82 © 2024 The Author(s). Published by College of Education for Pure Science (Ibn Al-Haitham), University of Baghdad. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License The Role of Foliar Nutrition in Tolerance of Wheat (Triticum aestivum L.) Varieties under Drought Stress Azhar Taher Sleibi 1* and Asaad Kadhim Abdullah 2 1,2 Department of Biology, College of Education for Pure Sciences (Ibn-Al-Haitham), University of Baghdad, Baghdad, Iraq. Received: 17 February 2025 Accepted: 8 May 2025 Published: 20 October 2025 doi.org/10.30526/38.4.4131 Drought is a major challenge in plant growth, significantly affecting the uptake and transport of essential nutrients such as iron, copper, magnesium, and zinc and leading to disruptions in physiological processes such as metabolism and reduced productivity. (1) Wheat (Triticum aestivum L.) is one of the most important cereal crops globally, cultivated on large areas and ranking first worldwide. Bread wheat is a staple food for millions, including the Iraqi population, and holds strategic importance in achieving food security (2). Drought water stress threatens wheat production, requiring strategies to enhance drought https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com https://orcid.org/0009-0009-0554-9987 mailto:azhar.Taher2202p@ihcoedu.uobaghdad.edu.iq https://orcid.org/0000-0001-7670-8003 mailto:drasaadkadhim@gmail.com IHJPAS. 2025, 38 (4) 83 tolerance. Micronutrients (Fe, Zn, Cu, and Mn) play crucial roles in metabolism and stress tolerance resistance by physiological and molecular mechanisms regulation (3). TThey improve seed germination, water use efficiency, membrane stability, stomatal regulation, and photosynthesis; they interact with hormones; they enhance stress protein expression; and they activate antioxidant enzymes (4, 5). Studies also indicate that applying iron and zinc in nanoparticle form, combined with bacterial and amino fertilizers, can further enhance drought tolerance in crops like wheat (6, 7). Drought stress increases reactive oxygen species (ROS) production, causing oxidative damage to lipids, proteins, and DNA. Antioxidants like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione neutralize ROS, preserving cellular functions. Water stress also triggers physiological and morphological changes (8), stimulating antioxidant enzyme activity in wheat (Triticum spp.) to enhance stress resistance. Drought stress acts as a primary physiological constraint that impairs water and nutrient uptake, disrupts stomatal regulation, and alters photosynthetic efficiency, ultimately leading to oxidative stress. These disruptions trigger significant changes in biochemical markers, such as antioxidant enzyme activities and osmolyte accumulation, and negatively impact agronomic traits, including grain yield, spike number, and biomass accumulation (9, 10). Moreover, studies have highlighted the roles of non- enzymatic antioxidants such as proline and α-Tocopherol in enhancing plant stress tolerance. These compounds maintain cellular water balance and protect membranes from free radical damage. Foliar spraying with α-Tocopherol has been shown to improve antioxidant activity and boost drought tolerance (11). Genetic variation also influences wheat varieties' ability to withstand water stress, guiding the selection of stress-resilient varieties with effective antioxidant traits (12).Despite extensive research on the physiological and biochemical effects of drought stress in wheat, there remains a lack of integrated studies that simultaneously evaluate genotype-dependent responses and the role of foliar micronutrient application in enhancing antioxidant defense mechanisms. This study addresses this gap by investigating the interactive effects of drought severity, genotype variation, and micronutrient supplementation on antioxidant activity and yield traits in wheat under controlled conditions. It is hypothesized that foliar application of Fe, Zn, Cu, and Mn will improve the biochemical and agronomic performance of drought-tolerant genotypes, particularly under severe water deficit. This study stands out because it looks at two stress factors at the same time, drought and lack of micronutrients, allowing for a clear understanding of how different wheat types respond when both stresses are present. It aims to analyze the interactive effects of these factors on yield-related traits and antioxidant activity (enzymatic and non-enzymatic) to identify the most tolerant genotypes and distinguish them from the sensitive ones. IHJPAS. 2025, 38 (4) 84 IHJPAS. 2025, 38 (4) 85 Table 1. Effect of drought, foliar application, varieties and interaction on yield characteristics and components of wheat IHJPAS. 2025, 38 (4) 86 IHJPAS. 