Application of Aegilops tauschii–Triticum aestivum recombinant inbred lines for grain protein content quantitative trait loci detection and wheat improvement

Abstract

Grain protein content (GPC) is an important nutritional quality trait of wheat. Aegilops tauschii Coss. is a progenitor of common wheat and has been shown to have high GPC. The objective of this study was to identify quantitative trait loci (QTL) for GPC using A. tauschii–Triticum aestivum L. recombinant lines. An advanced BC2F6 population (112 lines) containing A. tauschii segments was developed using synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × A. tauschii T093), which displayed significant phenotype variances. Two quality traits, GPC and wet gluten, and four yield-related traits, thousand kernel weight, spikelet number per plant, grain number per spike, and grain weight per spike, were evaluated. The results show that the mean GPCs of these lines were significantly higher than those of Zhoumai 18. Correlation and mapping analyses indicated that quality traits were weakly negatively correlated with yield traits. Furthermore, 16 A. tauschii-derived QTL for GPC were detected in the recombinant inbred lines, and four stable QTL that have no significant negative effects on yield and are located within the same marker interval were detected in both environments. Additionally, high-protein, high-yield lines 150228 and 150368 with stable QTL were obtained, and both can be directly utilised for fine mapping of the GPC genes and molecular marker–assisted selection to achieve synergistic improvement of wheat yield and protein content.