Genetic dissection for head blast resistance in wheat using two mapping populations

Area of Science:

• Plant Pathology
• Genetics and Breeding
• Agronomy

Background:

• Wheat head blast (WB) is a destructive fungal disease threatening global wheat production.
• Host resistance is a key strategy for economical and eco-friendly WB management.
• Understanding wheat's genetic resistance loci is crucial for breeding resistant varieties.

Purpose of the Study:

• To map quantitative trait loci (QTL) associated with wheat head blast resistance.
• To identify genetic regions conferring resistance in two recombinant inbred line (RIL) populations.
• To evaluate the role of the 2NS/2AS translocation in WB resistance.

Main Methods:

• Field-based phenotyping of two RIL populations (Alondra/Milan and Caninde#2/Milan-S) across multiple locations and cropping cycles.
• Genotyping using DArTseq® technology and STS markers targeting the 2NS region.
• Quantitative trait loci (QTL) mapping to identify genomic regions associated with resistance.

Main Results:

• A major-effect QTL consistently mapped to the 2NS/2AS translocation region, explaining substantial phenotypic variation (16.7–79.4%).
• Additional minor-effect QTL (<10% phenotypic variation) were identified on chromosomes 2DL, 7AL, 7DS, 2BS, 4AL, 5AS, 5DL, and 7AS.
• The 2NS/2AS translocation was confirmed as a significant source of WB resistance.

Conclusions:

• The 2NS/2AS translocation plays a critical role in wheat head blast resistance.
• Novel QTL with potentially lower effects were identified, requiring further investigation.
• Breeding efforts should consider deploying the 2NS/2AS translocation and exploring novel QTL to reduce reliance on single resistance genes.