2025, 38 (4) 87 3.2. Determination of enzymatic and non-enzymatic antioxidants Table 2 shows a significant increase in SOD enzyme activity under drought stress, reaching 76.04 (absorption unit.ml-¹) at 75% stress, compared to 31.89 at 25% stress, with a 138.44% increase. Enzyme activity was higher under non-addition of micronutrients (56.32 absorption unit.ml - ¹) than with addition (44.27 absorption unit.ml - ¹), increasing by 27.21%. Among varieties, Adna 99 showed the highest SOD activity (78.95 absorption unit.ml - ¹), significantly outperforming Wafia (18.76 absorption unit.ml - ¹) by 320.84%. Under 75% stress without micronutrients, Adna 99 recorded the highest activity (161.50 absorption unit.ml - ¹), while Wafia showed the lowest (15.00 absorption unit.ml - ¹). The results in Table 2 show a significant increase in POD under 75% stress (26.20 absorption unit.ml - ¹) compared to 25% stress (25.79 absorption unit.ml - ¹), with a 1.59% rise. Micronutrient application reduced enzyme activity (25.00 absorption unit.ml - ¹) compared to without-spraying (27.00 absorption unit.ml - ¹), showing an 8% increase. Adna 99 recorded the highest activity (30.33 absorption unit.ml - ¹), surpassing Wafia (18.64 absorption unit.ml - ¹) by 62.71%. Under 75% stress without spraying, Adna 99 showed the highest activity (35.30), while Wafia had the lowest (11.83) under the same stress with spraying. Table 2 shows a significant increase in CAT enzyme activity with higher stress levels, reaching (21.06 absorption unit.ml - ¹) at 75% stress compared to (11.61 absorption unit.ml - ¹) at 25% (81.40% rise). Enzyme activity was higher under non-spraying (16.51 absorption unit.ml-¹) than spraying (15.88 absorption unit.ml - ¹). Adna 99 recorded the highest activity (21.63 absorption unit.ml - ¹), while Wafia had the lowest (11.17 absorption unit.ml - ¹), with a 93.64% increase. The triple interaction showed Adna 99 under 75% stress without micronutrient addition had the highest value (33.24 absorption unit.ml - ¹), whereas Wafia under the same stress with addition had the lowest (10.11 absorption unit.ml - ¹). The result of Table 2 shows a significant increase in proline from 25% to 75% led to a significant increase in the average concentration of proline from 91.64 to 95.82 (μg.g -1 ) respectively, with an increase of 5%. The averages of micronutrients showed significant differences in proline concentration, increasing from 93.10 (μg.g - ¹) with spraying to 93.90 (μg.g - ¹) without spraying, a rise of 0.85%. The variety Adna 99 had the highest proline content (100.49 μg.g - ¹), while Wafia recorded the lowest 87 (μg.g - ¹), with a 15.51% increase. The triple interaction showed significant differences, as Adna 99 under 75% stress without spraying had the highest proline activity ,107.39 (μg.g - ¹), whereas Wafia under the same stress with spraying had the lowest, 85.01( μg. g - ¹). IHJPAS. 2025, 38 (4) 88 Table 2. Effect of drought, foliar application, varieties and interaction on antioxidants concentration of wheat. Parameters Treatments SOD unit. ml -1 POD unit. ml -1 CAT unit. ml -1 Proline μg. g - ¹ α-Tocopherol μg. g - ¹ Glycine Betaine μg. g - ¹ Variety Adna 99 78.95 30.33 21.63 100.49 27.14 65.90 Bohooth 22 53.16 29.01 15.79 93.01 22.56 61.06 Wafia 18.76 18.64 11.17 87.00 12.27 45.21 L. S. D 2.17 0.26 0.82 1.29 1.88 6.34 Drought SOD unit. ml -1 POD unit. ml -1 CAT unit. ml -1 Proline μg. g - ¹ α-Tocopherol μg. g - ¹ Glycine Betaine μg. g - ¹ D1 31.89 97.52 11.61 91.50 19.88 77.59 D2 42.95 92 15.92 93.04 20.24 77.72 D3 76.04 92.90 21.06 95.57 21.84 25.12 L. S. D 0.76 0.22 0.61 1.09 0.84 2.15 Micronutrients SOD unit. ml -1 POD unit. ml -1 CAT unit. ml -1 Proline μg. g - ¹ α-Tocopherol μg. g - ¹ Glycine Betaine μg. g - ¹ -M(with spry) 56.32 25.00 16.51 93.90 21.91 56.72 +M(without spry) 44.27 27.00 57.88 93.10 19.40 58.05 L. S. D 0.62 0.54 0.70 0.12 0.22 5.57 Vari*Drought*Micro SOD unit. ml -1 POD unit. ml -1 CAT unit. ml -1 Proline μg. g - ¹ α-Tocopherol μg. g - ¹ Glycine Betaine μg. g - ¹ Adna 99*D1*-M 23.50 26.66 11.22 97.19 28.57 59.08 Adna 99*D2*-M 89.50 32.43 21.32 100.33 28.65 62.80 Adna 99*D3*-M 161.50 35.30 33.24 107.39 30.98 77.11 Adna 99*D1*+M 54.40 27.83 10.68 96.21 19.34 50.13 Adna 99*D2*+M 38.00 28.16 20.20 99.35 25.55 59.19 Adna 99*D3*+M 106.75 31.65 33.13 102.09 29.77 87.10 Bohooth*D1*-M 31.50 25.83 12.38 90.62 23.15 58.80 Bohooth*D2*-M 64.25 32.86 16.00 91.31 20.16 63.15 Bohooth*D3*-M 80.25 32.43 20.12 96.90 30.45 69.47 Bohooth*D1*+M 34.50 26.50 11.46 90.23 20.67 57.71 Bohooth*D2*+M 31.25 25.61 15.44 93.39 22.73 56.92 Bohooth*D3*+M 77.25 30.86 19.35 95.66 18.12 60.32 Wafia*D1*-M 25.15 24.63 12.34 87.58 13.72 49.29 Wafia*D2*-M 16.25 17.75 11.56 85.90 11.23 38.40 Wafia*D3*-M 15.00 15.15 10.42 87.88 10.30 32.46 Wafia*D1*+M 22.19 23.33 11.60 87.67 13.86 55.73 Wafia*D2*+M 18.50 19.16 11.03 87.98 13.12 52.91 Wafia*D3*+M 15.50 11.83 10.11 85.01 11.42 42.52 L. S. D 31.87 4.63 1.50 2.67 5.07 8.26 The results shown in Table 2 show a significant increase in α-tocopherol when the level of water stress increased from 25% to 75%, if the concentration of α-tocopherol increased from 19.88 to 21.84 (μg.g -1 ) with an increase of 9.86%. Statistically significant differences were observed in α-tocopherol concentration due to micronutrient treatments, where spraying reduced its average from 21.91 (μg.g - ¹) to 19.40 (μg.g - ¹), a decrease of 12.9%. The variety Adna 99 recorded the highest concentration 27.14 (μg. g - ¹), while Wafia had the lowest at 12.27 (μg.g - ¹), with an increase of 121.18%. In the triple interaction, Adna 99 without spraying under 75% stress gave the highest value 30.98 (μg.g - ¹), while Wafia under the same conditions recorded the lowest of 10.30 (μg.g - ¹). Table 2 results show a significant increase with increasing drought (25% to 75%) raised glycine betaine concentration from 55.12 to 61.49 (μg. g - ¹), an 11.55% increase. Micronutrient application had a significant effect, as sprayed plants exhibited a higher IHJPAS. 