Identification of Quantitative Trait Loci for Grain Quality Traits in a Pamyati Azieva × Paragon Bread Wheat Mapping Population Grown in Kazakhstan

Abstract

High grain quality is a key target in wheat breeding and is influenced by genetic and environmental factors. This study evaluated 94 recombinant inbred lines (RILs) from a Pamyati Azieva × Paragon (PA × P) mapping population grown in two regions in Kazakhstan to assess the genetic basis of six grain quality traits: the test weight per liter (TWL, g/L), grain protein content (GPC, %), gluten content (GC, %), gluten deformation index in flour (GDI, unit), sedimentation value in a 2% acetic acid solution (SV, mL), and grain starch content (GSC, %). A correlation analysis revealed a trade-off between protein and starch accumulation and an inverse relationship between grain quality and yield components. Additionally, GPC exhibited a negative correlation with yield per square meter (YM2), underscoring the challenge of simultaneously improving grain quality and yield. With the use of the QTL Cartographer statistical package, 71 quantitative trait loci (QTLs) were identified for the six grain quality traits, including 20 QTLs showing stability across multiple environments. Notable stable QTLs were detected for GPC on chromosomes 4A, 5B, 6A, and 7B and for GC on chromosomes 1D and 6A, highlighting their potential for marker-assisted selection (MAS). A major QTL found on chromosome 1D (QGDI-PA × P.ipbb-1D.1, LOD 19.4) showed a strong association with gluten deformation index, emphasizing its importance in improving flour quality. A survey of published studies on QTL identification in common wheat suggested the likely novelty of 12 QTLs identified for GDI (five QTLs), TWL (three QTLs), SV, and GSC (two QTLs each). These findings underscore the need for balanced breeding strategies that optimize grain composition while maintaining high productivity. With the use of SNP markers associated with the identified QTLs for grain quality traits, the MAS approach can be implemented in wheat breeding programs.

Keywords: Triticum aestivum L.; grain quality traits; mapping population; quantitative trait loci; recombinant inbred lines.

Figure 1

The distribution of the grain quality and yield-related traits of recombinant inbred lines of the PA × P population grown in two regions in the north (NKAES) and southeast (KRIAPG). Note: test weight per liter (A), grain protein content (B), grain starch content (C), gluten content (D), gluten deformation index (E), sedimentation value (F), thousand kernel weight (G), and yield per square meter (H).

Figure 2

Pearson’s correlation index for averaged data of eight traits associated with yield and grain quality in 94 RILs of PA × P population grown in the north (NKAES) (A) and southeast (KRIAPG) (B) of Kazakhstan. Note: TWL—test weight per liter (g/L); GPC—grain protein content (%); GC—gluten content (%); GDI—gluten deformation index (unit); SV—sedimentation value (mL); GSC—grain starch content (%); TKW—thousand kernel weight (g); YM2—yield per square meter (g/m²). Correlations with p < 0.05 are highlighted in blue (positive) or red (negative).

Figure 3

Position of identified quantitative trait loci (QTLs) for grain protein content (GPC), on chromosomes 5B (A) and 6A (B).

Figure 4

Genetic map of Pamyati Azieva × Paragon mapping population showing QTLs associated with grain quality traits.