Effect of foliar spray of zinc sulphate and salicylic acid on morpho-physiological and biochemical traits of wheat (Triticum aestivum L.)

Introduction

Wheat (Wheat) is one of the most important cereal crops in the world and serves as a major source of food for millions of people. Belonging to the Poaceae family, wheat is widely cultivated under diverse climatic conditions and plays a vital role in ensuring global food security. Major wheat-producing countries include China, India, United States, Russia, France, and Australia. Due to its extensive cultivation, high adaptability, and productivity, wheat is popularly known as the "King of Cereals." It is mainly grown during the Rabi season and contributes significantly to the global grain trade and nutritional security Food and Agriculture Organization (2023) [5] . In India, wheat cultivation is dominated by three species, namely Triticum aestivum, Triticum durum, and Triticum dicoccum. Among these, Triticum aestivum occupies the largest share of cultivated area and is primarily grown in the northwestern plains of the country. It is rich in gluten protein and is commonly used for preparing bread, biscuits, cakes, and chapatti. Triticum durum is cultivated mainly under rainfed conditions in central and southern India and is preferred for the preparation of pasta, semolina, and vermicelli due to its hard grain texture and high protein content. Triticum dicoccum is cultivated on a limited scale in certain southern and western states and is traditionally used in local food preparations Belderok, et al. (2000) [3] . Globally, wheat occupies a vast cultivated area with high production and productivity levels. In India, wheat is one of the major staple food crops and contributes significantly to agricultural income and national food reserves. Wheat grains are highly nutritious and contain carbohydrates, proteins, vitamins, minerals, and dietary fiber. The grain generally contains 60-80% carbohydrates, mainly in the form of starch, along with 8-15% protein. It also provides small quantities of fat, B-complex vitamins, vitamin E, and crude fiber. Besides human consumption, wheat straw is extensively used as fodder for livestock. Micronutrients and plant growth regulators play an essential role in enhancing wheat growth, productivity, and stress tolerance. Zinc is an important micronutrient required in small quantities for normal plant growth and development. It regulates the synthesis of chlorophyll, carbohydrates, and growth hormones such as indole acetic acid. Zinc application improves photosynthetic activity, nutrient uptake, and grain quality. Foliar application of zinc has been reported to be more effective than soil application because it enhances nutrient absorption and reduces nutrient fixation in soil Nandy et al. (2022) [7] . Salicylic acid is another important plant growth regulator known for its beneficial effects on plant physiology and stress management. Foliar application of salicylic acid improves seed germination, photosynthesis, nutrient translocation, biomass production, and yield attributes in wheat. It also enhances antioxidant enzyme activities, helping plants tolerate drought, salinity, and other abiotic stresses. Salicylic acid acts as a signaling molecule that strengthens plant defense mechanisms and improves overall plant performance under unfavorable environmental conditions. Therefore, the combined use of zinc sulphate and salicylic acid through foliar spray can significantly improve growth, physiological efficiency, and yield of wheat crop under varying environmental conditions Azmat et al. (2020) [2] .

Materials and Methods

The field experiment entitled "Foliar Spray of Zinc Sulphate and Salicylic Acid on Morpho-Physiological, Biochemical and Yield Attributes of Wheat (Triticum aestivum L.)" was conducted during the Rabi season of 2025-26 at the research farm of the Department of Agronomy, Faculty of Agricultural Sciences and Allied Industries, Rama University. The experiment was performed under normal field conditions to evaluate the effect of foliar treatments on wheat growth and productivity. The experimental site is located in the central-western region of Uttar Pradesh at geographical coordinates 26.449923°N latitude and 80.331874°E longitude, with an elevation of about 567 meters above mean sea level.

Results and Discussion

The observations indicated that foliar application of zinc sulphate (ZnSO₄) and salicylic acid (SA) significantly influenced plant height of wheat at various growth stages. Plant height increased continuously from 30 DAS up to harvesting under all treatments. Among the different treatments, salicylic acid at 200 ppm (T7) consistently recorded the maximum plant height at all stages, while the control treatment (T1) showed the minimum values. At 30 DAS, T7 produced the tallest plants, followed by T4 and T6. Similar trends were observed at 60, 90, and 120 DAS as well as at harvest stage. The improvement in plant height due to salicylic acid and zinc application may be attributed to enhanced physiological and biochemical activities within the plant system. Salicylic acid likely promoted cell elongation, photosynthetic efficiency, and stress tolerance, resulting in better vegetative growth. Zinc, being an essential micronutrient, plays an important role in chlorophyll synthesis, enzyme activation, and auxin production, which collectively enhance plant development. The combined effect of these treatments improved nutrient uptake and metabolic processes, leading to vigorous crop growth. Statistical analysis confirmed that treatment differences were significant at the 5% level of significance Alloway, B.J. et al.( 2008) [1] .

The data showed that foliar application of zinc sulphate and salicylic acid significantly enhanced total dry biomass production in wheat at different growth stages. Dry biomass increased progressively from 30 DAS to physiological maturity under all treatments. Among the treatments, T₇ (Salicylic acid @ 200 ppm) recorded the highest dry biomass at all stages, whereas the control treatment (T₁) showed the lowest values. At 30 DAS, maximum dry biomass (2.86 g plant⁻¹) was observed under T₇ compared to 1.85 g plant⁻¹ in the control. Similar trends were recorded at 60, 90, 120 DAS and at maturity. Enhanced dry matter accumulation under salicylic acid and zinc sulphate treatments may be attributed to improved nutrient uptake, increased chlorophyll content, enhanced photosynthetic efficiency, and better translocation of assimilates. Zinc sulphate treatments also improved biomass production over control, with T₄ (ZnSO₄ @ 200 ppm) showing comparatively higher values among zinc treatments.

The data presented revealed that foliar application of zinc sulphate and salicylic acid significantly influenced carotenoids content in wheat at different growth stages. Carotenoids content increased progressively from 20 DAS to 60 DAS and declined slightly at later stages due to crop maturity. Among all treatments, T₇ (Salicylic acid @ 200 ppm) recorded the highest carotenoids content at all growth stages, followed by T₆ and T₄. At 20 DAS, T₇ recorded maximum carotenoids content (0.92 mg g⁻¹ fresh weight), while the control treatment showed the minimum value (0.66 mg g⁻¹). Similar trends were observed at 40, 60, and 80 DAS. Higher carotenoids content under salicylic acid and zinc sulphate treatments may be attributed to enhanced chlorophyll protection, improved photosynthetic activity, and reduced oxidative damage in plant tissues. Treated plants maintained comparatively higher pigment concentration even at harvesting stage, indicating better physiological efficiency and delayed senescence.

Conclusion

The present investigation demonstrated that foliar application of zinc sulphate and salicylic acid significantly improved the morpho-physiological and biochemical traits of wheat under the agro-climatic conditions of Kanpur, Uttar Pradesh. Among the different treatments, salicylic acid at 200 ppm (T₇) proved most effective in enhancing plant height, dry biomass accumulation, and carotenoids content at different growth stages. The improvement in growth and biochemical parameters may be attributed to enhanced nutrient uptake, better photosynthetic activity, increased chlorophyll protection, and improved metabolic processes within the plant system. Zinc sulphate treatments also showed positive effects on crop growth and physiological efficiency compared to the control treatment. Higher carotenoids content and biomass accumulation under foliar treatments indicated improved photosynthetic efficiency and delayed senescence in wheat plants. Therefore, foliar application of salicylic acid at 200 ppm may be considered an effective and economical approach for improving growth, physiological performance, and overall crop productivity of wheat.

References

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