2025, 38 (4) 89 glycine betaine concentration (58.05 μg·g - ¹) compared to non-sprayed plants (56.72 μg·g - ¹). Adna 99 recorded the highest concentration (65.90 μg. g - ¹), while Wafia had the lowest (45.21 μg.g - ¹). The triple interaction's highest concentration (87.10 μg.g - ¹) was recorded in the triple interaction of the sprayed Adna 99 variety under 75% water, while non-sprayed Wafia under the same stress had the lowest (32.46 μg.g - ¹). 3.3. Principal Component Analysis (PCA) Principal Component Analysis (PCA) reduces variables by summarizing data into key components, identifying major variance factors, simplifying analysis, and revealing patterns. Table 3 results show that PC1 strongly reflects growth and yield traits, with high positive loads on spikelet count (0.987), spike count (0.926), biological yield (0.969), and grain yield (0.941), making it a key yield indicator. PC2 captures stress response variability, linked to antioxidant enzymes CAT (0.789) and SOD (0.746). PC3, PC4, and PC5 contribute minimally, representing secondary traits. Table 3. Results of PCA for Five Principal Components of Study Traits under the Main Effects of Experimental Factors. Figure 1, which illustrates the five principal components derived from the analysis of the studied traits, indicates that the distribution of the wheat varieties varied across the principal components. The variety Adna 99 was represented in both PC1 and PC2, reflecting superior performance in both productivity and physiological traits under stress conditions, thereby confirming its high tolerance to drought and micronutrient deficiency. In contrast, the variety Bohooth 22 was positioned near the center of the plot, close to the intersection of the two axes, which may be interpreted as a balanced response in terms of yield performance and oxidative stress. The variety Wafia, on the other hand, was located in the quadrant associated with PC2, closer to traits linked with oxidative stress tolerance and farther from productivity- related traits. Regarding the levels of soil-available water depletion, the 75% treatment—representing the most severe water stress—was associated with physiological traits along PC2, indicating a clear activation of antioxidant responses. The 50% depletion level occupied an intermediate position, while the 25% treatment was located closer to yield-related traits on PC1, reflecting relatively optimal growing conditions. As for the effect of micronutrient application, the Trait PC1 PC2 PC3 PC4 PC5 CAT 0.582 0.789 0.173 0.052 -0.079 POD 0.913 0.255 -0.309 -0.075 0.002 SOD 0.657 0.746 0.051 -0.001 0.090 Proline 0.855 0.481 0.183 -0.063 -0.027 α-Tocopherol 0.921 0.355 -0.112 -0.112 0.024 Glycine betaine 0.877 0.438 -0.094 0.167 0.039 spike L. 0.949 -0.188 -0.242 0.016 -0.068 Grain N. 0.857 -0.489 0.152 -0.021 0.048 spike N. 0.926 -0.290 0.231 -0.070 0.011 spikelet N. 0.987 -0.129 0.073 0.043 -0.039 1000 grain 0.886 -0.450 0.041 0.103 0.000 Grain.Y 0.941 -0.338 -0.003 -0.005 0.005 B.Y 0.969 -0.241 0.003 -0.043 -0.043 H. index 0.916 -0.394 -0.051 0.032 0.044 Eigenvalues 10.870 2.699 0.328 0.074 0.030 Variance % 77.643 19.277 2.340 0.528 0.212 Cumulative % 77.643 96.920 99.260 99.788 100.000 IHJPAS. 2025, 38 (4) 90 spraying treatment aligned with enhanced productivity traits (PC1), highlighting the role of micronutrients in promoting growth and yield. In contrast, the non-sprayed treatment was positioned toward the physiological defense traits (PC2), indicating the activation of antioxidant pathways in the absence of nutrient supplementation. Figure 1. Two-Dimensional Plot of Principal Component Analysis (PCA) Illustrating the Relationship Between Studied Traits for Three Wheat Varieties Under + and - Micronutrient Treatments and Three Levels of Water Stress (25%, 50%, 75%) The results in Table 1 show that Adna 99 significantly outperformed the other varieties in yield characteristics, followed by Bohooth 22. The drought tolerance of these varieties is attributed to high gene expression of SOD and BADH, which neutralize free radicals and reduce oxidative stress. Resistance to micronutrient deficiencies may be linked to increased expression of genes like ZIP7, COP1, and DMAs, which enhance the absorption of zinc, iron, and copper, and improve nutrient uptake. While the variety Wafia showed the opposite of what was mentioned, as it exhibited a significant decrease in all studied yield traits, this aligns with previous studies conducted