Stripe rust (incited by Puccinia striiformis f. sp. tritici) is airborne wheat (Triticum aestivum L.) disease with dynamic virulence evolution. Thus, anticipatory and continued screening in hotspot regions is crucial to identify new pathotypes and integrate new resistance resources to prevent potential disease epidemics. A global wheat panel consisting of 882 landraces and 912 improved accessions was evaluated in two locations in Egypt during 2016 and 2017. Five prevalent and aggressive pathotypes of stripe rust were used to inoculate the accessions during the two growing seasons and two locations under field conditions. The objectives were to evaluate the panel for stripe rust resistance at the adult plant stage, identify potentially novel QTLs associated with stripe rust resistance, and validate previously reported stripe rust QTLs under the Egyptian conditions. The results indicated that 42 landraces and 140 improved accessions were resistant to stripe rust. Moreover, 24 SNPs were associated with stripe rust resistance and were within 18 wheat functional genes. Four of these genes were involved in several plant defense mechanisms. The number of favorable alleles, based upon the associated SNPs, was significant and negatively correlated with stripe rust resistance score, i.e., as the number of resistances alleles increased the observed resistance increased. In conclusion, generating new stripe rust phenotypic information on this panel while using the publicly available molecular marker data, contributed to identifying potentially novel QTLs associated with stripe rust and validated 17 of the previously reported QTLs in one of the global hotspots for stripe rust.

Barley (Hordeum vulgare L.) thrives in the arid and semi-arid regions of the world; nevertheless, it suffers large grain yield losses due to drought stress. A panel of 426 lines of barley was evaluated in Egypt under deficit (DI) and full irrigation (FI) during the 2019 and 2020 growing seasons. Observations were recorded on the number of days to flowering (NDF), total chlorophyll content (CH), canopy temperature (CAN), grain filling duration (GFD), plant height (PH), and grain yield (Yield) under DI and FI. The lines were genotyped using the 9K Infinium iSelect single nucleotide polymorphisms (SNP) genotyping platform, which resulted in 6913 high-quality SNPs. In conjunction with the SNP markers, the phenotypic data were subjected to a genome-wide association scan (GWAS) using Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK). The GWAS results indicated that 36 SNPs were significantly associated with the studied traits under DI and FI. Furthermore, eight markers were significant and common across DI and FI water regimes, while 14 markers were uniquely associated with the studied traits under DI. Under DI and FI, three (11_10326, 11_20042, and 11_20170) and five (11_20099, 11_10326, 11_20840, 12_30298, and 11_20605) markers, respectively, had pleiotropic effect on at least two traits. Among the significant markers, 24 were annotated to known barley genes. Most of these genes were involved in plant responses to environmental stimuli such as drought. Overall, nine of the significant markers were previously reported, and 27 markers might be considered novel. Several markers identified in this study could enable the prediction of barley accessions with optimal agronomic performance under DI and FI.

Wheat (Triticum aestivum L.) uptakes only 40 to 60% of the soil available nitrogen. Sulfur deficiencies depress both nitrate uptake and nitrate reductase activity resulting in low nitrogen use efficiency. Soil and foliar supplied sulfur in combinations with foliar nitrogen were used on three of the modern and commercially grown wheat cultivars. The experiment was conducted in two consecutive growing seasons; 2017 and 2018 in a high pH soil, 8.55. Our results indicated that 714 kg ha^-1 of pre-planting sulfur (SS) and spraying twice with 6.66% urea and 2.2% micronized sulfur (S₁FS₁N₁) during stages 13 & 41 on Zadok`s scale, increased grain yield, total protein content, straw yield and plant height by 31.58, 26.09, 18.37 and 7.9% respectively. The results indicated a significant and positive impact sulfur-nitrogen combinations when applied on top of pre-planting applied sulfur. However, foliar sprayed sulfur had a more substantial effect on all traits, compared to the pre-planting sulfur or the foliar sprayed N, suggesting interference effect of the alkaline soil with the amount of sulfur recovered from the soil. When N and S foliar were applied simultaneously, a more substantial increase in grain yield, plant height, straw yield and total protein content was observed, suggesting a synergistic effect between these two elements. We attributed the positive effect of S₁FS₁N₁ on improving photosynthates translocation from the sources to sinks. In addition to improving nitrogen use efficiency while reducing the plant content of NO⁻³ by optimizing the S/N ratio and reducing sulfur deficiency. Based on our results, we concluded that the foliar application of micronized S has the potential to improve the overall performance of wheat plants. Thus, we recommend enriching nitrogen and phosphate fertilizers with sulfur for alkaline soils.