Search Results (9)

Powdery mildew, caused by Blumeria graminis f. sp. hordei (Bgh), severely impacts global barley Hordeum vulgare L. (Hv) production. This investigation evaluated Egyptian barley genotypes to identify novel resistance sources and molecular markers for breeding programs. Phenotypic assessments at the seedling (growth stage, GS 32) and adult plant (GS 55–59) stages under controlled and field conditions, combined with SSR marker analysis, revealed distinct resistance profiles. Genotypes Giza 123, Giza 125, and G8 exhibited strong resistance, with Giza 123 displaying Mlo-mediated immunity. Susceptible genotypes (Giza 126, G1, G2, and G4) showed rapid disease progression (IT4; up to 80% severity). Intermediate genotypes (G5, G6, and G9) suggested quantitative resistance. Simple sequence repeat (SSR) analysis linked the EBmac0603 primer 160 bp allele to resistance and the 149 bp allele to susceptibility. The EBmac0603 primer 185 bp allele correlated with partial resistance, highlighting its utility in marker-assisted selection (MAS). The integration of phenotypic and molecular data identified Giza 123 and G8 as prime candidates for breeding, emphasizing the need for strategies like gene pyramiding or quantitative resistance incorporation in susceptible lines. This study underscores the value of Egypt’s barley diversity in advancing durable disease resistance through targeted breeding and molecular tools. Full article

Climate change significantly threatens crops, mainly through drought stress, affecting barley, which is essential for food and feed globally. Ten barley cultivars were evaluated under normal and drought stress conditions during the 2019/20 and 2020/21 seasons, focusing on traits such as days to heading and maturity, plant height, number of spikes m⁻², spike length, 1000-kernel weight, and biological and grain yield. Drought stress significantly reduced most of these traits. The genotypes showed significant differences in their responses to irrigation treatments, with the interaction between seasons and cultivars also being significant for most traits. The grain yield and 1000-kernel weight were among the least affected traits under drought stress, respectively. Notably, Giza138 and Giza126 showed strong drought tolerance, suitable for drought-resilient breeding. In season one, Giza126, Giza134, and Giza138 yielded 13%, 9%, and 11%, respectively, while Giza135 and Giza129 showed higher reductions at 31% and 39%. In season two, Giza126, Giza134, and Giza138 had reductions of 14%, 10%, and 13%, respectively, while Giza135 and Giza129 again exhibited higher reductions at 31% and 38%. These cultivars also showed strong performance across various stress tolerance indices, including the MP, YSI, STI, GMP, and YI. Giza 134 demonstrated the lowest values for the SDI and TOL, indicating superior drought stress tolerance. On the other hand, Giza 129 and Giza 135 were the most sensitive to drought stress, experiencing significant reductions across critical traits, including 6.1% in days to heading, 18.37% in plant height, 28.21% in number of kernel spikes⁻¹, 38.45% in grain yield, and 34.91% in biological yield. In contrast, Giza 138 and Giza 2000 showed better resilience, with lower reductions in the 1000-kernel weight (6.41%) and grain yield (10.61%), making them more suitable for drought-prone conditions. Giza 126 and Giza 132 also exhibited lower sensitivity, with minimal reductions in days to heading (2%) and maturity (2.4%), suggesting potential adaptability to water-limited environments. Giza 126 maintained the highest root lengths and had the highest stomatal conductance. Giza 138 consistently had the highest chlorophyll content, with SPAD values decreasing to 79% under drought. Despite leading in shoot length, Giza 135 decreased to 42.59% under drought stress. In conclusion, Giza 126 and Giza 138 showed adaptability to water-limited conditions with minimal impact on phenological traits. Giza 126 had the longest roots and highest stomatal conductance, while Giza 138 consistently maintained a high chlorophyll content. Together, they and Giza 134 are valuable for breeding programs to improve barley drought tolerance. Full article

The present study aimed to evaluate the potential of improving the feeding value of Egyptian clover (EC), ryegrass (R), triticale (T), barley (B), and oats (O) monoculture, or Egyptian clover mixed with ryegrass (EC+R), oats (EC+O), barely (EC+B), and triticale (EC+T) at 75:25% seeding rate, respectively, during two successive winter seasons of 2018/19 and 2019/20. Harvesting of plots was carried out at 5 cm stubble height after 60, 100, and 140 days from sowing. The in vitro nutritive value and ruminal fermentation of the monoculture and intercropping containing EC were evaluated. Green forage yield of EC was higher than other plants with about 160% of fresh forage compared with T, O, or EC+T intercropping. The highest crude protein (CP) concentration was noted in EC, while the lowest (p < 0.001) concentration was observed in T, which had the highest fiber fractions content. Ryegrass had the highest net in vitro gas production (GP), while EC+R had the lowest GP (p < 0.05). The EC increased dry matter and organic matter degradability. EC and R reduced protozoal count, while total volatile fatty acids (VFA), acetate, and propionate were increased with B and EC+T intercropping (p < 0.05). Overall, intercropping of EC with grass of triticale or ryegrass at mixing rates of 75:25% resulted in improving fresh and dry forage yields. The legume–grass intercropping improved the protozoa count partitioning factor as an index of microbial protein synthesis and total VFA concentration. Full article

