Harnessing wild relatives for improved salt tolerance in wheat

Walker, Jack

Harnessing wild relatives for improved salt tolerance in wheat

Publication Date

July 30, 2026

Creator

Walker, Jack

University of Nottingham

Abstract

In this study, a high-throughput hydroponic screening system was established to evaluate salt tolerance in wheat, its wild relatives, and wheat–wild relative introgression lines during vegetative growth. Plants were subjected to increasing salt stress for approximately three weeks, after which shoot dry weight, tiller number, SPAD values, and leaf ion content were assessed. Early seedling responses were also evaluated using morphological root and shoot traits. Under high salt stress, Thinopyrum species and select introgression lines outperformed wheat, maintaining shoot growth and tillering while restricting sodium accumulation in leaves. Notably, Th. ponticum and Th. elongatum, as well as Th. bessarabicum amphiploids, displayed strong tolerance. Introgressions from linkage groups 1 and 6 of Th. elongatum and chromosome 5J of Th. Bessarabicum were associated with enhanced K/Na ratios, reduced sodium accumulation, and sustained shoot and root growth. All Thinopyrum species accumulated more sodium under control conditions, suggesting sodium may serve as an osmoticum for maintaining cell turgor. To further exploit this genetic variation, a wheat × Th. ponticum breeding programme was initiated. Introgressions were characterised using KASP genotyping, GISH, and low-coverage skim sequencing. Although stable homozygous introgressions were not recovered, this work establishes a foundation for future breeding strategies to incorporate salt tolerance traits from Thinopyrum into wheat.

Item Type

ethesis

Thesis Type

PhD

Supervisors

Grewal, Surbhi