Screening Spring Wheat Genotypes for TaDreb-B1 and Fehw3 Genes under Severe Drought Stress at the Germination Stage Using KASP Technology

Abstract

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.

Effectiveness of TaDreb-B1 and 1-FEH w3 KASP Markers in Spring and Winter Wheat Populations for Marker-Assisted Selection to Improve Drought Tolerance

“…Germination is a growth stage before the seedling stage. No significant association was identified between the two KASP markers and germination traits (germination %, germination rate, shoot length, root length, number of roots, fresh and dry weight, and water content) under severe drought stress induced by PEG [17]. Additionally, no clear allele effect, on average, regarding drought tolerance, was found for all traits under both PEG treatments.…”

“…It could be that the other genotypes that did not have the target allele include other drought-tolerant genes. In wheat, the negative and non-significant effect of the C allele of the 1-FEWHw3 gene was found at the germination stage [17] and also at the adult growth stage in a large number of highly diverse wheat genotypes [16]. The SNP alleles of 1-FEH w3 were reported by Zhang et al [32].…”

“…Unfortunately, very few studies have investigated the effect of these two KASP markers on drought tolerance in the field. Mohamed et al [17] tested the association between the two KASP markers and germination traits in wheat under 25 and 30% of polyethylene glycol (PEG). The association between yield traits under normal conditions and these two markers was studied by Rehman et al [16].…”

“…KASP is rarely used to investigate the effects of drought on wheat at the seedling stage, two KASP markers, namely TaDreb-B1 and 1-FEH w3 from Dreb and Fehw3 genes, were reported with their association with drought tolerance [15]. Only two studies tested these markers with their association with yield under normal conditions and drought tolerance at the germination stage, and those studies were by Rehman et al [16] and Mohamed et al [17], respectively. Therefore, insufficient information is provided about these two markers for drought tolerance to be used in MAS, in which big germplasm can be screened.…”

Genome‐wide scanning to identify and validate single nucleotide polymorphism markers associated with drought tolerance in spring wheat seedlings

“…Drought stress can occur at any stage of plant growth, depending on the environmental conditions (A. A. M. Ahmed, Dawood, et al., 2022; Mohamed et al., 2022). Furthermore, drought stress differently affects genotypes depending on their severity, duration, and the growth stage in which it occurs (Omar et al., 2023).…”