Evaluation of foliar micronutrients for enhanced seed cotton yield and fibre quality in cotton (Gossypium hirsutum L.)

Introduction

Cotton (Gossypium hirsutum L.) is an important commercial fibre crop and a major contributor to India's agricultural and textile economy. Cottonseed also has considerable value as a source of oil, livestock feed and industrial products. Cotton productivity and fibre quality are influenced by genotype, environment and crop management, with balanced plant nutrition playing an important role. Cotton requires substantial quantities of nutrients throughout its prolonged vegetative and reproductive growth. Although nitrogen, phosphorus and potassium are the major nutrients, micronutrients such as zinc, iron, boron, manganese, copper and molybdenum are essential for photosynthesis, enzyme activity, hormonal regulation, reproductive development and assimilate partitioning. Their deficiency can adversely affect plant growth, boll retention, seed development and fibre production. Foliar application offers an effective supplementary method of supplying micronutrients directly to the crop canopy during critical growth and reproductive stages. Timely foliar nutrition during flowering, boll setting and boll development may improve nutrient availability and influence seed cotton yield and fibre quality. However, the response to foliar micronutrients varies with nutrient formulation, concentration, application timing, genotype and environmental conditions.

Since fibre development involves elongation, secondary cell-wall deposition and maturation, adequate nutrient supply is important for achieving desirable fibre characteristics such as length, strength, micronaire, uniformity and elongation. Therefore, the present investigation was undertaken to evaluate the effect of different foliar micronutrient formulations on growth, reproductive traits, seed cotton yield and fibre quality of cotton.

Materials and Methods

The field experiment was conducted during the kharif, 2025 at the Cotton Research Unit, Dr. PDKV, Akola, Maharashtra, India. The experimental site is situated in the Vidarbha region of Maharashtra at 22°42′ N latitude and 77°02′ E longitude, with an altitude of 307.42 m above mean sea level. Akola experiences a semi-arid tropical climate and receives the major proportion of its annual rainfall during the southwest monsoon. Cotton hybrid 'Ajeet-155' was grown in a Randomized Block Design (RBD) with three replications. The crop was sown at a seed rate of 2.5-3.0 kg ha⁻¹ with a spacing of 90 × 30 cm. The gross plot size was 7.20 × 4.50 m, while the net plot size was 5.40 × 3.90 m. Eight treatments comprising different foliar micronutrient formulations were evaluated viz., T₀: RDF + water spray (Control), T₁: PDKV Micro Grade-XI, T₂: New PDKV Micro Grade-A, T₃: New PDKV Micro Grade-B, T₄: New PDKV Micro Grade-C, T₅: New PDKV Micro Grade-D, T₆: New PDKV Micro Grade-E and T₇: New PDKV Micro Grade-F. All treatments received the recommended dose of fertilizers, and the respective foliar micronutrient formulations were applied as per the treatment schedule.

Five representative plants were selected and tagged from each net plot for recording observations on growth and reproductive attributes. Plant height was recorded at 30, 60, 90 and 120 days after sowing (DAS), while the number of sympodial branches plant⁻¹ was recorded at 60, 90 and 120 DAS. Number of bolls plant⁻¹ and boll weight were recorded following standard field procedures. Seed cotton yield was recorded from successive pickings and expressed as kg plot⁻¹ and q ha⁻¹. Seed index, lint index and harvest index were calculated using standard procedures. Fibre quality parameters, including fibre strength, micronaire, fibre uniformity index and fibre elongation were evaluated. Fibre length, strength, micronaire, uniformity and elongation were determined using a High-Volume Instrument (HVI)

Results and Discussion

Growth and reproductive development Foliar application of micronutrients significantly influenced plant height at 60, 90 and 120 DAS, whereas treatment differences were non-significant at 30 DAS. At 30 DAS, plant height ranged from 27.39 to 31.72 cm, with the highest value under T₆ (31.72 cm) and the lowest under T₀ (27.39 cm). At 60 DAS, T₁ recorded the highest plant height (96.97 cm), while T₆ recorded the highest values at 90 DAS (134.91 cm) and 120 DAS (138.53 cm). The enhanced plant height under T₆ during the later stages may be associated with improved nutrient availability, photosynthetic activity, enzyme activation and cellular growth. Similar favourable effects of foliar micronutrient nutrition on cotton growth have been reported by Radhika et [17, 27] . [17, 27] .

