Drought stress is one of the most significant abiotic stresses on the sustainability of global agriculture. The finding of natural resources is essential for decreasing the need for artificial fertilizers and boosting plant growth and yield under water stress conditions. This study used a factorial experimental design to investigate the effects of oak leaf extract, biofertilizer, and soil containing oak leaf powder on the growth and biochemical parameters of four tomato genotypes under water stress throughout the pre-flowering and pre-fruiting stages of plant development. The experiment had two components. The first component represented the genotypes (two sensitive and two tolerant), while the second component represented the treatment group, which included irrigated plants (SW), untreated and stressed plants (SS), treated plants with oak leaf powder and stressed (SOS), treated plants with oak leaf powder and oak leaf extract and stressed (SOES), and treated plants with oak leaf powder and biofertilizers and stressed (SOBS). When compared with irrigated or control plants, drought stress under the treatments of SS, SOS, SOES, and SOBS conditions at two stages and their combination significantly lowered shoot length (12.95%), total fruit weight per plant (33.97%), relative water content (14.05%), and total chlorophyll content (26.30%). The reduction values for shoot length (17.58%), shoot fresh weight (22.08%), and total fruit weight per plant (42.61%) were significantly larger in two sensitive genotypes compared with tolerant genotypes, which recorded decreasing percentages of 8.36, 8.88, and 25.32% for shoot length, shoot fresh weight, and total fruit weight per plant, respectively. Root fresh weight and root dry weight of genotypes treated with SS, SOS, SOES, and SOBS, on the other hand, increased in comparison with control plants. Tomato fruits from stressed plants treated with SS, SOS, SOES, and SOBS had considerably higher levels of titratable acidity, ascorbic acid, and total phenolic compounds than irrigated plants during all stress stages. Under water stress conditions, the addition of oak leaf powder to soil, oak leaf extract, and biofertilizer improved the biochemical content of leaves in all genotypes. Furthermore, leaf lipid peroxidation was lower in plants treated with SOES and SOBS, and lower in the two tolerant genotypes than in the two susceptible genotypes. In conclusion, the application of SOS, SOES, and SOBS demonstrated a slight decrease in some morpho-physiological and fruit physicochemical traits compared with SS treatment. However, the application of oak leaf powder and oak leaf extract can be described as novel agricultural practices because they are low-cost, easy to use, time-consuming, and can meet the growing demands of the agricultural sector by providing environmentally sustainable techniques for enhancing plant resistance to abiotic stress. The usage of the combination of leaf crude extract, oak leaf powder, and arbuscular mycorrhizal fungus should be investigated further under stress conditions.

Among abiotic stresses, drought influences plant growth and productivity, and plant stress responses depend on stress intensity and genotype. The effects of simulated drought stress on germination parameters were tested for tolerance and sensitivity in 59 barley accessions from all regions of Iraq and phenotypic, physiological, and biochemical responses associated with drought stress were investigated. Stress treatments with polyethylene glycol (PEG) reduced the germination rate and dramatically delayed the development of the seedlings. Significant changes in the physiological and biochemical profiles in barley accessions were observed. A smaller reduction in water absorption of seeds was observed across all accessions, while all biochemical characteristics except total flavonoid content were increased with the increase in water deficiency in most accessions. Among the 59 barley accessions, ABN was the most tolerant accession, while Black-Garmiyan was the most drought-prone. Significant relationships were found between most trait pairs, with 24 significant associations under no stress, 39 significant correlations under the 10.25% PEG treatment, and 60 significant correlations under the 20.50% PEG treatment. According to the key importance analysis, seed water uptake, total phenol content, soluble sugar content, and catalase are classified as relative significance traits for germination percentage, root and shoot length under stress conditions.

