Effect of different nano micronutrient on yield of mango (Mangifera indica L.) CV. Amrapali

Introduction

The mango (Mangifera indica L.), a member of the Anacardiaceae family, is a major fruit crop in tropical and subtropical regions. It is believed to have originated in the Indo-Burma region and is recognized as the national fruit of India. Globally, there are more than 11,000 cultivars of Mangifera, with up to 69 genuine species identified (Bose et al., 2001) [4] . The mango has gained worldwide popularity and is one of the principal fruit crops in Asia. In India, thousands of mango varieties are cultivated across a wide range of agroclimatic conditions, including tropical and subtropical zones, humid and semi-humid tropics. Mango trees grow from sea level up to 1200 meters in diverse environments such as wet valleys, riversides, coastal forests, natural grasslands and also in open and disturbed areas like roadsides, pastures and both wet and dry secondary forests (Orwa et al., 2009) [11] . The major mango-growing states in India include Maharashtra, Karnataka, Kerala, Tamil Nadu, Odisha, West Bengal, Gujarat, Uttar Pradeshandhra Pradesh and Bihar. Currently, mangoes are grown in every district of Gujarat; however, due to their ideal agroclimatic conditions, Valsad, Navsari, Surat, Bharuch, Rajkot, Jamnagar, Kutch and Junagadh are the main growing districts. Commercial cultivation of Kesar, Alphanso, Rajapuri, Totapuri, Jamadar, Dashehari, Langra, Amrapali, Mallika, Sonpari and Neelum are the key cultivars across Gujarat. Micronutrients can significantly boost crop yields and improve the quality and shelf life of produce. Their position as enzyme activators and their involvement in lignin production make them important for disease resistance (Parmar et al., 2017) [12] . Nanoparticles (NPs) are nutrient carriers about nano-dimensions (10-9 m) and sizes ranging from 1 to 100 nm. Their high surface area, small size, high reactivity, high dispersibility and superior catalytic activity make them capable to hold large amounts of nutrient ions and aid in ultra-high absorption to enhance crop performance (Subramanian et al., 2015) [14] . Zinc, boron and iron are essential micronutrients that support key plant functions such as growth regulation, reproduction and photosynthesis. Their nano formulations improve foliar absorption and nutrient use efficiency, ultimately enhancing crop productivity under challenging soil conditions. Foliar application of nano micronutrients has emerged as an effective and practical approach in mango cultivation. Challenges such as nutrient fixation in the soil, which limits the availability of essential elements to the crop, have highlighted the need for foliar delivery of these nutrients in nano form. Unlike traditional soil application, which often results in slower plant response, foliar spraying of nano micronutrients ensures faster absorption and mobility within the plant. This method helps prevent deficiencies and potential yield losses in mango before visual symptoms appear, enhancing nutrient use efficiency and supporting healthy crop growth.

Materials and Methods

The experiment was conducted on twenty-year-old trees of mango planted at Horticultural Research Farm, B. A. College of Agriculture, Anand Agricultural University, Anand during 2024. It was carried out using a Completely Randomised Design with nine treatments viz., T 1: Nano Zn 1.0 ml/L, T 2: Nano B 1.0 ml/L, T 3: Nano Fe 1.0 ml/L, T 4: Nano Zn 1.0 ml/L + B 1.0 ml/L, T 5: Nano Zn 1.0 ml/L + Fe 1.0 ml/L, T 6: Nano B 1.0 ml/L + Fe 1.0 ml/L, T 7: Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L, T 8: Micronutrient 1% ZnSO 4 + 0.5% Borax, T 9: water spray repeated twice at 50% flowering and one month after 1 st spray in the year 2024. Each selected tree given 100 kg of well-decomposed FYM and chemical fertilizers comprising 750 g nitrogen (as 1.5 kg urea per plant), 160 g phosphorus (0.35 kg DAP per plant)and 750 g potash (1.25 kg MOP per plant). Half of the nitrogen and all of the phosphorus and potassium were applied in June 2023, with the remaining nitrogen applied in February 2024.