Reproductive traits

The number of bolls plant⁻¹ was significantly affected by treatments at 90 and 120 DAS but not at 60 DAS. At 60 DAS, T₆ recorded the highest number of bolls (4.93 plant⁻¹). At 90 DAS, T₆ recorded the maximum number of bolls (15.25 plant⁻¹), whereas at 120 DAS T₇ recorded the highest number (25.81 plant⁻¹), followed by T₆ (25.17). The control consistently recorded the lowest boll number. Improved boll production under micronutrient treatments may be associated with improved nutritional status and physiological activity during flowering and boll formation. Boll weight was not significantly influenced by foliar micronutrient application. The values ranged from 5.16 to 5.29 g, with the highest value under T₀ (5.29 g) and the lowest under T₂ (5.16 g). The narrow range suggests that individual boll weight was comparatively less responsive to the treatments under the prevailing conditions.

Seed cotton yield and yield components

Seed cotton yield plot⁻¹ was significantly influenced by foliar micronutrient application. Yield ranged from 2.29 to 3.43 kg plot⁻¹. T₆ recorded the highest yield (3.43 kg plot⁻¹), followed by T₇ (3.26 kg), T₅ (2.80 kg) and T₄ (2.57 kg), whereas T₀ recorded the lowest yield (2.29 kg plot⁻¹). The higher yield under T₆ may be attributed to its favourable effects on sympodial branching and boll production, which increased the effective reproductive sink.

On a hectare basis, seed cotton yield ranged from 10.85 to 16.30 q ha⁻¹. T₆ recorded the highest yield (16.30 q ha⁻¹) followed by T₇ (15.50 q ha⁻¹) and T₅ (13.34 q ha⁻¹), while T₀ recorded the lowest yield (10.85 q ha⁻¹). The increase in productivity under T₆ was associated with improved nutrient availability, physiological activity, sympodial branching and boll formation. The present findings support earlier observations of Radhika et al. (2013) and Rajendran et al.

(2019) [17, 27] regarding the beneficial contribution of foliar micronutrient nutrition to cotton productivity. Seed index was significantly influenced by foliar micronutrient application. T₆ recorded the highest seed index (12.75), followed by T₇ (11.05), while the control recorded the lowest value (10.01). The higher seed index under T₆ may be related to improved nutrient availability, assimilate production and translocation towards developing seeds.

Lint index also showed a significant response. T₆ recorded the highest lint index (7.03), followed by T₇ (6.80), while the control recorded the lowest value (5.43). Improved nutrient availability and enhanced assimilate translocation during fibre development may have contributed to the superior response of T₆.

Harvest index was significantly influenced by foliar micronutrient application. T₆ recorded the highest harvest index (43.00%) followed by T₃ and T₇ (41.00% each), while T₀ recorded the lowest value (33.00%). The higher harvest index under T₆ reflects comparatively efficient partitioning of biomass towards economic yield. [17, 27] . Micronaire value was not significantly influenced by the treatments. The highest numerical value was recorded under T₆ (4.40) followed by T₇ (4.26), whereas the control recorded the lowest value (4.00). Similarly, fibre uniformity index was non-significant, although T₆ recorded the highest numerical value (87.66%) compared with 82.33% under the control. Fibre elongation was significantly influenced by foliar micronutrient application. T₆ recorded the highest fibre elongation (13.01%) followed by T₅ (11.27%), while T₀ recorded the lowest value (7.60%). The favourable response under T₆ may be related to improved nutrient availability, enzyme activity, carbohydrate metabolism and cell-wall development during fibre growth.