by Zhang et al. (24). High water stress reduces spike length, ear and grain numbers, grain yield, and harvest index by inhibiting photosynthesis and carbon metabolism, limiting nutrient accumulation, and increasing reactive oxygen species (ROS), which damage proteins and cell membranes (25). Furthermore, water stress reduces dry matter accumulation by limiting shoot and root growth, increasing toxic ion concentrations, and causing stomatal closure, which restricts nutrient absorption and disrupts vital processes, ultimately lowering biological yield (26). The study by Hashim et al. (27) confirmed that wheat tolerance to water stress and yield are linked to physiological efficiency, with micronutrients like Fe, Zn, Cu, and Mn playing key roles. Their deficiency under stress reduces photosynthesis, respiration, and enzyme regulation, leading to poor growth. However, micronutrient application improves yield by enhancing physiological processes, enzyme activity, energy production, and antioxidant function (28). Studies also confirm that spraying zinc and iron on soft wheat increases spike length and grain count per spike compared to untreated plants (29). Wang et al. (30) found that micronutrient availability enhances plant resource efficiency, improving growth and yield even under stress. Tolerant varieties regulate gene expression to maintain high yields despite water and micronutrient deficiencies. Adna 99 excelled across all water stress levels (25%, 50%, 75%), particularly under 75% stress without micronutrient addition, showing the highest yield traits. Bohooth 22 followed closely, while Wafia performed poorly. Adna 99’s resilience highlights its suitability for water-limited regions. Its superiority may stem from better micronutrient IHJPAS. 2025, 38 (4) 91 availability, which supports key enzymes (Cu/Zn-SOD), ferredoxin activity, chlorophyll synthesis, and electron transport efficiency. (31). The interaction of copper and manganese enhances plant resilience to water stress by improving metabolism, energy production, and cell protection, leading to increased spike length, spikelet number, and overall yield. (32). Yield-related traits such as grain yield, biological yield, number of spikelets per spike, and number of spikes per unit area are key contributors to overall wheat productivity, as they collectively determine the plant’s capacity to accumulate and allocate assimilates under both optimal and stress conditions. Adna 99's strong association with PC1, influencing yield, highlights its high productivity potential. The 1000-grain weight and harvest index also contribute to yield improvement (33). The 1000-grain weight boosts yield by increasing grain size, while the harvest index measures resource efficiency in yield production. Traits such as grain yield, biological yield, spikelet, and spike number align with PCA results, where Adana 99’s strong PC1 association underscores its yield potential. Wafia’s stress-response mechanisms confirm the trade-off between stress tolerance and productivity (34 -36). This supports the notion that balancing yield-improving traits with stress tolerance is crucial in breeding programs. Antioxidant enzyme activity is positively associated with plant tolerance to abiotic stress. In the present study, the variety Wafia exhibited a marked reduction in yield-related traits (PC1), accompanied by a significant increase in antioxidant-related traits (PC2). This indicates a physiological trade-off, where the plant allocates more resources to stress defense mechanisms at the expense of productivity. While such a strategy enhances survival under adverse conditions, it compromises yield efficiency. Therefore, identifying and selecting genotypes that maintain a balance between stress tolerance and high yield potential is essential for sustainable crop improvement. Recent studies, such as those (37), highlight the significance of genetic variability and the application of Principal Component Analysis (PCA) in discriminating drought-tolerant genotypes. These findings support the integration of PCA-based selection approaches into breeding programs aimed at improving crop resilience. Table 2 demonstrates that the variety Adna 99 significantly excelled in the effectiveness of enzymatic antioxidants, as the levels of defense enzymes increased compared to the rest of the varieties. This superiority is attributed to the high gene expression of SOD (superoxide dismutase), COP (copper transport 1), and ZIP (zinc/iron-regulated transporter-like protein). The SOD gene contributes to reducing oxidative damage and enhancing the plant’s ability to withstand water stress (38). The COP gene promotes the production of catalase (CAT), an enzyme responsible for eliminating hydrogen peroxide, thereby mitigating its toxic effects (39). Additionally, the ZIP gene enhances zinc uptake, which is essential for CAT activity, helping reduce ROS accumulation and protect cells from damage caused by dehydration and micronutrient deficiency (40). As shown in Table 2, high water stress (75%) increased