Effect of boron, calcium and zinc on growth, yield and quality of Tomato (Solanum lycopersicum L.)

Introduction

Tomato (Solanum lycopersicum) is one of the most popular and economically important and widely used vegetable crops. Tomatoes belong to the family Solanaceae and have a chromosome number of 2n=2x=24. 'Tomato' might be originated from the Nahautl word "tomatl" meaning "the swelling fruit" and first mentioned in writing in 1595. It was cultivated by Aztices and Incas in the early 700 AD (Roberts, 2014) [1] . Tomatoes are ranked second after potatoes and sweet potatoes in respect to vegetable production in the world and occupy a prominent position in both fresh market consumption and processing industries. The total global area under tomato cultivation is approximately 5.1 million hectares, and the global tomato production is about 192 million MT, with a productivity of about 37-46 MT/ha. The top five major tomato-producing countries in the world are China, India, Turkey, the United States, and Egypt (FAO, 2025) [2] . In India, tomatoes are a major vegetable crop, constituting nearly 7-10% of India's total vegetable area. The area under tomato cultivation in India is about 841,000 to 865,000 ha with a total production of about 21.32 million MT annually (National Horticulture Board, 2024). [3] . The average productivity of tomatoes in the country is cited as approximately 24.96 MT/ha in major producing areas, with some high-performing states even exceeding this limit. The major tomato producing states include Andhra Pradesh, Madhya Pradesh, Karnataka, Tamil Nadu, Odisha, Gujarat, etc. In Uttar Pradesh, major tomato-producing districts include Sonbhadra, Varanasi, Kanpur, Agra, Bareilly, Lucknow, Aligarh, Kannauj, etc. The area under tomato cultivation in U.P is about 25,470 ha with a total production of about 84400 MT annually. The average productivity of tomatoes in the state is about 20 to 25 MT/ha. Tomatoes are considered an important protective food because of their richness in essential nutrients and bioactive compounds. In addition to its economic importance, tomato has been proven to be beneficial to human health, because of its content of phytochemicals such as lycopene, vitamin C, β-carotene, flavonoids, and many essential nutrients (Beutner, 2001) [4] . Micronutrients are essential for plant growth, development, and metabolism. Among the micronutrients, boron, calcium, and zinc play important roles in improving the yield and quality of tomatoes in addition to preventing various diseases and physiological disorders. Zinc is an important micronutrient, a cofactor for numerous enzymes, and influences protein synthesis, carbohydrate metabolism, phosphorus metabolism, sulfur and nitrogen metabolism, sexual fertilization of plants, gene expression, structural and functional integrity of bio-membranes, photosynthetic metabolism, and growth regulation. Boron plays an essential role in cell division, cell elongation, formation of cell walls, formation of vascular bundles, protein and nucleic acid synthesis, synthesis of pectin, maintaining correct water relations within the plant, re-synthesis of adenosine triphosphate (ATP), and translocation of sugar at the development of the flowering and fruiting stages (Bose and Tripathi,1996) [5] . In tomatoes, boron deficiency affects the synthesis of amino acids and proteins. Calcium plays a crucial role in the growth and development of tomato plants, from vegetative to flowering, fruiting, harvesting and post harvest stages. Calcium is a divalent cation (Ca 2+ ) required for structural roles in the cell wall, as a counter-cation for inorganic and organic anions in the vacuole, and as an intracellular messenger in the cytosol (Marschner, 1996) [6] . Calcium deficiency causes abnormal metabolism in tomato plants. This leads to low lycopene content, poor sugar-acid/TSSacidity balance, and thus poor flavor and nutrition of the fruits. Therefore, it is essential to give these nutrients to tomato plants in balanced doses for higher growth, fruit yield and better fruit quality. Considering these points, the present research work on "Effect of Boron, Calcium, and Zinc on Growth, Yield, and Quality of Tomato (Solanum lycopersicum)" was conducted to optimize different combinations of these nutrients on growth, yield and quality of tomato using variety Azad T-6.

Materials and Methods

The field experiment was conducted at the research farm of department of vegetable science at Chandra Shekhar Azad University of Agriculture & Technology, Kanpur, U.P., during rabi season from September 2025 to March 2026. Geographically, Kanpur is located in the Gangetic plains of Central U.P. It lies at 25.28° to 28.50° N latitude range and 79.31° to 84.34° E longitude range at an elevation of 125.90 m above the sea level belonging to the Agro-ecological Zone "AEZVIII" of Central Plain Zone. The climate of the experimental site is subtropical. The maximum temperature ranges from 24° to 46 °C, and the minimum temperature ranges from 6.0° to 24 °C, with relative humidity from 32% to 99% in different months of the year. The average annual rainfall is about 800-850 mm.

