Mapping quantitative trait loci for preharvest sprouting resistance in white wheat

Area of Science:

• Plant genetics
• Agricultural science
• Crop improvement

Background:

• Preharvest sprouting (PHS) significantly impacts wheat quality and yield globally.
• Understanding the genetic basis of PHS resistance is crucial for developing resilient wheat varieties.
• North American white wheat germplasm offers a valuable, yet understudied, resource for PHS resistance.

Purpose of the Study:

• To identify quantitative trait loci (QTL) associated with PHS resistance in white wheat.
• To investigate the genetic control of PHS using a doubled haploid population.
• To explore correlations between PHS and related traits like heading date and seed dormancy.

Main Methods:

• QTL mapping was performed on a doubled haploid population (209 lines) derived from a cross between PHS-resistant (Cayuga) and PHS-susceptible (Caledonia) wheat varieties.
• Phenotypic data for PHS and related traits (heading date, plant height, seed dormancy, rate of germination) were collected across 16 environments.
• Statistical analyses were employed to detect significant PHS QTL and assess trait correlations.

Main Results:

• Fifteen PHS QTL were detected, with a major QTL, QPhs.cnl-2B.1, consistently significant across all environments, explaining 5-31% of trait variation.
• QPhs.cnl-2D.1, QPhs.cnl-3D.1, and QPhs.cnl-6D.1 were also identified with varying environmental detections.
• Heading date was negatively correlated with PHS, linked to a major heading date QTL (Qhd.cnl-2B.1) near the major PHS QTL.
• No overlap was observed between seed dormancy and major PHS QTL in greenhouse studies.

Conclusions:

• The study identified key genetic loci for PHS resistance in white wheat, particularly QPhs.cnl-2B.1.
• Findings provide a foundation for marker-assisted breeding strategies to enhance PHS resistance in wheat.
• Greenhouse assessments of seed dormancy may not accurately reflect field PHS performance.