Drought is one of the major abiotic stresses that affect plant growth and productivity, and plant stress responses are affected by both the intensity of stress and genotype. In Iraqi Kurdistan, tomato plants play a significant role in the country’s economy. Due to climate change, which causes soil moisture to diminish, the crop’s growth and yield have been dropping in recent years. Accordingly, the effects of simulated drought stress on germination parameters were assessed in 64 tomato accessions gathered from the Iraqi Kurdistan region in order to identify sensitive and tolerant accessions. In this respect, the responses associated with drought stress were observed phenotypically and biochemically. Germination percentage (GP) and morphological characteristics such as root length (RL), shoot length (SL), and shoot fresh weight (SFW) were significantly reduced in both stress treatments with polyethylene glycol (PEG-6000) (7.5% PEG and 15% PEG). On the other hand, significant changes in biochemical profiles such as proline content (PC), soluble sugar content (SSC), total phenolic content (TPC), antioxidant activity (AC), guaiacol peroxidase (GPA), catalase (CAT), and lipid peroxidation (LP) in tomato accessions were detected; all biochemical traits were increased in most tomato accessions under the PEG-induced treatments compared to the control treatment (0.0% PEG). Three tomato accessions (AC61 (Raza Pashayi), AC9 (Wrdi Be Tow), and AC63 (Sandra)) were found to be the most tolerant accessions under all drought conditions, whereas the performances of the other tested accessions (AC13 (Braw), AC30 (Yadgar), and AC8 (Israili)) were inferior. The OMIC analysis identified the biomarker parameters for differentiating the highly, moderately, and low tolerant groups as PC, SSC, and TPC. This study shows that early PEG-6000 screening for drought stress may help in choosing a genotype that is suitable for growth in water-stressed environments. Hence, Raza Pashayi, Wrdi Be Tow, and Sandra accessions, which had great performances under drought conditions, can be candidates for selection in a breeding program to improve the growth of plants and production in the areas that face water limits.

Barley (Hordeum vulgare L.) is the preferred crop in arid regions, particularly for farmers with limited agricultural resources and low income. Typically, it is utilized for human consumption, animal feed, and malting. The discovery of natural (organic) sources of biostimulants has attracted a great deal of interest for crop productivity enhancement. Using a randomized complete block design with three main blocks, it was our aim to investigate the effects of foliar moringa (Moringa oleifera L.) organ extract (MOE) on the growth and yield components of a collection of barley accessions grown in Iraq. As indicated by the obtained results, almost all traits associated with barley growth and yield productivity were significantly enhanced by MOE application, relative to the respective control condition. The majority of barley accessions responded positively to the MOE treatment based on all studied traits (with the exception of 1000-kernel weight). According to the results of principal component analysis (PCA), the distribution of accessions on the two components under the MOE application was distinct from the distribution of accessions under control conditions, indicating that accessions responded differently to the MOE application. In addition, the distribution pattern of traits under MOE treatment was comparable to the distribution pattern of traits under the control condition, with the exception of two traits: total yield and 1000-kernel weight. AC5 and AC18 responded positively to the MOE application by possessing the highest total yield and harvest index values. The total yield trait registered the highest increasing value index (37.55%) based on the trait response index, followed by the straw weight (22.29%), tillering number per plant (21.44%), and spike number per plant (21.36%), while the spike length trait registered the lowest increasing value index (0.45%), compared to the traits under control conditions. So far, the results indicate that foliar application of MOE can be utilized effectively as a natural growth promoter to increase the growth and yield productivity of grown barley accessions.

All parts of the hawthorn tree (Crataegus spp.), including fruits, flowers, and leaves, have been used as a source of bioactive compounds. Thus, in this investigation, the twigs of two species of hawthorn plant of Crataegus azarolus (C. azarolus) and Crataegus monogyna (C. monogyna) were evaluated for bioactive compositions and biological activity (antioxidant and antimicrobial activities). To evaluate bioactive compositions, high-performance liquid chromatography (HPLC) was applied, and for biological activity, biochemical assays were performed. C. monogyna revealed a higher amount of total phenolic, total flavonoid, and total tannin contents compared to C. azarolus. The HPLC results indicated the highest amount of kaempferol (14.40%), catechin (17.70%), and gallic acid (25%) in twigs of C. azarolus, while the maximum quercetin (72%) compound was present in C. monogyna. C. monogyna exhibited higher antioxidant activity by 1,1-dizarophenyl-2-picrylhydrazyl (DPPH) (86.13%) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (92.93%) compared to C. azarolus for antioxidant activity-DPPH (81.86%) and -ABTS (87.47%) assay. In the case of antimicrobial activity, the twigs of both species (especially C. azarolus) have a capacity against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus. The results of this study revealed that the twigs of both species contained a high amount of phenolic metabolites and antioxidant activity, while they showed low antimicrobial activity.