The experiment was laid out in a Randomized Block Design (RBD), with eight treatments and three replications. Treatment combinations were: T 1 = Control (B 0% + Zn 0% + Ca 0%) , T 2 = B 0.2% , T 3 = Ca 0.5% , T 4 = Zn 0.5% , T 5 = B 0.2% + Ca .0.5% , T 6 = B 0.2% + Zn 0.5% , T 7 = Ca .0.5% + Zn 0.5% , T 8 = B 0.2% + Ca .0.5% + Zn 0.5% . The plant materials were obtained from the Department of Vegetable Science (Vegetable Research Station, Kalyanpur), Chandra Shekhar Azad University of Agriculture and Technology, Kanpur (Uttar Pradesh) and seedlings were made ready under nursery and were ready for transplanting at 4 to 6 leaf stage. The transplanting was done at a spacing of 60×45 cm 2 . The plants were under regular monitoring with timely irrigation, weeding and recommended dose of fertilizer (NPK) application. Different treatment combinations were applied as foliar spray starting from 30 days after transplanting. A total of three sprays were given at 20, 50 and 80 days after transplanting (DAT). The observations were made regularly on growth, yield and quality characters of fruits. The observations on plant height, number of branches were recorded at 30, 60 and 90 DAT. Total number of flower clusters per plant, flowers per cluster, fruits per cluster, fruits per plant, diameter of fruit, individual fruit weight, yield per plant, yield per plot, yield per hectare, etc. were also counted. The fruit quality in terms of characters like T.S.S., shelf life and acidity% were also determined. The data was statistically analyzed following the methods as stated by Fisher's & Yates with analysis of variance at 5% level of significance.

Results and Discussion

The main findings of the study are summarized below:

Plant height is one of the important parameter which is positively correlated with the yield of tomato. At 30 DAT, highest plant height 39.84 cm was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B), which was at par with T 6 (38.14 cm) and least plant height 24.85 cm was recorded in T 1 (Control). At 60 DAT, significantly higher plant height (63.38 cm) was recorded in T 8, followed by T 6 (59.93 cm) and lowest plant height was recorded in T 1 (44.67 cm). At 90 DAT, significantly higher plant height (105.3 cm) was recorded in T 8 followed by T 6 (98.33cm) and T 5 (94.21cm), and lowest plant height (73.66 cm) was recorded in T 1 (Control). These results are in close agreement with researches of (Davis et al, 2003) [7] , (Mondal and Ghosh, 2023) [8] etc.

Number of primary and secondary branches per plant

To measure the growth rate, the number of primary and secondary branches per plant was counted at 30, 60, and 90 DAT. At 30 DAT, highest number of branches (7.46) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B) and least number of branches (2.46) was recorded in T 1 (Control). At 60 DAT, significantly higher number of branches (32.63) was recorded in T 8 followed by T 6 (28.53) and lowest number of branches (17.40) was recorded in T 1 (Control). At 90 DAT, significantly higher number of branches (35.56) was recorded in T 8 and lowest number of branches (17.73) was recorded in T 1 (Control). The result corroborated with the finding of (Mondal and Ghosh, 2023) [8] . (2.13). These results are in close agreement with researches of (Rab and Haq, 2012) [9] , (Shnain et al., 2014) [10] , (Ali et al., 2015) [11] , etc.

Number of flowers per cluster

Number of flowers per cluster is one of the important parameter which is positively correlated with the yield of tomato. At 40 DAT, highest number of flowers per cluster (6.13) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B), which was at par with T 6 (5.93) (0.5% Zn + 0.2% B), and least number of flowers per cluster (1.73) was recorded in T 1 . At 70 DAT, significantly higher number of flowers per cluster (6.63) was recorded in T 8, which was at par with T 6 (6.56) and lowest number of flowers per cluster was recorded in T 1 (2.40). At 100 DAT, significantly higher number of flowers per cluster (6.53) was recorded in T 8 and lowest number of flowers per cluster was recorded in T 1 (2.00). Number of flowers per cluster increased significantly with B and Zn combination, because boron regulates water absorption and carbohydrate metabolism (Haque et al., 2011) [12] . Thus it is likely that higher number of flowers per cluster could be produced due to sufficient levels of carbohydrates available for flower formation (Naz et al., 2012) [13] .

Number of fruits per cluster

As shown in Table 3, there was a significant difference in number of fruits per cluster of tomato due to application of different combinations of treatments. At 60 DAT, highest number of fruits per cluster (5.50) was recorded in plants treated with T 8 (0.5% Zn + 0.5% Ca + 0.2% B), which was at par with T 6 (5.06), and least number of fruits per cluster (0.73) was recorded in T 1 (Control). At 90 DAT, significantly higher number of fruits per cluster (6.46) was recorded in T 8, which was at par with T 6 (6.20) and lowest number of fruits per cluster was recorded in T 1 (1.73). At 120 DAT, significantly higher number of fruits per cluster (6.20) was recorded in T 8 , which was at par with T 6 (6.10) and lowest number of fruits per cluster was recorded in T 1 (1.70). Similar results were also reported by the researches of (Harris and Mathuma, 2015) [14] .

