# Whole-genome mapping reveals QTLs linked to key agronomic traits in bi-parental populations of field cress (Lepidium campestre)

## TL;DR

This study identifies genetic regions linked to important traits in field cress, an oil crop being domesticated in the Nordic region.

## Contribution

The study maps QTLs for domestication-related traits in field cress using bi-parental populations and genome synteny with Arabidopsis.

## Key findings

- Nine QTLs linked to pod shattering were identified across eight linkage groups.
- Genes within a major QTL for pod shattering were annotated and linked to seed and plant development processes.
- Genomic resources were provided to support breeding efforts for field cress improvement.

## Abstract

Field cress, Lepidium campestre, is an oil and catch crop undergoing domestication for the Nordic region. In this study, the genetic bases of domestication-related traits of field cress are identified using three bi-parental F2 mapping populations (MPs). The MPs were phenotyped for plant height (PH), inflorescence length (IL), pod density (PD), seed yield per plant (SYPP), seed dormancy (SD), and pod shattering measured with two different parameters (PSH1 and PSH2).

The MPs were genotyped, with a targeted Genotyping-by-sequencing (GBS) method, SeqSNP, using 9,378 Single Nucleotide Polymorphisms (SNP) spanning across eight linkage groups (LGs) of field cress. There was wide phenotypic variation among the individuals for the agronomic traits measured in all MPs. A linkage map was constructed for each MP by mapping high-quality SNPs spanning 607 cM, 893 cM, and 732 cM to the eight field cress LGs, in each of the respective MPs. Quantitative trait loci (QTLs) mapping identified nine QTLs linked to PSH2, three for PH, two for SYPP, and one each for SD, IL, and PD distributed across all LGs. Taking advantage of field cress genome synteny with Arabidopsis thaliana chromosomes, annotation of the genes found within a major QTL for PSH2 found in LG5 (for MP3) revealed putative roles related to flowering, seed, and siliques development, cellulose and lignin biosynthesis, and water loss prevention.

This study identified QTLs for multiple domestication-related traits and provides genomic resources useful for applying novel breeding tools to accelerate field cress domestication and improvement.

The online version contains supplementary material available at 10.1186/s12870-025-06197-3.