enzymatic antioxidant activity (SOD, POD, CAT), which enhanced cellular defense and minimized oxidative damage. This activation helps neutralize ROS, thereby protecting proteins, lipids, and nucleic acids while maintaining the stability of critical physiological processes and improving drought tolerance (41). These findings are consistent with previous reports emphasizing the vital role of enzymatic antioxidants such as SOD and CAT in protecting plant cells against oxidative stress under drought conditions (42). The study conducted by Sun et al. (43) also confirmed that these enzymes are essential in ROS regulation and stress resilience. Micronutrients are crucial for the functionality of antioxidant enzymes. In their absence, oxidative stress intensified, stimulating a compensatory increase in enzyme activity. IHJPAS. 2025, 38 (4) 92 However, foliar application of micronutrients significantly reduced ROS levels and stabilized enzymatic activity (44). Under 75% water stress without micronutrient application, Adna 99 displayed higher levels of enzymatic antioxidants than Wafia, attributed to more robust gene expression. In contrast, Wafia exhibited weaker antioxidant responses, reflecting its susceptibility to combined drought and micronutrient deficiency stress. These results are in agreement with other studies highlighting the synergistic role of micronutrients in improving enzymatic antioxidant activity and enhancing drought tolerance (45). The results of Table 2 also showed that the variety Adna 99 significantly outperformed the other varieties in its content of non-enzymatic antioxidants, namely proline, α-tocopherol, and glycine betaine. This increase is attributed to the high gene expression of key regulatory genes responsible for the biosynthesis of these compounds, which enhance the plant’s ability to adapt to environmental stress. The elevated levels of non-enzymatic antioxidants contribute to the stabilization of cellular membranes and the protection of photosynthetic systems under drought conditions (46). These findings are in line with previous studies that have confirmed the role of alpha-tocopherol in binding free radicals and protecting them from harmful interactions with phospholipids in cell membranes, enhancing the stability of these membranes, and protecting photovoltaic systems within cells from oxidative damage (47). Proline accumulation increases osmotic negativity, aiding water balance, maintaining turgor pressure, protecting proteins and membranes, and enhancing drought adaptation while counteracting ROS damage (48). The BADH gene stimulates glycine betaine production, aiding water balance, protecting proteins from oxidation, and enhancing respiration and ion transport under stress. Studies confirm that α-tocopherol, glycine betaine, and proline levels increase with stress, improving drought tolerance and plant defense. (49) Glycine betaine and proline are crucial for drought tolerance, especially with microelement deficiencies. Glycine betaine maintains water balance, stabilizes membranes, and protects against oxidative damage from iron and zinc deficiencies. Proline accumulates with zinc and copper shortages, compensating for the lack of antioxidants by stabilizing membranes and protecting proteins. (50). This is consistent with other studies that have shown that non-enzymatic antioxidant deficiencies may cause an increase in plant sensitivity to water stress due to the plant's failure to form an appropriate defense response against ROS accumulation (51). In addition, microelements contribute to the regulation of many metabolic pathways and cellular signaling that enhance a plant's ability to adapt to water stresses, protect cell membranes from oxidation, and help convert ROS into harmless compounds, improving membrane stability and integrity (52). The results show that Adna 99 increases proline, α-tocopherol, and glycine betaine concentrations under 75% water stress without micronutrient spraying, indicating a strong defense response. In contrast, Wafia showed lower levels of these compounds, reflecting its sensitivity. These findings align with studies confirming that stress-tolerant varieties elevate non-enzymatic antioxidant compound levels to counteract cadmium stress effects (53). 5. Conclusion Availability revealed clear genotype-dependent variation. Adna 99 demonstrated the highest adaptive capacity, characterized by enhanced yield performance and antioxidant defense mechanisms. Bohooth 22 exhibited intermediate resilience, whereas Wafia showed pronounced sensitivity, suggesting a limited ability to mitigate oxidative damage under stress conditions. The application of micronutrients (Fe, Zn, Cu, and Mn) played a critical role in strengthening both enzymatic and non-enzymatic antioxidant systems, thereby contributing to IHJPAS. 