What does this research mean for the field?

Thirty-six stable marker-trait associations and associated candidate genes govern grain iron, zinc, and protein contents in wheat across diverse environments, providing robust targets for biofortification breeding. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to identify genomic regions associated with grain iron, zinc, and protein contents in wheat genotypes.

May 17, 2026BMC Plant Biology0 citationsOpen Access

Multi-locus GWAS to unravel the genetic architecture of grain iron, zinc and protein contents in wheat (Triticum aestivum L.) genotypes evaluated over multiple locations and years

AGAkash Gaurav RSRakhi Singh VSVikas Kumar Singh

Key Points

This study aims to identify genomic regions associated with grain iron, zinc, and protein contents in wheat genotypes.
Evaluated 283 diverse bread wheat genotypes across eight environments at three locations over three years.
Conducted multi-locus genome-wide association study (GWAS) to find stable marker trait associations (MTAs).
Analyzed phenotypic variation and genotype × environment interactions.
Identified significant phenotypic variation: GFeC (24.5-57.0 ppm), GZnC (18.0-89.9 ppm), GPC (7.38-21.64%).
Discovered 36 stable MTAs consistently across environments linked to micronutrient content.
Identified candidates genes related to metal transport and bioavailability linked to these MTAs.

Abstract

BACKGROUND: Micronutrient malnutrition, particularly deficiencies of iron, zinc, and protein in the human diet, remains a major global health challenge. Biofortification of staple crops such as wheat offers a cost-effective and sustainable approach to address the hidden hunger issue and improve nutritional quality by increasing the content of essential micronutrients. In this study, a panel of 283 diverse bread wheat genotypes was evaluated across eight environments (E1-E8) at three locations over three years to identify stable genomic regions associated with grain iron content (GFeC), grain zinc content (GZnC) and grain protein content (GPC). A multi-locus genome-wide association study (GWAS) was conducted to identify significant marker trait associations (MTAs) that were consistently detected across multiple environments, indicating their reliability for breeding. RESULTS: Significant phenotypic variation was observed across environments for GFeC (24.5-57.0 ppm), GZnC (18.0-89.9 ppm) and GPC (7.38-21.64%), indicating strong genotype × environment interactions facilitating the identification of stable genotypes with superior micronutrient content. A total of 36 stable MTAs were consistently identified across multiple environments (locations and years), indicating the presence of robust genomic regions associated with these traits. Notably, several of these MTAs were co-localized with previously reported QTLs, MTAs, meta-QTLs, and functionally characterized genes such as TaCNR2 (cell number regulator involved in Zn transport), TaIPK (phytic acid biosynthesis regulator affecting mineral bioavailability), TaABCC (metal transporter), and TaVIT (vacuolar iron transporter involved in Fe sequestration), which are known to be involved in grain micronutrient accumulation. Candidate genes (CGs) linked to these genomic regions encoded proteins such as iron-dependent dioxygenases, F-box domain superfamily proteins, ABC transporters, phosphatases, sugar transporters, and transcription factors from families such as MYB, zinc finger, and other metal-dependent regulators. CONCLUSION: Multi-environment evaluation identified highly significant and stable MTAs across environments. These MTAs, along with associated candidate genes, represented promising targets for future functional validation and deployment in marker-assisted selection (MAS) to develop biofortified wheat cultivars with stable performance across diverse environmental conditions.

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