No abstract

Stripe rust is the most harmful and prevalent disease among global wheat genotypes worldwide. It is induced by Puccinia striiformis f. sp. tritici. Its disease can also create new physiological races that attack resistant genotypes and constitute a severe danger to wheat output. The improvement of genetic resistance using Yr's genes through breeding programs that were not previously operated in Egypt in wheat genotypes is an effective strategy for preventing the disease. The marker-assisted selection with PCR-based methods was used to characterize the degree of slow rusting resistance for 38 wheat genotypes to stripe rust. The findings on the slow rusting genes support the resistance in the genotypes and can be used in wheat breeding programs to produce new stripe rust-resistant genotypes. The genotypes were classified into three major categories based on four disease parameters. The first group consisted of resistant genotypes. The second group had the lowest values of disease parameters and slower rusting. The third group showed the highest values for the disease parameters, including fast-rust genotypes, over the course of three seasons. The results revealed that the Super Kauz, Opata/Pastor, PBW 343/KKU, Opata 58, Chuan Nong 19, and IRAG genotypes enclosing Yr5, Yr15, Yr33, Yr37, Yr34, Yr51, Yr57, Yr4BL, and Yrkk genes were so resistant to stripe rust. while the Misr 3, Misr 4, Giza 168, Giza 167, Giza 170, Giza 171, Gemmeiza-9, and Gemmeiza-10 genotypes have the Yr9 gene. Giza 168, Giza 170, Gemmeiza-9, Gemmeiza-10, and Sids-14, containing the Yr18 and Yr29 genes. while the Yr17 and Yr27 genes were present in the Sids 13 and the most virulent genotype, respectively. In the backcrossing program, the genes were integrated into susceptible wheat genotypes, and different BC generations were created. From susceptible genotypes, stripe rust affected Gemmeiza 11, Misr 1, and Sids 14. These genotypes have high importance for farmers; they are cultivated in large areas worldwide, and the quality of their flour is high. Therefore, we intergraded Yr5 and Yr10 genes into these three genotypes using a breeding program. Finally, the characteristic of resistance improved and the high-yield production increased in studied wheat genotypes.

Powdery mildew disease, caused by Erysiphe betae, is one of the most threatening diseases on sugar beet plants worldwide. It causes a great loss in the root yield, sugar percentage, and quality of produced sugar. In the current study, we aimed to evaluate the susceptibility of 25 sugar beet cultivars to infection with powdery mildew disease under Egyptian conditions. Moreover, we evaluated the impacts of three eco-friendly materials, including potassium bicarbonate (KHCO3; at 5 and 10 g L−1), Moringa oleifera seed extract (25 and 50 g L−1), and the biocontrol agent, Bacillus subtilis (108 cell suspension) against E. betae in two successive seasons 2020 and 2021. Our findings showed that there were significant differences between these 25 cultivars in their susceptibility to the disease under study. Using the detached leaves technique in vitro, B. subtilis showed strong antifungal activity against E. betae. Moreover, both concentrations of KHCO3 and moringa seed extract significantly reduced the disease severity. Under field conditions, tested treatments significantly reduced the severity of powdery mildew disease and prevented E. betae from producing its conidiophores and conidia. Scanning electron microscope examination of treated leaves demonstrated the presence of the decomposition of fungal hyphae, conidiophores, conidia, and the occurrence of plasmolysis to fungal cells and spores on the surface of the leaves. Furthermore, these treatments greatly improved the percent of sucrose and soluble solids content, as well as the enzymatic activity of peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase. It is noteworthy that treatment with moringa seed extract gave the best results, followed by potassium bicarbonate, then B. subtilis cell suspension. Generally, it is recommended to use the substances used in this research to combat powdery mildew to minimize or prevent the use of chemical fungicides harmful to public health and the environment.

Fusarium verticillioides, an important maize pathogen, produce fumonisins, causes stalk rot and consequentially reduce crop growth and yield. Therefore, herein we aimed to evaluate the potential use of two farmyard soil organic manures, i.e., fresh (5-6 days old) and stored (5-6 months old) organic manure, to manage F. verticillioides infections as well as borer incidence and lodging in maize plants. After 30, 60, and 90 days of sowing, samples of soil, roots, and stems were collected to isolate F. verticillioides. Moreover, we estimated ear and kernel rot induced by F. verticillioides at the final harvest. Fresh organic manure treatment increased infection rates of F. verticillioides in soil, roots, stem and kernels compared to the control treatment. In contrast, stored organic manure plots treatments decrease F. verticillioides frequency. At 90 days after sowing, stored organic manure suppressed the survival of F. verticillioides, which reduced the F. verticillioides incidence percent. These results were similar to the effect of herbicides-and insecticide-treated plots demonstrated, which show a significant decrease in F. verticillioides incidence rates. Mycological analysis on symptomless kernels revealed a higher % of pathogen infection in opened husks variety (Balady) than closed husks variety (SC10). Compared with stored organic manure, the stem borer incidence and lodging percentage were the highest in fresh organic manure plots. Finally, these results demonstrated that storing organic manure within five to six months as farmyard manure led to high-temperature centigrade within organic manure, thereby destroying spores of F. verticillioides, whereas fresh organic manure did not.

Puccinia striiformis Westend is an obligate parasite, has the capabilities to infect wheat (Triticum aestivum) and barley (Hordeum vulgare) causing yellow (stripe) rust, which is extremely a very dangerous disease. Several formae specialis of the rust fungus P. striiformis, including P. striiformis f.sp. tritici (Pst) and P. striiformis f.sp. hordei (Psh), are classified based on host specialization. In 1920, P. striiformis f.sp. tritici (Pst), which causes wheat stripe rust, was discovered for the first time in Egypt (Briton-Jones, 1920 andBriton-Jones, 1925). In 2022, wheat varieties, Gemmeiza-11, Sids-12, Misr-1 and Misr-2 are susceptible to yellow rust, meantime symptoms of yellow rust caused by P. striiformis f.sp. tritici were observed on barley line,