2025, 38 (4) 93 improved physiological stability and yield potential under water-limited environments. These findings underscore the value of integrating foliar micronutrient strategies with tolerant genotypes to enhance wheat performance under drought. Future studies are recommended to explore gene-level regulatory mechanisms underlying antioxidant responses across diverse agro-ecological zones. Acknowledgment The author sincerely thanks Dr. Asaad Kadhim Abdullah for his valuable guidance during this doctoral thesis. Special appreciation is extended to the University of Baghdad, the College of Education for Pure Sciences (Ibn Al-Haitham), and the Department of Life Sciences for their support and provision of essential facilities. Gratitude also goes to the Department of Agricultural Research, Seed Testing and Certification, and the National Wheat Development Program in Iraq for supplying certified wheat seeds registered with the Ministry of Agriculture. Conflict of Interest The authors declare that they have no conflicts of interest regarding the publication of this research. Funding This research received no external funding. References 1. Singh H, Kingra PK, Pal RK, Singh S. Impact of abiotic stresses on wheat yield and strategies for mitigation: A comprehensive review. Agric Res J. 2024;61(2). http://dx.doi.org/10.5958/2395- 146X.2024.00022.8 2. Sleibi AT, Abdullah AK. Phenotypic, physiological and molecular changes of some wheat varieties under drought stress. Plant Sci Today. 2025;12(1):1–10. https://doi.org/10.14719/pst.5593 3. Hassan MU, Chattha MU, Khan I, Habib M, Khan TA, Aamer M, Nawaz M, Chattha MB. The critical role of zinc in plants facing the drought stress: A review. J Plant Nut. 2023; 46(2): 243– 257. https://doi.org/10.3390/agriculture10090396. 4. Mohammed MY, Al-Hayany EH. The effect of spraying with quercetin in some of the growth characteristics of cow peas (Vigna sinensis) exposed to drought stress. Biochem Cell Arch. 2020;20, Suppl. 2: 4335-4340,. https://connectjournals.com/03896.2020.20.4335. 5. Al-Saidi AH, Saltern KA. Effect of Interaction Between Phosphorus and Zink in Some Morphological Features of Two Varieties of Wheat Grown in Gypsum Soil. Ibn AL-Haitham J Pure Appl Sci. 2008; 21(3):37-55. https://www.jih.uobaghdad.edu.iq/index.php/j/article/view/1403. 6. Jones SE, Ayanlade T, Fallen B, Jubery TZ, Singh A, Ganapathysubramanian B, Sarkar S, Singh AK. Multi-sensor and multi-temporal high-throughput phenotyping for monitoring and early detection of water-limiting stress in soybean. Plant Phenome J. 2024;7(1):e70009. https://doi.org/10.1002/ppj2.70009. 7. Jaafar MF, Abdullah AK. Impact of interaction between nano particles and bacterial and amino fertilizers on growth and yield of wheat plant. Plant Arch. 2020;20(1). https://plantarchives.org/20- 1/2829-2835%20(6080).pdf. 8. Ding Z, Ali EF, Elmahdy AM, Ragab KE, Seleiman MF, Kheir AM. Modeling the combined impacts of deficit irrigation, rising temperature and compost application on wheat yield and water productivity. Agric Water Manag. 2021; 244:106626. https://doi.org/10.1016/j.agwat.2020.106626. http://dx.doi.org/10.5958/2395-146X.2024.00022.8 http://dx.doi.org/10.5958/2395-146X.2024.00022.8 https://doi.org/10.14719/pst.5593 https://doi.org/10.3390/agriculture10090396 https://connectjournals.com/03896.2020.20.4335 https://www.jih.uobaghdad.edu.iq/index.php/j/article/view/1403 https://doi.org/10.1002/ppj2.70009 https://plantarchives.org/20-1/2829-2835%20(6080).pdf https://plantarchives.org/20-1/2829-2835%20(6080).pdf https://doi.org/10.1016/j.agwat.2020.106626 IHJPAS. 2025, 38 (4) 94 9. Al-Samerria IK, Al-Ghrairi SM, Rahi HA. Induction of antioxidant enzymes in wheat (Triticum spp.) grown under salt stress. Baghdad Sci J. 2013;10(3):832-43. https://doi.org/10.21123/bsj.2013.10.3.832-843. 10. González-Villagra J, Rodrigues-Salvador A, Nunes-Nesi A, Cohen JD, Reyes-Díaz MM. Age- related mechanism and its relationship with secondary metabolism and abscisic acid in Aristotelia chilensis plants subjected to drought stress. Plant Physiol Biochem. 2018;124:136-145. https://doi.org/10.1016/j.plaphy.2018.01.010. 11. AL-Kareemawi IHK, AL-Kazzaz AGM. α-Tocopherol foliar application can alleviate the adverse effect of salinity stress on wheat plant, Triticum aestivum L. Biochem Cell Arch. 2019;19(2): 3495- 3499. http://dx.doi.org/10.35124/bca.2019.19.2.3495. 12. Abdul-Mageed AS, Al-Hashemi HS. Performance of some wheat genotypes at seedling stage to water stress. Iraq J Agric Res. 2017;22(1):29-40 https://www.iraqoaj.net/iasj/download/9b01ec7668b547ad. 13. Kovda VA, Hagan RM, Berg C. Irrigation, drainage and salinity: an international source book. Hutchinson/FAO/UNESCO, Lindon, UK; 1973.p.510. 14. Cvijanović V, Cvijanović G, Rajičić V, Marinković J, Đukić V, Bajagić M, Đurić N. Influence of different methods of application of effective microorganisms in nutrition of wheat on weight by 1000 grains, yield, and content of crude wheat proteins (Triticum sp). Cereal Res Commun. 2022;50(4):1259-68. https://doi.org/10.1007/s42976-021-00226-1. 15. Mitchell B, Armstrong I, Black M, Chapman J. Physiological aspects of sprouting and spoilage in developing Triticum aestivum L.(wheat) grains; 1980. 16. Jr WF, Fridovich I. Assaying for superoxide dismutase activity: some large consequences of minor changes in conditions. Analyt Biochemi. 