Phenotypic and SSR marker-based selection of M4 bread wheat (Triticum aestivum L.) putative mutant lines adapted to limited water availability in Egypt

Abstract Background : Developing high-yielding bread wheat ( Triticum aestivum L.) cultivars adapted to limited water availability is a key strategy for sustaining wheat production in Egypt. Hypothesis and objectives : In this study, we hypothesized that mutant lines in M3 and M4 generations could combine high productivity under well-watered and water-stress conditions. The objectives were to identify promising mutant lines under both conditions and assess genetic diversity. Methods: Field experiments were implemented at Experimental and Research Station, Cairo University (clayey soil), Egypt during the 2022-2023 growing seasons. The experiments were arranged in a split-plot design with four replications. Agronomic traits included spike weight, spike yield, grains per spike, 1000-grain weight, spikes m-2 and grain yield. Heritability, GGE bıplot analysis, phenotypic and genotypic correlation coefficients, path analysis SSR markers were applied. Results and novelty : Significant differences (p ≤ 0.05) were observed for all traits. 12 lines exhibited high grain yield relative to the respective mother. High heritability and high genetic advance determined spikes m⁻² and grain yield as effective selection criteria to detect promising mutant lines. GGE bıplot analysis determined the mutant line Maryut-5100 as an ideal genotype, combining high productivity and stability performance. Grain yield was positive and significantly correlated with the studied traits. Path coefficient analysis confirmed that spike yield had the highest direct effect on grain yield, followed by spikes m-2. SSR markers detected novel genetic (Genetic similarity 0.520-0.880). Cluster analysis differentiated the mutant lines from their mother cultivars. Analysis of molecular variance (AMOVA) exhibited 86% of the total genetic variation reflected unique genomic alterations. The putative mutant lines, particularly Maryut-5100, were recommended for confirmation trials aimed at developing high-yielding wheat cultivars adapted to limited water availability.