Micronutrient-based plant growth promotion for enhancing yield and profitability of wheat varieties in the Indo-Gangetic plains

Introduction

Wheat is a major winter cereal in the Indo-Gangetic Plains of South Asia and is crucial to food security in this region. It is a substantial contributor to calorie and protein intake. With December 2024 announcement, third advance estimates for 2024-25 (Department of Agriculture and Farmers Welfare 2025) [3] for wheat output stood at 1175.07 lakh tonnes. India's wheat production pays due attention. The intensively cultivated wheat systems are increasingly getting constrained for productivity improvement due to soil nutrients imbalance, heat and moisture stress during terminal stages, falling factor productivity and rising input costs. To meet these challenges, nutrient management strategies that enhance both biological efficiency and economic return rather than sole dependence on increased macronutrient inputs are necessary. Micronutrients are required in small quantities, but exhibit large functional role in wheat. Zinc, iron, copper, and boron serve essential functions in chlorophyll biosynthesis, enzyme activation, the functioning of pollen, the metabolism of carbohydrates, and cell-wall formation and filling of the grain. The restricted tillering and dry matter accumulation and spike fertility and grain weight found when nitrogen, phosphorus and potassium are applied in recommended doses may be linked to deficiency of these elements. Wheat studies have revealed that iron and zinc application can enhance yield attributes, grain yield and benefit-cost ratio (Choudhary et al. 2021) [2] while foliar zinc application has also been shown to enhance grain zinc concentration and bioavailability in wheat cultivars and landraces (Hao et al. 2021) [6] . Farmers are also using growth promoters such as gibberellic acid, seaweed extract, humic and fulvic acids, amino acid formulations and fermented nutrient extracts. The physiological processes may be changed, photosynthate transport enhanced, stress injury delayed, root growth improved and nutrient uptake increased. Seaweed-based inputs have received attention as a biostimulant for plant development. The reason for this is that seaweed contains mineral nutrients, organic compounds and hormone-like substances (El Boukhari et al. 2020) [4] . In this regard, twoseason wheat experiments linked seaweed and microbial consortia with improved physiological status and yield under water-limited environments. (Vafa et al. 2022; Vafa et al. 2024) [12, 13] . The varietal responses of a micronutrient mixture need to be evaluated against other plant growth promoters conducted under the same field condition with yield and profitability analysed together. The present study therefore re-analysed the comparative effect of a Zn-Fe-Cu-B micronutrient mixture and other growth promotors on growth, yield attributes, yield, harvest index and economics of DBW-187 and PBW-723 wheat varieties under the conditions of central Indo-Gangetic Plain of Uttar Pradesh.

Materials and Methods

The experiment was conducted in Rabi 2022-23 at the Students' Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology (CSAUAT) Kanpur, Uttar Pradesh, India. The experimental farm is located at an elevation of 125.9 m above the mean sea level in the Indo-Gangetic alluvial tract of central Uttar Pradesh at about lat. 26°29′35″ N and long. 80°16′25″ E. The location has a semi-arid subtropical climate. Throughout the growing season, the temperature ranged from cool winter conditions to high temperatures in April and the rainfall during the growing season was low and there was thus supply of irrigation at critical stages. Originally, the soil of the experimental field was sandy-loam in texture, slightly alkaline in reaction and low in available nitrogen. The organic carbon, available nitrogen, available phosphorus, available potassium and pH of the soil was found to be 0.48%, 148.20 kg/ha, 20.60 kg/ha, 215.50 kg/ha and 7.7, respectively. The trial was set up in a split-plot design and replicated three times. The main plots had wheat varieties and the sub-plots had plant growth promoter treatments. The gross plot size of the experiment was 5 m × 4 m, net plot size was 4 m × 3 m and spacing was 20 cm × 10 cm. The sowing of wheat took place on 5 December 2022. Moreover, and the recommended fertilizer dose of wheat crop was 120:60:40 kg N:P 2 O 5 :K 2 O/ha. The main plot factor included two varieties of wheat: DBW-187 and PBW-723. The nine treatments that were classified under the sub-plot TGP factor were control; nitrobenzene @ 3 ml/L; gibberellic acid (GA3) @ 2000 ppm; solid seaweed extract (SWE) @ 25 kg/ha; liquid SWE @ 625 ml/ha; micronutrient mixture comprising of Zn, Fe, Cu and B @ 0.5% (MI); UPL Macarena fermented nutrient extract @ 625 ml/ha; Humesol containing humic acid and fulvic acid @ 1250 ml/ha, and Amino Booster G containing 30% amino acid solution @ 5 ml/L. The cultural practices were standard and uniformly followed. Watering was done before seeding and at four critical stages on December 26, 2022, January 20, 2023, February 14, 2023 and March 11, 2023. Weeds were controlled with clodinafoppropargyl and metsulfuron methyl at 30-35 DAS. The crop matured on 11 April 2023 and harvested on 21 April 2023. Data collection in the research, investigation was carried out for growth observations of plant population, plant height, tillers/m2, fresh weight, dry weight and crop growth rate. The plant height was measured at 45 days after sowing (DAS), 90 DAS and at maturity. The 1 m x 1 m quadrate was used for counting the tillers that are expressed as tillers/m2. The fresh and dry weights per plant were recorded at 45 DAS, 90 DAS and maturity. The recording of crop growth rate was done for 0-45 DAS, 45-90 DAS and 90 DAS to harvest. The attributes that were utilized to measure the performance of an ear are as follows: number of ears/m2, ear length, number of seeds/ear, seed weight/ear and test weight. The measurement of grain and straw yield from each plot was done in kilograms per hectare. The total between the straw and the grain taken together. The calculation of harvest index is a percentage ratio of the grain yield to biological yield. The costs to the government are analyzed through the benefit-cost ratio in the economic analysis. Estimation of Gross Return and Benefit-Cost Ratio Gross returns were calculated based on prices prevailing during the study period, net returns were calculated by deducting cost of cultivation from gross returns and benefit-cost ratio was calculated by dividing gross return by cost of cultivation. The data contained fresh weight, dry weight as well as harvest index. Relative growth rate and absolute growth rate were computed as derived indices using mean dry-weight data. The AGR and RGR are interpreted as secondary physiological measure rather than independently tested primary endpoints.