Results and Discussion

Effect of different nano micronutrient on yield parameter No. of fruit set per panicle (at pea stage and at harvest stage)

According to the observations from Table 1, among the various treatments, the treatment T 7 (nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L) had the highest no. of fruit set per panicle (at pea stage) (35.35) and no. of fruit set per panicle (at harvest stage) (1.52). However, T 9 (control) had the lowest number of fruit set per panicle (at pea stage) (19.16). The increase in no. of fruit set per panicle (at pea stage) in mango is attributed to the combined effects of nano zinc, boron and iron on key physiological processes. Zinc promotes auxin production, boron supports pollen germination and iron enhances chlorophyll synthesis and energy generation. Their nano form ensures better absorption and mobility within the plant, improving nutrient efficiency, hormonal balance and photosynthesis, which collectively reduce fruit drop and enhance fruit maturity (Yadav et al., 2011; Deb and Reza, 2024) [15,5] .

No. of fruit per tree (at harvest stage)

Data pertaining to quality parameters presented in Table 1 revealed that the treatment T 7 had the highest no of fruit per tree (363.33), which was at par with treatments T 4 (343.26), T 5 (330.41), T 6 (341.01) and T 8 (349.09). On the other hand, T 9 (control) had the lowest no. of fruits per tree (at harvest stage) (262.00). The application of zinc, boron and iron enhances fruit number per tree by positively influencing physiological processes and enzymatic activity. Zinc supports auxin synthesis and photosynthesis, while boron aids in starch translocation and fruit setting, contributing to better fruit retention and yield. These effects are consistent with findings in strawberry (Kumar, 2021; Kumar et al., 2017) [8] and Washington navel orange (El-Gioushy et al., 2021; Al-Sabbagh et al., 2024) [6,7] .

Table 1 displays the data relating to the mango fruit drop (%) that was impacted by various treatments. The results of the different nano Zn, nano B and nano Fe treatments on the mango fruit drop (%) showed no significant variations.

Table 2 displays the results of the various treatments that had an impact on the fruit weight. Treatment T 7 (Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L) gave highest fruit weight (180.26 g), which was at par with treatments T 4 (172.84 g) and T 8 (170.48 g). Whereas, the control treatment showed minimum fruit weight (145.52 g). The increase in fruit weight may be attributed to the combined effects of zinc, boron and iron-zinc enhances starch production, iron supports cell division and enlargement and boron aids in carbohydrate transport. These nutrients likely improved the mobilization of photo assimilates and boosted cell activity, resulting in heavier fruits. Similar findings have been reported in date palm, olive, pomegranate and mango by various researchers including Mahida et al. (2018) [9] and Kumar (2021) [7] .

The data shows on table 2 represent the effect of different treatments on fruit length (cm). Significantly highest fruit length (10.54 cm) was recorded in treatment T 7 , which was at par with treatments T 4 (9.81 cm) and T 8 (9.86 cm). However, the minimum fruit length (8.53 cm) was found in T 9 (control). This may be due to the combined application of nano zinc, boron and iron likely led to the longest fruit length due to their synergistic effects on hormone regulation, cell elongation and fruit development. Zinc promotes auxin synthesis, boron aids in nutrient transport and structural integrity and iron supports metabolic activity and energy production. In nano form, these nutrients are more efficiently absorbed and utilized by plants, enhancing fruit expansion. Similar results have been reported by Beniwal et al. (2024) [3] and Mosa et al. (2024) [10] .