Fibre quality

Conclusion

The present study revealed that foliar application of micronutrients significantly influenced several important growth, reproductive, yield and fibre-quality attributes of cotton. Among the treatments, New PDKV Micro Grade-E (T₆) exhibited the most favourable and consistent performance. It recorded the highest plant height at 90 and 120 DAS, sympodial branches plant⁻¹ at 60, 90 and 120 DAS, seed cotton yield plot⁻¹ (3.43 kg), seed cotton yield (16.30 q ha⁻¹), seed index (12.75), lint index (7.03) and harvest index (43.00%). It also produced the highest fibre strength (31.40 g tex⁻¹) and fibre elongation (13.01%). New PDKV Micro Grade-E (T₆) additionally recorded the highest numerical values for micronaire and fibre uniformity index although these traits were statistically non-significant. Thus, New PDKV Micro Grade-E emerged as the most promising foliar micronutrient treatment for enhancing seed cotton productivity and some fibre-quality attributes of cotton.

Acknowledgement

AcknowledgementThe authors gratefully acknowledge the Cotton Research Unit, Dr. PDKV, Akola for providing field facilities and technical support during the kharif, 2025. The authors also acknowledge the AICRP on Micronutrients, Department of Soil Science and AICRP on PHET, College of Agricultural Engineering, Dr. PDKV, Akola for laboratory facilities and technical assistance during the investigation.