Equations utilized for derived quantities

 Biological yield is the weight of total biomass produced per unit land together with the harvestable yield of a crop.  The Harvest index is defined as the ratio of grain yield to biological yield; the gross return is the sum of the value of grain yield and straw yield.  The formula for computing net return is gross return less cost of cultivation.  Benefit-cost ratio equals gross return, divided by cost of cultivation.  The formula used for calculating the absolute growth rate is W2 -W1 / T 2 -T 1 .  The relative growth rate is calculated as the product of the change in natural logarithm over a time interval by 1/t.  Crop growth rate, expressed in g/m2/day, refers to the increase in dry matter occurring per unit land area per unit time.

In the AGR and RGR formulae, W1 and W2 stand for dry weight at two consecutive observations and T 1 and T 2 stand for the corresponding dates. The AGR and RGR are calculated for 45-90 DAS and 90 DAS-maturity intervals. Analysis of variance for a split-plot design was used to assess the original experiment, which used variety as the main-plot factor and plant growth promoter as the sub-plot factor. The relevant error terms were used to estimate the main effects of the variety, the main effects of the plant growth promoters and the variety × growth promoter interactions. Mean comparisons were interpreted according to the critical difference at 5% probability. [2] stated that iron and zinc had similar positive effects on the growth and economic yield of wheat. Further, micronutrient application through foliage was found to be essential for the improvement of grain minerals according to Hao et al. (2021) [6] . [8,13] .

Physiological indices that were derived

Physiological efficiency and harvest index

DBW-187 had a harvest index of 39.50% whereas PBW-723 recorded 38.30%. The micronutrient mixture possessed the highest harvest index (39.87%) among plant growth promoters, gibberellic acid (39.65%), seaweed liquid (39.48%) and seaweed solid (39.37%). Only 35.82% of the control was recorded. Improvements in harvest index under micronutrients indicate that the yield increase was not merely due to the accumulation of vegetative biomass; a greater portion of biological yield was partitioned into the grain. The enhanced harvest index may be due to the impact of boron on reproductive development, zinc on enzyme and auxin metabolism, iron on chlorophyll-linked electron transport and copper on oxidative enzyme systems. These processes all enhance the movement from source to sink during the development of grain. Nonetheless, the validation of harvest index values over subsequent years is essential, as terminal weather has a profound impact on wheat grain filling. [2] , bolstering wheat's yield profitability is associated with micronutrient fertilization.

Profitability and feasibility in economics

The effects of wheat varieties and nutrient management

The main-effect pattern allows us to make a pragmatic inference that DBW-187 was the superior variety while the micronutrient mixture was the best growth promoter. Thus, the joint recommendation should be regarded as encouraging.

Interpreting correlation and regression

The association of yield with maturity plant height (r= 0996), harvest index (r= 0995), net return (r= 0993), dry weight at maturity (r= 0.979) and CGR during 45-90 DA (r= 0.977) was found to be very strong in exploratory correlation based on treatment means. Evaluating Treatments in the Context of the Agronomic Response Gradient.