Number of fruits per plant

At 60 DAT, highest number of fruits per plant (30.13) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B), followed by T 6 (25.03), and least number of fruits per plant (3.96) was recorded in T 1 (Control). At 90 DAT, significantly higher number of fruits per plant (19.73) was recorded in T 8 ), followed by T 6 (16.03), and lowest number of fruits per plant was recorded in T 1 (1.73) treatment. At 120 DAT, significantly higher number of fruits per plant (6.20) was recorded in T 8 , followed by T 6 (15.63) and lowest number of fruits per plant was recorded in T 1 (3.73). Similar results were also reported by the researches of (Rab and Haq, 2012) [9] , (Harris and Mathuma, 2015) [14] and (Tawab et al., 2015) [15] .

On first picking, maximum diameter of fruit (5.66 cm) was recorded in T 8 treatment and minimum diameter of fruit 2.42 cm was recorded in T 1 . On second picking, significantly higher diameter of fruits (5.90 cm) was recorded in T 8 followed by T 6 (55.50 cm) and minimum diameter of fruit was recorded in T 1 (2.70 cm). At 90 DAT, significantly higher diameter of fruit (5.91 cm) was recorded in T 8 and minimum diameter of fruit was recorded in T 1 (2.57 cm). Similar results were also reported by the researches of (Saravaiya et al., 2014) [16] .

Individual weight of fruits is an important character which directly influences the fruit yield. On first picking, maximum weight of fruit (62.69 g) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B) and minimum weight of fruit (32.81 g) was recorded in T 1 (Control). On second picking, significantly higher weight of fruits (68.75 g) was recorded in T 8 followed by T 6 (61.37 g) and minimum weight of fruit was recorded in T 1 (39.71 g). At 90 DAT, significantly higher weight of fruit (62.19 g) was recorded in T 8 and minimum weight of fruit was recorded in T 1 (36.63 g). Similar results were also reported by the researches of (Tawab et al., 2015) [15] etc. 3.5 Yield per plant (kg), Yield per plot (kg), Yield per hectare (q/ha) As shown in Table 5, there is a significant difference in yield per plant of tomato due to application of different combinations of treatments. Highest yield per plant (1.14 kg) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B), and minimum yield per plant (0.72 kg) was recorded in T 1 (Control). Highest yield per plot (16.96 kg) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B) and minimum yield per plot (9.53 kg) was recorded in T 1 (Control).

Highest yield per hectare (392.77 q) was recorded in T 8 (0.5% Zn + 0.5% Ca + 0.2% B) and minimum yield per plot (220.77q) was recorded in T 1 (Control). Similar results were also reported by the researches of (Verma et al., 2018) [17] etc. Yield of fruits increased significantly with B and Zn combination, because boron regulates water absorption and carbohydrate metabolism (Haque et al., 2011) [12] . Thus, it is likely that higher number of fruits per plant could be due to sufficient levels of carbohydrates available for flower formation and fruit set (Kumar et al., 2004) [18] .

Total Soluble Solids ( 0 Brix)

The highest TSS (5.24 0 Brix) was recorded in plants treated with T 8 (0.5% Zn + 0.5% Ca + 0.2% B) followed by T 6 (0.2% B + 0.5% Zn) (5.02 0 Brix) and T 5 (0.2% B + 0.5% Ca) (4.94 0 Brix). The minimum TSS (4.1 0 Brix) was recorded in T 1 (control). The increase in TSS may be attributed to the growth promoting substances which could have accelerated synthesis of carbohydrates, vitamins and other quality characters (Kumari et al., 2012) [19] .

As shown in Table 6, there is a significant difference in shelf life of tomato fruits due to application of different combinations of treatments. On first picking, longest shelf life (6.33 days) was recorded in T 8 treatment and shortest shelf life (1.46 days) was recorded in T 1 . On second picking, significantly longer shelf life (7.26 days) was recorded in T 8 , and shortest shelf life was recorded in T 1 (1.8 days) treatment. On third picking, significantly higher shelf life (6.80 days) was recorded in T 8 and shortest shelf life was recorded in T 1 (1.66 days). Similar results were also reported by the researches of (Verma et al., 2018) [17] and Salam et al. (2010) [20] .

The highest titrable acidity (0.82%) was recorded in plants treated with T 8 (0.5% Zn + 0.5% Ca + 0.2% B) followed by (0.73%) of T 6 (0.2% B + 0.5% Zn) and T 7 (0.5% Zn + 0.5% Ca) (0.64%). The minimum titrable acidity (0.42%) was recorded in T 1 (control). The increase in titrable acidity may be attributed to the growth promoting substances, enzymes which could have accelerated synthesis of carbohydrates, vitamins and other quality characters. Zinc and boron increases the titrable acidity of fruits (Kumari et al., 2012) [19] . Similar results were also reported by the researches of (Raj et al., 2012) [21] etc.

Conclusion

Foliar application of boron (0.2%), calcium (0.5%) and zinc (0.5%) was found to be the best treatment to improve growth, yield and fruit quality of tomato cv. Azad T-6 under Kanpur subtropical condition having high moderate pH.

Acknowledgement

AcknowledgementThe authors gratefully acknowledge the Department of Vegetable science, College of Horticulture, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, U.P., for providing the essential support and research facilities required for the successful execution of this experiment. 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 this manuscript.

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