The data of fruit girth affected by various treatments shown in Table 2. The highest fruit girth (17.31 cm) was achieved by treatment T 7 (Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L), which was at par with treatments T 4 (16.19 cm) and T 8 (16.93 cm). Treatment T 9 (control) showed the minimum fruit girth (14.17 cm). The combined application of nano zinc, boron and iron significantly enhanced fruit girth by promoting cell expansion and overall fruit development. Zinc supported auxin production, boron facilitated cell wall formation and nutrient transport, while iron maintained active metabolism and chlorophyll synthesis during fruit growth. The nano formulation ensured better absorption and nutrient availability, leading to improved internal tissue development. Similar results have been reported by Auda et al. (2022) [2] and Sayed and Gomma (2024) [13] .

The effects of all of the treatments that affected the pulp weight are given in Table 2. Treatment T 7 (Nano Zn 1.0 + B 1.0 ml/L + Fe 1.0 ml/L) generated the highest pulp weight (115.68 g) which was at par with treatments T 4 (110.10 g) and T 8 (107.90 g). Treatment T 9 (control) gave the lowest pulp weight (88.64 g). The combined application of nano iron, boron and zinc enhanced fruit development and resulted in the highest pulp weight. Boron improved sugar transport and cell wall integrity, zinc supported fruit growth and cell division and iron boosted photosynthesis and energy production-key processes for pulp formation. The nano form of these nutrients allowed for faster absorption and efficient transport, leading to better nutrient utilization. This balanced nutrient supply throughout fruit development promoted greater pulp accumulation. Similar findings were reported by Sayed and Gomma (2024) [13] .

The data of mango stone weight affected by various treatments shown in Table 2. The results show that there were non-significant differences in stone weight between treatments as a result of applying nano Zn, nano B and nano Fe.

Stone: pulp ratio

Table 2 shows the result of the different treatments that influenced the stone: pulp ratio. The lowest stone: pulp ratio (0.25) was achieved by treatment T 7 (Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L), which was at par with treatments T 4 (0.26) and T 8 (0.26). As a result, the T 9 (control) treatment showed the maximum stone: pulp (0.32). The combined application of nano zinc, boron and iron enhanced pulp development and reduced the stone: pulp ratio without affecting stone weight, due to improved cell division, nutrient transport and metabolic activity. This coordinated nutrient effect, supported by efficient nano nutrient absorption, led to better internal fruit growth. Similar findings were supported by Sayed and Gomma (2024) [13] and Yadav et al. (2011) [15] Peel weigh (g) and (%) Table 2 shows the result of the different treatments that influenced the peel weight. The highest peel weight (35.19 g) was achieved by treatment T 7 (Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L), which was at par with treatments T 4 (34.30 g) and T 8 (34.27 g). As a result, the T 9 (control) treatment showed the lowest peel weight (27.98 g). Peel (%) was non-significant by the application of nano Zn, nano B and nano Fe throughout all of the treatments. Fruit yield (kg/plant and t/ha) Table 3 shows the results of the several treatments that had an impact on the fruit yield (kg/tree and t/ha). Fruit yield (kg/tree and t/ha) was significantly impacted by the direct application of nano Zn, nano B and nano Fe. The highest fruit yield (63.03 kg/tree and 17.46 t/ha) was obtained from treatment T 7 (Nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L). Treatment T 9 (control) produced the lowest fruits yield (40.43 kg/tree and 11.20 t/ha). The combined use of nano zinc, boron and iron enhances nutrient absorption and key physiological functions, leading to better fruit set, reduced fruit drop, improved fruit growth and significantly higher yields. This is supported by the findings of El-Gioushy et al. (2021) [7] , Al-Sabbagh et al. (2024) [1] .

Conclusion

The result obtained from the research experiment, it can be concluded that the foliar application of nano Zn 1.0 ml/L + B 1.0 ml/L + Fe 1.0 ml/L (two sprayed one at 50% flowering and 2 nd at one month after 1 st spray) treatment was recorded significant effect on yield parameters viz., highest no. of fruit set (at pea and harvest stage), no. of fruit per tree (at harvest stage), fruit length, fruit weight, fruit girth, peel weight and fruit yield (kg/tree and t/ha) and lowest stone:pulp ratio in mango cv. Amrapali.

References

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