Comparing wMAS, GWAS, and genomic prediction for selecting powdery mildew-resistant spring barley genotypes

Area of Science:

• Plant genetics
• Agricultural science
• Crop improvement

Background:

• Powdery mildew significantly threatens global barley production.
• Barley is a major worldwide cereal crop.
• 370 spring barley breeding lines were assessed for disease resistance.

Purpose of the Study:

• Identify genetic factors for powdery mildew resistance in barley.
• Evaluate genomic prediction models for breeding applications.
• Enhance breeding strategies for disease resistance in barley.

Main Methods:

• Genome-wide association study (GWAS) to identify quantitative trait loci (QTL).
• Calculation of genetic merit using major-effect markers.
• Performance evaluation of standard genomic prediction (GP) versus GWAS-incorporated GP models.
• Analysis of genotype selection patterns using weighted marker-assisted selection (wMAS).

Main Results:

• 21 QTL for seedling-stage powdery mildew resistance were identified, including 8 novel QTL.
• A positive correlation was found between genetic merit and BLUP (AUDPC) values.
• GWAS-incorporated GP models consistently outperformed standard GP models.
• Genomics-based methods identified resistant genotypes missed by phenotypic selection.

Conclusions:

• The GWAS-incorporated GP model is the most effective approach for breeding powdery mildew resistance in spring barley.
• This approach offers potential for efficient development of resistant barley varieties.
• Genomic methods reveal hidden genetic potential for disease resistance.