The biochar application can improve the physiochemical properties of both sandy and clayey loam soils and is considered a potential adaptation tool toward climate change. Therefore, the current study is novel in combining water-hyacinth-derived biochar with organic manures as a suggested effective way of treating the soil with biochar under arid and semiarid conditions. Water hyacinth weeds were slow pyrolyzed at a temperature of 300 °C, which resulted in nonalkaline biochar with a pH value of 6.31, which is suitable for alkaline soils. A pot experiment was established to study the impact of the solo application of nonalkaline water-hyacinth-derived biochar (WHB) and its combined application with farmyard (WHB/FM) and poultry manure (WHB/PM) at a rate of 1.5 and 3%, respectively, on some chemical and physical properties of sandy and clay loam soils and some barley’s growth parameters. WHB, WHB/FM, and WHB/PM significantly affected the soil pH at different application rates (1.5 and 3%) in sandy soil. A considerable alteration in water-stable aggregates (WSA), dispersion ratio (DR), available water content (AWC), and cation ratio of soil structural stability (CROSS) index resulted from combining manures (FM and PM) with biochar better than the solo application of biochar. WHB/PM treatments had a superior effect in improving barley’s growth. Relative increases were by 37.3 and 11.0% in plant height and by 61.6 and 28.5% in the dry matter in sandy and clayey loam soils, respectively. Under the conditions of this study, we can conclude that treating the soil with WHB/PM at a rate of 1.5 and 3% is the most effective application. The current study may have a vital role in Egyptian agriculture sustainability by enhancing the soil characteristics of the old agricultural and the newly reclaimed lands. Full article

Loose smut (LS) disease is a serious problem that affects barley yield. Breeding of resistant cultivars and identifying new genes controlling LS has received very little attention. Therefore, it is important to understand the genetic basis of LS control in order to genetically improve LS resistance. To address this challenge, a set of 57 highly diverse barley genotypes were inoculated with Egyptian loose smut race(s) and the infected seeds/plants were evaluated in two growing seasons. Loose smut resistance (%) was scored on each genotype. High genetic variation was found among all tested genotypes indicating considerable differences in LS resistance that can be used for breeding. The broad-sense heritability (H²) of LS (0.95) was found. Moreover, genotyping-by-sequencing (GBS) was performed on all genotypes and generated in 16,966 SNP markers which were used for genetic association analysis using single-marker analysis. The analysis identified 27 significant SNPs distributed across all seven chromosomes that were associated with LS resistance. One SNP (S6_17854595) was located within the HORVU6Hr1G010050 gene model that encodes a protein kinase domain-containing protein (similar to the Un8 LS resistance gene, which contains two kinase domains). A TaqMan marker (0751D06 F6/R6) for the Un8 gene was tested in the diverse collection. The results indicated that none of the Egyptian genotypes had the Un8 gene. The result of this study provided new information on the genetic control of LS resistance. Moreover, good resistance genotypes were identified and can be used for breeding cultivars with improved resistance to Egyptian LS. Full article

The scarcity of water resources in arid and semi-arid areas is considered a threat to agricultural sustainability. Therefore, approaches are needed to rationalize use of irrigation water without reducing crop productivity or degrading soil properties. The objective of this study was to investigate the effect of different organic amendments (O₁ = control, O₂ = compost, and O₃ = vermicompost) combined with different rates of nano- zinc foliar spraying (Zn₁ = 0, Zn₂ = 1 and Zn₃ = 2 gm/L), under irrigation supplements (I₁ = 100%, I₂ = 85%, and I₃ = 65% of water requirements) on clay soil characteristics, on the production of Egyptian barley Giza 126. Over two successive winter growing seasons, 2018/2019 and 2019/2020, field experiments were conducted as a split-split plot design with three replications. The results show that using vermicompost is an appropriate organic amendment to improve the physical and chemical properties of soils as compared with compost. Application of vermicompost led to a reduction in soil salinity (ECe), exchangeable sodium percentage (ESP), and soil bulk density (BD), of −5.67%, −5.44%, and −2.21%, respectively; there was a significant increase in soil organic carbon (SOC), available nitrogen (A.N), and field capacity (F.C.), of 43.75%, 14.37%, and 18.65%, respectively, compared with unamended soil (O₁). The maximum values for grain yield were increased by 13.2% and 14.9% in both seasons, respectively, and the irrigation water productivity of barley was increased more than compost and control. Vermicompost increased the irrigation water productivity for grain (1.69 and 1.69 kg grain m⁻³) and straw (1.23 and 1.17 kg straw m⁻³) in the first and second season, respectively. Similar trends were also observed from treatments on the water applied, stored water, and water application efficiency. Application of vermicompost and nano-Zn foliar spraying could be exploited for the development of barley growth and yield, which are enhanced under water-saving irrigation strategies. Full article

