Selection Of Salinity-Tolerant Wheat (Triticum Aestivum L.) Lines To Improve Production Yields Under Climate Change

Abstract

This study aimed to identify salinity-tolerant wheat genotypes under conditions of salt stress in irrigation water, particularly in regions like Iraq affected by soil and irrigation water salinization. Twenty-three bread wheat (Triticum aestivum L.) genotypes were evaluated under three salinity levels (5, 10, and 15 dS·m⁻¹) in a split-plot design during the two seasons 2022-2024. Morphological (yield per m², biomass, flag leaf area, 1000 grain weight) and physiological traits (chlorophyll content, proline accumulation, Na⁺/K⁺ ratio) were measured. Molecular analysis involved SSR markers (Xcfd-18 and Xgwm-493) to identify genetic loci associated with salinity tolerance, followed by Sanger sequencing of selected genotypes. Results revealed significant genotypic variation in salinity tolerance. Tolerant genotypes (NF, SA, TB, UD) exhibited minimal yield reduction (12–19%) at high salinity, while sensitive genotypes ones (VN, PB) showed severe declines (up to 77%). Physiological markers, including higher proline content and balanced Na⁺/K⁺ ratios, correlated with tolerance. SSR markers distinguished tolerant genotypes, and sequencing confirmed homology with stress-resilient (Triticum turgidum durum). Four genomic sequences were deposited in NCBI (PP873642–PP873645). The study demonstrates the potential of integrating phenotypic and genotypic screening for developing salt-tolerant wheat varieties, supporting sustainable agriculture in salinity-affected regions.