# A novel, major, and validated QTL for grain zinc concentration independent of yield traits in tetraploid wheat

## TL;DR

This study identifies a new genetic region in tetraploid wheat that increases grain zinc without affecting yield traits, offering a tool for improving wheat nutrition.

## Contribution

A novel and stable QTL for grain zinc concentration in tetraploid wheat, independent of yield traits, is identified and validated.

## Key findings

- A major QTL, QGrZnc.sau-AM-4A, was detected across all environments and explained 12.31%–30.50% of phenotypic variance.
- The QTL had no significant impact on key agronomic traits, indicating no dilution effects.
- A KASP marker linked to the QTL was developed and validated for use in marker-assisted selection.

## Abstract

Zinc deficiency is a critical global health issue, with declining grain zinc concentration (GrZnc) over time. To address this, it is essential to explore and utilize genetic resources from wild relatives to enhance GrZnc in cultivated bread wheat (Triticum aestivum L.). This study aimed to identify quantitative trait loci (QTL) for GrZnc using a recombinant inbred line population (AM population), derived from a cross between the Sichuan‐endemic tetraploid wheat Ailanmai and wild emmer accession LM001. A linkage map was constructed based on the wheat 55K single‐nucleotide polymorphism array, and phenotypic data were collected from five different environments. Four QTL for GrZnc were identified, spanning three chromosomal regions. Notably, a novel and stable QTL, QGrZnc.sau‐AM‐4A, was detected in all environments and the best linear unbiased prediction dataset. This QTL, with LOD values ranging from 2.72 to 9.31, explained 12.31%–30.50% of the phenotypic variance and was mapped to chromosome arm 4AS (54.43–60.02 Mbp). Interestingly, this QTL had no significant effect on key agronomic traits such as spike length, 1000‐kernel weight, kernel number per spikelet, spikelet number per spike, spike density, and plant height, indicating no dilution effects. A kompetitive allele‐specific PCR (KASP) marker, KASP‐AX‐108829087, closely linked to this major QTL, was developed and validated in two different genetic populations. A candidate gene (TRIDC4AG008520) related to zinc absorption and transport was identified within the QGrZnc.sau‐AM‐4A interval. These findings provide insight into the genetic basis of GrZnc and establish a foundation for further fine mapping and map‐based cloning of this locus.

This study identifies quantitative trait loci (QTL) for grain zinc concentration in tetraploid wheat.QTL were identified using a recombinant inbred line population and a wheat 55K single‐nucleotide polymorphism array‐based constructed genetic map.The genetic effects of the major and stable QTL for grain zinc concentration was validated in genetic backgrounds.Tightly linked kompetitive allele‐specific PCR (KASP) marker (KASP‐AX‐108829087) can be further used in molecular marker‐assisted selection.

This study identifies quantitative trait loci (QTL) for grain zinc concentration in tetraploid wheat.

QTL were identified using a recombinant inbred line population and a wheat 55K single‐nucleotide polymorphism array‐based constructed genetic map.

The genetic effects of the major and stable QTL for grain zinc concentration was validated in genetic backgrounds.

Tightly linked kompetitive allele‐specific PCR (KASP) marker (KASP‐AX‐108829087) can be further used in molecular marker‐assisted selection.