Barley production is essential in Egypt. In the present study, 15 different six-rowed Egyptian barley cultivars were studied. To differentiate between the different cultivars under study in terms of morphological characteristics and ISSR, molecular characterization reactions were carried out. Moreover, four cultivars (Giza 123, Giza 126, Giza 136, and Giza 138) were selected for further studies using scanning electron microscopy (SEM). Computational analysis of the DNA barcoding sequences of the two plastid markers rbcL and matK was executed, and the results were deposited in the NCBI database. The morphological traits showed low statistical significance among the different cultivars under study via the data collected from two seasons, suggesting that the mean field performance of these Egyptian cultivars may be equal under these conditions. The results showed that the phylogenetic tree was divided into four groups, one of which contained the most closely related genotypes in the genetic distance, including Giza 124, Giza 130, Giza 138, Giza 136, and Giza 137, which converge in the indicative uses of farmers. The seed coat of the studied cultivars was “rugose”. The elevation folding of the rugose pattern ranged from 11 ± 1.73 µm (Giza 126) to 14.67 ± 2.43 µm (Giza 123), suggesting variation in seed quality and its uses in feed and the food industry. According to the similarity matrix of ISSR analysis, the highest similarity value (93%) was recorded between Giza 133 and Giza 132, as well as between Giza 2000 and Giza 126. On the other hand, the lowest similarity value (80%) was recorded between Giza 130 and (Giza 133 and Giza 132), indicating that these cultivars were distantly related. Polymorphism information content (PIC) ranged from 0.26 for the primer ISSR UBC 835 to 0.37 for the primers ISSR UBC 814 and ISSR UBC 840. The current study showed that the matK gene is more mutable than the rbcL gene among the tested cultivars. Full article

Heat stress is one of the abiotic stresses that cause a significant reduction in barley yield. Climate change will increase the number of heatwaves, which will result in more deterioration in the agricultural sector. Therefore, understanding the physiological changes that occur in the plant to tolerate heat stress is very important. A collection of 60 Egyptian spring barley genotypes has been tested for heat stress under field conditions. To quantify the changes in yield-related traits and the grain-reserve parameters as indicators for heat tolerance, several traits were scored. The causative genes that regulate the variation of all traits of interest were identified via single-marker analysis using 16,966 single nucleotide polymorphisms (SNP). Heat stress reduced yield-related traits, while some physiological traits (chlorophyll index, soluble carbohydrates, amino acids, and proline contents) increased. The genotypes were classified into four classes, A, B, C, and D, based on a reduction in grain yield per spike (GYPS) of 10%, 20%, 30%, and 40%, respectively. The physiological aspects were extensively studied in each group. The tolerant genotypes (class A) retained high yield-related traits as well as high reserved metabolites relative to the sensitive class D. The single-marker analysis and gene annotations revealed that the most effective markers and genes resided on chromosomes 1H and 4H. One of these markers, S4_250499621, was found to be associated with increased proline content, increased chlorophyll content, and decreased reduction in grain yield per spike and thousand kernel weight. This study is a part of our extended evaluation of this collection under various abiotic stresses at different developmental stages to develop climate-resilient crops. Full article

The aim of this study was to analyze the effect of ZnO nanoparticles (ZnO NPs) on the biogas production from mechanically treated barley straw and to perform a techno-economic analysis based on the costs assessment and on the results of biogas production. The structural changes of mechanically pretreated barley straw were observed using FTIR, XRD, TGA, and SEM. Additionally, both green ZnO NPs prepared from red alga (Antithamnion plumula) extract and chemically prepared ZnO NPs were characterized by FTIR, XRD, SEM, and TEM, surface area, and EDX. The results revealed that the biogas production was slightly improved by 14.9 and 13.2% when the barley straw of 0.4 mm was mechanically pretreated with 10 mg/L of both green and chemical ZnO NPs and produced 390.5 mL biogas/g VS and 385 mL biogas/g VS, respectively. On the other hand, the higher concentrations of ZnO NPs equal to 20 mg/L had an inhibitory effect on biogas production and decreased the biogas yield to 173 mL biogas/g VS, which was less than the half of previous values. It was also clear that the mechanically treated barley straw of 0.4 mm size presented a higher biogas yield of about 340 mL/g VS, in comparison to 279 mL biogas/g VS of untreated biomass. The kinetic study showed that the first order, modified Gompertz and logistic function models had the best fit with the experimental data. The results showed that the nanoparticles (NPs) of the mechanically treated barely straw are a suitable source of biomass for biogas production, and its yields are higher than the untreated barley straw. The results of the cost-benefit analysis showed that the average levelized cost of energy (LCOE), adopting the best treatments (0.4 mm + 10 mg/L ZnO), is 0.21 €/kWh, which is not competitive with the other renewable energy systems in the Egyptian energy market. Full article