Wheat traits and the associated loci conferring radiation use efficiency

Area of Science:

• Agricultural Science
• Plant Breeding
• Crop Physiology

Background:

• Wheat yield potential is increasingly limited by the harvest index, necessitating improvements in radiation use efficiency (RUE).
• Enhancing RUE through crop breeding is crucial for further increasing wheat grain yield.

Purpose of the Study:

• To evaluate variations in phenological, physiological, plant architectural, and yield-related traits across 209 Chinese wheat cultivars.
• To identify traits contributing to RUE and pinpoint limiting factors for wheat yield potential.
• To identify superior wheat cultivars for breeding programs aimed at improving yield and RUE.

Main Methods:

• Conducted field experiments over two growing seasons (2018-2020) with 209 wheat cultivars.
• Assessed phenological, physiological, plant architectural, and yield-related traits.
• Analyzed genetic gains in grain yield and RUE, and correlated net photosynthetic rates with RUE and yield.

Main Results:

• Average annual genetic gain in grain yield was 0.60%, primarily driven by gains in RUE (r=0.85, P<0.01).
• Net photosynthetic rates showed a strong positive correlation with grain RUE and grain yield, indicating source limitations.
• Identified 34 cultivars with high RUE and other critical traits suitable for breeding.

Conclusions:

• Source capacity, indicated by net photosynthetic rates, is a limiting factor for future wheat yield gains.
• Identified specific wheat traits and associated genetic loci that confer high RUE.
• Findings facilitate marker-assisted breeding for enhanced wheat RUE and yield potential.