Integration of HMW-GS and retrotransposon marker LTR14 for selection of wheat genotypes combining baking quality and resistance to take-all disease

Abstract

Abstract

BACKGROUND: Improving bread wheat genotypes that combine durable resistance to take-all disease with high yield and favorable baking quality is an important objective in wheat breeding programs. RESULTS: In this study, 97 bread wheat genotypes were selected from an initial collection of 1000 accessions based on previous phenotypic evaluations to ensure broad agronomic and quality-related diversity. In addition, three control cultivars (Roshan, Kavir, and Sardari) were included in the evaluation. These genotypes and control cultivars were evaluated for high molecular weight glutenin subunit (HMW-GS) composition, agronomic traits, disease severity (DS), and baking quality (BQ). SDS-PAGE analysis identified 11 HMW-GS, among which 5 + 10 (Glu-D1), 2* (Glu-A1), and 17 + 18 (Glu-B1) were associated with superior baking quality. The retrotransposon-based marker LTR14, previously associated with reduced disease severity, was excised, purified, and sequenced (NCBI GenBank accession number PX660489.1). Sequence analysis revealed partial similarity to γ-gliadin- and storage protein activator-related sequences. Correlation analysis showed a significant negative association between LTR14 and DS (r = -0.405, p < 0.05) and a positive association with lignin content (r = 0.310, p < 0.05). Heatmap clustering divided the genotypes into six groups, among which clusters 3 and 6 exhibited favorable combinations of low disease severity, high baking quality, desirable yield components, and the presence of LTR14 and favorable HMW-GS alleles. Principal component analysis explained 76.2% of the total variation, with PC2 positively associated with baking quality and grain yield traits and negatively associated with disease severity. Using the TOPSIS-based similarity index to the best conditions (SIB ≥ 0.75), nine genotypes were identified as promising candidates with favorable combinations of disease resistance, baking quality, and agronomic performance. CONCLUSIONS: The results provide preliminary sequence-based characterization of the LTR14 retrotransposon-derived marker associated with reduced disease severity and suggest possible relationships with storage protein-related genomic regions. The integrative multi-trait framework applied in this study provides a preliminary strategy for identifying promising wheat genotypes for marker-assisted breeding programs targeting disease resistance, grain quality, and agronomic performance. However, it is important to emphasize that the study was conducted under a single environmental condition and sequence characterization was based on only one resistant genotype. Therefore, the observed associations must be considered preliminary, and substantial further multi-environment validation and broader sequencing analyses are essential to confirm the stability and broader applicability of these findings before any practical recommendations can be made.