over IR64 under AWD.

Conclusions:

• Specific root architectural traits, like increased nodal root number and dry weight at shallow depths (10-20 cm), enhance yield stability under AWD.
• Breeding programs can leverage these root traits to develop superior rice varieties for water-saving cultivation.
• Adoption of AWD irrigation and improved rice varieties like IR14L253 can significantly contribute to water conservation and food security.