1987;161(2):559-66. https://doi.org/10.1016/0003- 2697(87)90489-1. 17. Müftügil N. The peroxidase enzyme activity of some vegetables and its resistance to heat. J Sci Food Agric. 1985;36(9):877-880. https://doi.org/10.1002/jsfa.2740360918 18. Bergmeyer HU. Methods of enzymatic analysis. Elsevier; 2012. p.1053. 19. Bates LS, Waldren RP, Teare ID. Rapid determination of free proline for water-stress studies. Plant Soil. 1973;39:205-207. https://doi.org/10.1007/BF00018060 20. Rosenberg , H.R. Chemistry and physiology of vitamins. Inter science Publishers, Inc., New York. 1992. pp. 452- 453. 21. Grieve CM, Grattan SR. Rapid assay for determination of water soluble quaternary ammonium compounds. Plant Soil. 1983;70:303-307. https://doi.org/10.1007/BF02374789. 22. Durner EF. Applied plant science experimental design and statistical analysis using SAS® OnDemand for Academics. CABI; 2021 p.398. 23. El Sherbiny HA, El-Hashash EF, Abou El-Enin MM, Nofal RS, Abd El-Mageed TA, Bleih EM, El- Saadony MT, El-Tarabily KA, Shaaban A. Exogenously applied salicylic acid boosts morpho- physiological traits, yield, and water productivity of lowland rice under normal and deficit irrigation. Agronomy. 2022;12(8):1860. https://doi.org/10.3390/agronomy12081860. 24. Sleibi AT, Abdullah AK. Molecular Signaling and Transcription Factors under Drought Stress and Micronutrient Deficiency in Crop Development: A article Review. J Alharf. 2024. 25. Gupta SD. Reactive oxygen species and antioxidants in higher plants. CRC press; 2010.p.364. 26. Bhargava S, Sawant K. Drought stress adaptation: metabolic adjustment and regulation of gene expression. Plant Breed. 2013;132(1):21-32. https://doi.org/10.1111/pbr.12004. 27. Hashim EK, Hassan SF, Abed BA, Flaih HM. Role of flag leaf in wheat yield. Iraqi J Agric Sci. 2017;48(3):782.-790. https://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/392/310. 28. Saquee FS, Diakite S, Kavhiza NJ, Pakina E, Zargar M. The Efficacy of Micronutrient Fertilizers on the Yield Formulation and Quality of Wheat Grains. Agronomy. 2023; 13(2):566. https://doi.org/10.3390/agronomy13020566. 29. Khatun MT, Mia ML, Talukder¹ SK, Datta P, Das B, Kabir MH, Islam MS. Effect of zinc and iron fertilization on yield of wheat. J Biosci Agric Res. 2014; 32(02): 2649-2659. https://doi.org/10.18801/jbar.320224.319. https://doi.org/10.21123/bsj.2013.10.3.832-843 https://doi.org/10.1016/j.plaphy.2018.01.010 http://dx.doi.org/10.35124/bca.2019.19.2.3495 https://www.iraqoaj.net/iasj/download/9b01ec7668b547ad https://doi.org/10.1007/s42976-021-00226-1 https://doi.org/10.1016/0003-2697(87)90489-1 https://doi.org/10.1016/0003-2697(87)90489-1 https://doi.org/10.1002/jsfa.2740360918 https://doi.org/10.1007/BF00018060 https://doi.org/10.1007/BF02374789 https://doi.org/10.3390/agronomy12081860 https://doi.org/10.1111/pbr.12004 https://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/392/310 https://doi.org/10.3390/agronomy13020566 https://doi.org/10.18801/jbar.320224.319 IHJPAS. 2025, 38 (4) 95 30. Kumari VV, Banerjee P, Verma VC, Sukumaran S, Chandran MAS, Gopinath KA, Venkatesh G, Yadav SK, Singh VK, Awasthi NK. Plant Nutrition: An Effective Way to Alleviate Abiotic Stress in Agricultural Crops. Int J Mol Sci. 2022;23(15):8519. https://doi.org/10.3390/ijms23158519. 31. Waraich EA, Ahmad R, Ashraf MY. Role of mineral nutrition in alleviation of drought stress in plants. Austrl J Crop Sci. 2011; 5(6): 764-777. https://www.cropj.com/waraich_5_6_2011_764_777.pdf. 32. Mannan MA, Tithi MA, Islam MR, Al Mamun MA, Mia S, Rahman MZ, Hossain MS. Soil and foliar applications of zinc sulfate and iron sulfate alleviate the destructive impacts of drought stress in wheat. Cereal Res Commun. 2022; 50(4), 1279-1289. https://doi.org/10.1007/s42976-022- 00262-5 33. Zewdu D, Mekonnen F, Geleta N. Cluster and principal component analysis for yield and yield related traits of bread wheat (Triticum aestivum L.) genotypes. Agric Biol Res. 2024;40(2): 926- 967. https://doi.org/10.35248/0970-1907.24.40.962-967. 34. Hussain MA, Hameed MU, Ahmad N. Principal component analysis in Triticum aestivum under field conditions for food security. J Biol Agric Advanc. 2024;2(1):11-21. https://journalbaa.com/index.php/jbaa/article/view/11. 35. Jawad MM, Al-Shahwany AW, Khudhair SH. Effect of Bio-chemical Fertilizer on Proline Accumulation, Catalase and Peroxidase Enzymes Activity in Leaves of Two Wheat Cultivars (Ipa99 and Rabyaa) Under Water Deficit Stress. Iraqi J Sci. 2015:1350-1358. https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/10100. 36. Mahmoud SN. Evaluation of bread wheat Triticum aestivum L. callus genotypes for water stress tolerance using Polyethylene Glycol (PEG). Baghdad Sci J. 2012;9(3):391-396. https://doi.org/10.21123/bsj.2012.9.3.391-396. 37. Abdelghany M, Makhmer K, Zayed E, Salama Y, Amer K. Genetic variability, principle components and cluster analysis of twenty-eight egyptian wheat genotypes. Scient J Agric Sci. ;5(1):107-18. https://doi.org/10.21608/sjas.2023.179573.1272. 