References

1. Abbas A, et al. Foliar application of silicon and boron improves boll retention, lint yield and fiber quality traits of transgenic cotton. Journal of King Saud UniversityScience. 2023;35(8):102858.
2. Abdallah AM, Mohamed HFY. Effect of foliar application of some micronutrients and growth regulators on some Egyptian cotton cultivars. Journal of Applied Sciences Research. 2013;9(6):3497-3507.
3. Abdel-Tawab RM, El-Ssadi SA. Response of two Egyptian cotton cultivars to the balanced fertilization between macro and micro nutrients as foliar application. Journal of Plant Production. 2020;11(12):1539-1551.
4. Ahmad S, Akhtar LH, Iqbal N, Nasim M. Cotton (Gossypium hirsutum L.) varieties responded differently to foliar applied boron in terms of quality and yield. Soil and Environment. 2009;28:88-92.
5. Ahmed N, Abid M, Rashid A, Ali MA, Amanullah M. Boron requirement of irrigated cotton in a Typic Haplocambid for optimum productivity and seed composition. Communications in Soil Science and Plant Analysis. 2013;44:1293-1309.
6. Ali L, Ali M, Mohyuddin Q. Effect of foliar application of zinc and boron on seed cotton yield and economics in cotton-wheat cropping pattern. Journal of Agricultural Research. 2011;49(2):173-180.
7. Alloway BJ. Zinc in soils and crop nutrition. 2nd ed. Brussels, Belgium and Paris, France: International Zinc Association and International Fertilizer Industry Association; 2008.
8. Amutha R, Shivkumar T, Ananth Kumar CC. Foliar nutrition to reduce the shedding and square drain in cotton (Gossypium hirsutum L.). In: National Symposium on Bt Cotton Opportunities and Prospects; Nagpur, India; 2009. p. 64.
9. Cakmak I, Yazici AM. Magnesium: A forgotten element in crop production. Better Crops. 2010;94(2):23-25.
10. De Souza Júnior JP, de Mello Prado R, Campos CNS, Oliveira DF, Cazetta JO, Detoni JA. Silicon foliar spraying in the reproductive stage of cotton plays an equivalent role to boron in increasing yield, and combined boron-silicon application, without polymerization, increases fiber quality. Industrial Crops and Products. 2022;182:114888.
11. Eleyan SED, Abodahab AA, Abdallah AM, Raheb HA. Foliar application of boron and zinc effects on growth, yield and fiber properties of some Egyptian cotton cultivars (Gossypium barbadense L.). International Journal of Agriculture and Crop Sciences. 2014;7(13):1274-1282.
12. Fageria NK, Baligar VC, Clark RB. Micronutrients in crop production. Advances in Agronomy. 2002;77:185268.
13. Kaur P, Buttar GS, Kaur M, Gill MS, Sohu RS. Effect of foliar and split application of potassium on seed cotton yield and fibre quality of American cotton (Gossypium hirsutum). Indian Journal of Agricultural Sciences. 2011;81(9):838-842.
14. Rajendran K, Palchamy A, Sankaranarayanan K, Prabakaran K, Bhararhi K. Enhancing productivity of summer irrigated cotton through plant growth regulator and foliar nutrition. Madras Agricultural Journal. 2011;98(7-9):248-250.
15. Rajendran K, Amanullah MM, Vaiyapuri K. Foliar nutrition in cotton A review. Agricultural Reviews. 2010;31(2):120-126.
16. Rajput LB, Gilal AA, Abro GH, Mastoi MI, Sahito JGM, Nizamani IA. Effect of application of micronutrients on the lint quality parameters of cotton. Science International (Lahore). 2016;28(2):1295-1298.
17. Radhika K, Hemalatha S, Katharine SP, Maragatham S, Kanimozhi A. Foliar application of micronutrients in cotton A review. Research and Reviews: Journal of Agriculture and Allied Sciences. 2013;2(3):23-29.
18. Ramesh K, Chandrasekharan B. Responses of cotton to zinc A review. Agricultural Reviews. 2000;21(4):278280.
19. Sankaranarayanan K, Praharaj CS, Nalayini P, Bandyopadhyay KK, Gopalakrishnan N. Effect of magnesium, zinc, iron and boron application on yield and quality of cotton (Gossypium hirsutum). Indian Journal of Agricultural Sciences. 2010;80(8):699-703.
20. Sawan ZM, Hafez SA, Basyony AE, Alkassas AR. Cottonseed: protein, oil yields, and oil properties as influenced by potassium fertilization and foliar application of zinc and phosphorus. Grasas y Aceites. 2007;58(1):40-48.
21. Shukla AK, Behera SK, Shivay YS, Singh P, Singh AK. Micronutrients and field crop production in India: A review. Indian Journal of Agronomy. 2012;57(3s):123-130.
22. Silva RA, Santos JL, Oliveira LS, Soares MRS, dos Santos SMS. Biostimulants on mineral nutrition and fiber quality of cotton crop. Revista Brasileira de Engenharia Agrícola e Ambiental. 2016;20(12):10621066.
23. Xu HJ, Yang XJ, Zhu YX. Research on the role of micronutrient management in improving cotton fiber quality. Cotton Genomics and Genetics. 2025;16(2):7279.
24. Yaseen M, Ahmed W, Shahbaz M. Role of foliar feeding of micronutrients in yield maximization of cotton in Punjab. Turkish Journal of Agriculture and Forestry. 2013;37(4):420-426.
25. Yin X, Gwathmey O, Main C, Johnson A. Effects of sulfur application rates and foliar zinc fertilization on cotton lint yields and qualities. Agronomy Journal. 2011;103(6):1794-1803.
26. Yogesh GS, Prakash SS, Thimmegowda MN. Effect of micronutrients application under different fertilizer prescription methods on growth and yield of Bt cotton. International Journal of Plant & Soil Science. 2022;34(20):558-564.
27. Rajendran R, Kunjusankaran RN, Sandhya R, Anilkumar A, Santhosh R, Patil SR. Comparative evaluation of remineralizing potential of a paste containing bioactive glass and a topical cream containing casein phosphopeptide-amorphous calcium phosphate: An in vitro study. Pesquisa brasileira em odontopediatria e clinica integrada. 2019;19:e4668.