Allelic response of yield component traits to resource availability in spring wheat

Area of Science:

• Plant Genetics and Breeding
• Agricultural Science
• Crop Physiology

Background:

• Improving grain yield (GY) in spring wheat is crucial for food security.
• Understanding the genetic basis of yield components and their response to environmental resources is essential for efficient breeding.
• Quantitative trait loci (QTL) influencing yield components have been identified but their interaction with resource availability requires further investigation.

Purpose of the Study:

• To investigate the allelic response of four yield component QTL to varying resource levels.
• To determine how intraspecific plant competition and seeding density affect the performance of specific QTL alleles.
• To provide guidance for improving grain yield in both high- and low-yielding environments through targeted QTL selection.

Main Methods:

• Utilized near-isogenic lines for four previously identified QTL: QTn.mst-6B (productive tiller number), WAPO-A1 (spikelet number per spike), and QGw.mst-3B & TaGW2-A1 (kernel weight).
• Grew lines in multiple locations under controlled competition levels (border, no-border, space-planted) and seeding densities (normal, low).
• Analyzed allele effects on grain yield and yield component traits under manipulated resource availability.

Main Results:

• Allele response at QTn.mst-6B was significantly influenced by resource availability, with the QTn.mst-6B.1 allele increasing grain yield in high-resource conditions.
• Alleles at WAPO-A1 and TaGW2-A1 showed less sensitivity to resource availability.
• The gw2-A1 allele at TaGW2-A1 enhanced kernel weight, spikelet number, and protein content without negative impacts on end-use quality. Increased resource availability generally improved GY and yield components.

Conclusions:

• Genetic variation in yield component QTL, particularly QTn.mst-6B, plays a role in adapting spring wheat to varying resource environments.
• The TaGW2-A1 allele offers a valuable tool for simultaneously improving kernel weight, spikelet number, and protein content, contributing to overall grain yield.
• These findings offer practical strategies for breeders to enhance spring wheat performance in diverse agricultural settings by leveraging specific QTL alleles.