QTL Mapping for Important Agronomic Traits Using a Wheat55K SNP Array-Based Genetic Map in Tetraploid Wheat

Area of Science:

• Plant genetics and breeding
• Agricultural science
• Genomics

Background:

• Wheat yield is significantly influenced by plant height, heading date, spike morphology, and kernel characteristics.
• Understanding the genetic control of these traits is crucial for improving wheat varieties.
• Tetraploid wheat possesses a complex genome, making genetic analysis challenging.

Purpose of the Study:

• To construct a genetic linkage map for tetraploid wheat.
• To identify quantitative trait loci (QTLs) associated with important agronomic traits.
• To analyze QTL-environment interactions and epistatic effects for trait improvement.

Main Methods:

• Genotyping of a 165-line recombinant inbred line population using the wheat55K SNP array.
• Construction of a genetic linkage map covering 14 chromosomes of tetraploid wheat.
• QTL mapping for 12 agronomic traits across multiple environments, including analysis of QTL-by-environment interactions and epistasis.

Main Results:

• A genetic map of 6244.51 cM was constructed.
• 52 major or stable QTLs were identified for traits including plant height (PH), heading date (HD), awn color (AC), and spike-branching (SB).
• Novel loci for PH, SB, and kernel length-width ratio (LWR) were detected, explaining significant phenotypic variation (2.40-66.27%).
• Candidate genes were predicted for four stable QTLs using reference genome annotations.
• 31 QTL clusters and 44 segregation distortion regions were identified, containing many major/stable QTLs.

Conclusions:

• The identified QTLs offer potential for marker-assisted selection in tetraploid wheat breeding.
• This study expands the genetic understanding of key agronomic traits in wheat.
• The findings contribute to broadening the genetic basis for improving traits like PH, HD, AC, and SB in wheat.