Due to the advances in DNA markers, kompetitive allele-specific PCR (KASP) markers could accelerate breeding programs and genetically improve drought tolerance. Two previously reported KASP markers, TaDreb-B1 and 1-FEH w3, were investigated in this study for the marker-assisted selection (MAS) of drought tolerance. Two highly diverse spring and winter wheat populations were genotyped using these two KASP markers. The same populations were evaluated for drought tolerance at seedling (drought stress) and reproductive (normal and drought stress) growth stages. The single-marker analysis revealed a high significant association between the target allele of 1-FEH w3 and drought susceptibility in the spring population, while the marker–trait association was not significant in the winter population. The TaDreb-B1 marker did not have any highly significant association with seedling traits, except the sum of leaf wilting in the spring population. For field experiments, SMA revealed very few negative and significant associations between the target allele of the two markers and yield traits under both conditions. The results of this study revealed that the use of TaDreb-B1 provided better consistency in improving drought tolerance than 1-FEH w3.

Drought stress is a major yield-limiting factor throughout the world in wheat (Triticum aestivum L.), causing losses of up to 80% of the total yield. The identification of factors affecting drought stress tolerance in the seedling stage is especially important to increase adaptation and accelerate the grain yield potential. In the current study, 41 spring wheat genotypes were tested for their tolerance to drought at the germination stage under two different polyethylene glycol concentrations (PEG) of 25% and 30%. For this purpose, twenty seedlings from each genotype were evaluated in triplicate with a randomized complete block design (RCBD) in a controlled growth chamber. The following nine parameters were recorded: germination pace (GP), germination percentage (G%), number of roots (NR), shoot length (SL), root length (RL), shoot–root length ratio (SRR), fresh biomass weight (FBW), dry biomass weight (DBW), and water content (WC). An analysis of variance (ANOVA) revealed highly significant differences (p < 0.01) among the genotypes, treatments (PEG25%, PEG30%) and genotypes × treatment interaction, for all traits. The broad-sense heritability (H²) estimates were very high in both concentrations. They ranged from 89.4 to 98.9% under PEG25% and from 70.8 to 98.7% under PEG30%. Citr15314 (Afghanistan) was among the best performing genotypes under both concentrations for most of the germination traits. Two KASP markers for TaDreb-B1 and Fehw3 genes were used to screen all genotypes and to study the effect of these on drought tolerance at the germination stage. All genotypes with Fehw3 (only) showed a better performance for most traits under both concentrations compared to other genotypes having TaDreb-B1 or having both genes. To our knowledge, this work is the first report showing the effect of the two genes on germination traits under severe drought stress conditions.