38. Mannan MA, Tithi MA, Islam MR, Al Mamun MA, Mia S, Rahman MZ, Hossain MS. Soil and foliar applications of zinc sulfate and iron sulfate alleviate the destructive impacts of drought stress in wheat. Cereal Res Commun. 2022; 50(4), 1279-1289. https://doi.org/10.1007/s42976-022- 00262-5. 39. Sancenón V, Puig S, Mateu-Andrés I, Dorcey E, Thiele DJ, Peñarrubia L. The Arabidopsis copper transporter COPT1 functions in root elongation and pollen development. J Biol Chem. 2004;279(15):15348-55. https://doi.org/10.1074/jbc.m313321200. 40. Zhang Y, Shi R, Rezaul KM, Zhang F, Zou C. Iron and zinc concentrations in grain and flour of winter wheat as affected by foliar application. J Agric Food Chem. 2010;58(23):12268-74. https://doi.org/10.1021/jf103039k. 41. Hasanuzzaman M, Bhuyan MHMB, Zulfiqar F, Raza A, Mohsin SM, Mahmud JA, Fujita M, Fotopoulos V. Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator. Antioxidants (Basel). 2020;9(8):681. https://pubmed.ncbi.nlm.nih.gov/32751256/. 42. Kim JS, Kidokoro S, Yamaguchi-Shinozaki K, Shinozaki K. Regulatory networks in plant responses to drought and cold stress. Plant Physiology. 2024 May;195(1):170-89. 43. Sun C, Wu T, Zhai L, Li D, Zhang X, Xu X, Ma H, Wang Y, Han Z. Reactive Oxygen Species Function to Mediate the Fe Deficiency Response in an Fe-Efficient Apple Genotype: An Early Response Mechanism for Enhancing Reactive Oxygen Production. Front Plant Sci.;7:1726. https://doi.org/10.3389/fpls.2016.01726. 44. Bapela T, Shimelis H, Tsilo TJ, Mathew I. Genetic Improvement of Wheat for Drought Tolerance: Progress, Challenges and Opportunities. Plants (Basel). 2022;11(10):1331. https://doi.org/10.3390/plants11101331. 45. Zaouali W, Mahmoudi H, Salah IB, Mejri F, Casabianca H, Hosni K, Ouerghi Z. Copper-induced changes in growth, photosynthesis, antioxidative system activities and lipid metabolism of cilantro https://doi.org/10.3390/ijms23158519 https://www.cropj.com/waraich_5_6_2011_764_777.pdf https://doi.org/10.1007/s42976-022-00262-5 https://doi.org/10.1007/s42976-022-00262-5 https://doi.org/10.35248/0970-1907.24.40.962-967 https://journalbaa.com/index.php/jbaa/article/view/11 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/10100 https://doi.org/10.21123/bsj.2012.9.3.391-396 https://doi.org/10.21608/sjas.2023.179573.1272 https://doi.org/10.1007/s42976-022-00262-5 https://doi.org/10.1007/s42976-022-00262-5 https://doi.org/10.1074/jbc.m313321200 https://doi.org/10.1021/jf103039k https://pubmed.ncbi.nlm.nih.gov/32751256/ https://doi.org/10.3389/fpls.2016.01726 https://doi.org/10.3390/plants11101331 IHJPAS. 2025, 38 (4) 96 (Coriandrum sativum L.). Biologia. 2020; 75: 367-380. https://doi.org/10.2478/s11756-020-00419- 9 46. Shafiq S, Akram NA, Ashraf M, García-Caparrós P, Ali OM, Latef AAHA. Influence of Glycine Betaine (Natural and Synthetic) on Growth, Metabolism and Yield Production of Drought-Stressed Maize (Zea mays L.) Plants. Plants (Basel). 2021;10(11):2540. https://pubmed.ncbi.nlm.nih.gov/34834903. 47. Shao HB, Chu LY, Wu G, Zhang JH, Lu ZH, Hu YC. Changes of some anti-oxidative physiological indices under soil water deficits among 10 wheat (Triticum aestivum L.) genotypes at tillering stage. Colloids Surf B: Biointerfaces. 2007;54(2):143-149. https://doi.org/10.1016/j.colsurfb.2006.09.004. 48. Gelaw TA, Sanan-Mishra N. Molecular priming with H9O2 and proline triggers antioxidant enzyme signals in maize seedlings during drought stress. Biochim Biophys Acta Gen Subj. 2024;1868(7):130633. https://doi.org/10.1016/j.bbagen.2024.130633. 49. Hussein MJ, Abdullah AK. Exogenous of silicon and glycine betaine improves salinity tolerance of pepper plants (Capsicum annum L.). Plant Arch. 2019;19:664-672. http://plantarchives.org/SPL%20ISSUE%20SUPP%202,2019/118%20(664-672).pdf. 50. Ashraf MF, Foolad MR. Roles of glycine betaine and proline in improving plant abiotic stress resistance. Environ Exper Bot. 2007;59(2):206-216. https://doi.org/10.1016/j.envexpbot.2005.12.006. 51. Pandey R, Gupta S, Singh S. Role of micronutrients in enhancing antioxidant defense in crops under stress conditions. Plant Physiol Biochem. 2023. 182, pp. 72-81. https://doi.org/10.1007/978- 3-030-45669-6_4. 52. Munné-Bosch S, Alegre L. The function of tocopherols and tocotrienols in plants. Crit Rev Plant Sci. 2002;21(1):31-57. https://doi.org/10.1080/0735-260291044179. 53. Abd SF, Abdullah AK. Interaction effect of silicon and nitric oxide on the activity of enzyme and non-enzyme antioxidants on tomato plant exposed to cadmium stress. Biochem Cell Arch. 2020;20(1). https://doi.org/10.2478/s11756-020-00419-9 https://doi.org/10.2478/s11756-020-00419-9 https://pubmed.ncbi.nlm.nih.gov/34834903 https://doi.org/10.1016/j.colsurfb.2006.09.004 https://doi.org/10.1016/j.bbagen.2024.130633 http://plantarchives.org/SPL%20ISSUE%20SUPP%202,2019/118%20(664-672).pdf http://plantarchives.org/SPL%20ISSUE%20SUPP%202,2019/118%20(664-672).pdf https://doi.org/10.1016/j.envexpbot.2005.12.006 https://doi.org/10.1007/978-3-030-45669-6_4 https://doi.org/10.1007/978-3-030-45669-6_4 https://doi.org/10.1080/0735-260291044179