High resolution mapping of agro-morphological and grain traits in bread wheat using SNP-based QTL analysis

Area of Science:

• Agricultural Science
• Genetics
• Plant Breeding

Background:

• Wheat (Triticum aestivum L.) is a globally significant staple crop, necessitating continuous improvement in yield and grain quality.
• Understanding the genetic basis of key agronomic traits is crucial for effective breeding strategies.

Purpose of the Study:

• To identify quantitative trait loci (QTLs) associated with important agronomic traits in a wheat recombinant inbred line (RIL) population.
• To explore potential genomic regions for marker-assisted selection to enhance wheat yield and grain quality.

Main Methods:

• Evaluation of 188 RILs across three consecutive growing seasons for traits including plant height, spike length, thousand kernel weight, and kernel dimensions.
• High-density genotyping using 910 SSR markers and a 35K SNP array.
• QTL analysis to map genetic loci controlling phenotypic variation.

Main Results:

• Significant phenotypic variability and quantitative inheritance were observed for all evaluated traits.
• Twenty-eight QTLs were identified across 16 chromosomes, with specific loci for plant height, spike length, spikelets per spike, thousand kernel weight, kernel length, kernel width, and kernel thickness.
• A consistent QTL (QTkw.iari_4B) associated with thousand kernel weight co-localized with QTLs for plant height, kernel length, and kernel thickness, suggesting a pleiotropic or tightly linked region.

Conclusions:

• The identified QTLs, particularly QTkw.iari_4B, represent valuable genetic resources for wheat breeding programs.
• These findings provide a foundation for marker-assisted selection strategies aimed at improving yield and grain quality traits in wheat.
• In silico analysis identified candidate genes within QTL regions, offering insights into the genetic regulation of these traits.