The test weight alone explained a large portion of the treatmentmean variation in grain yield (R2=0.986). The dry weight at maturity (R2=0.958) and the CGR between 45 and 90 DAS (R2=0.954) were other good predictors. The regression model relies on nine treatment means, meaning the aforementioned results should not be taken as causal proof. The biological explanation is that improving grain yield enabled better biomass accumulation, spike development and grain filling that supported the pattern.

Conclusion

DBW-187 was found to be a better wheat variety and Zn-Fe-Cu-B micronutrient mixture was discovered to be the best plant growth promoter under one season field conditions of central Uttar Pradesh. According to the results, the treatment of micronutrients with wheat gave the highest grain yield, straw yield, harvest index, net return and benefit-cost ratio. The treatment may be recommended for timely sown wheat as a promising option provided finding is validated over more season and places before the advisory use at large scale.

Disclaimer (artificial intelligence)

Author(s) hereby declare that NO generative AI technologies such as Large Language Models (ChatGPT, COPILOT, etc) and text-to-image generators have been used during writing or editing of manuscripts.

Competing interests

Authors have declared that no competing interests exist.

References

1. Alsudays IM, Abbas MHH, Al-Sayed HM, El-Metwally IM, Ueda A, Seleiman MF. Applications of humic and fulvic acid under saline soil conditions to improve growth and yield in barley. BMC Plant Biol. 2024;24:191. doi:10.1186/s12870-024-04863-6.
2. Choudhary B, Sharma PK, Mandeewal RL, Verma BL, Dudwal M. Response of iron and zinc on yield attributes, yield and economics of wheat (Triticum aestivum L.). Int J Plant Soil Sci. 2021;33(16):29-35. doi:10.9734/ijpss/2021/v33i1630520.
3. Department of Agriculture and Farmers Welfare. Third advance estimates of production of major agricultural crops for 2024-25. New Delhi: Ministry of Agriculture and Farmers Welfare, Government of India; 2025.
4. El Boukhari MEM, Barakate M, Bouhia Y, Lyamlouli K. Trends in seaweed extract-based biostimulants: manufacturing process and beneficial effect on soil-plant systems. Plants. 2020;9(3):359. doi:10.3390/plants9030359.
5. Food and Agriculture Organization of the United Nations. Cereal supply and demand brief. Rome: FAO; 2025.
6. Hao B, Ma J, Jiang L, Wang X, Bai Y, Zhou C, et al. Effects of foliar application of micronutrients on concentration and bioavailability of zinc and iron in wheat landraces and cultivars. Sci Rep. 2021;11:22782. doi:10.1038/s41598-021-02088-3.
7. Indian Journal of Agricultural Sciences. Submissions and author guidelines. New Delhi: Indian Council of Agricultural Research; 2026.
8. Kewat PR, Singh R, Kaifee M, Sanodiya LK. Growth and yield of wheat (Triticum aestivum L.) as affected by biofertilizer and seaweed extract. Int J Environ Clim Change. 2022;12(10):823-829. doi:10.9734/ijecc/2022/v12i1030869.
9. Rathinapriya P, Satish L, Pandian S, Rameshkumar R, Balasangeetha M, Rakkammal K, et al. Effects of liquid seaweed extracts in improving the agronomic performance of foxtail millet. J Plant Nutr. 2020;43(19):2857-2875. doi:10.1080/01904167.2020.1799002.
10. Saxena P, Verma VK, Siddiqui MZ, Singh T, Siddiqui A, Patel A. Assessment of plant growth promoters on growth characteristics, yield attributes and yield of wheat (Triticum aestivum L.) varieties in central plain zone of Uttar Pradesh, India. Int J Plant Soil Sci. 2024;36(8):1093-1100. doi:10.9734/ijpss/2024/v36i84942.
11. Saxena P. Effect of organic and inorganic plant growth promoters on performance of wheat varieties (Triticum aestivum L.). Kanpur (Uttar Pradesh): Chandra Shekhar Azad University of Agriculture and Technology; 2024.
12. Vafa ZN, Sohrabi Y, Ghader Mirzaghaderi GM, Heidari G. Soil microorganisms and seaweed application with supplementary irrigation improved physiological traits and yield of two dryland wheat cultivars. Front Plant Sci. 2022;13:855090. doi:10.3389/fpls.2022.855090.
13. Vafa ZN, Sohrabi Y, Mirzaghaderi G, Heidari G, Rizwan M, Sayyed RZ. Effect of biofertilizers and seaweed extract on wheat under different irrigation regimes. Chemosphere. 2024;364:143068. doi:10.1016/j.chemosphere.2024.143068.