INTRODUCTION

The mango is the national fruit of India and is a highly popular among the masses owing to its excellent flavour, delicious taste, delicate fragrance and attractive colour. Inadequate postharvest handling and management cause major losses in nutritional and quality attributes, pathogenic outbreaks, and economical losses all along the supply chain, from farm to fork. Fresh mangoes are perishable in nature that require coordinated activity by growers, storage operators, processors, and retailers to maintain quality and reduce wastage. In mango, major postharvest losses are due to the loss of quality in terms of firmness, high physiological weight loss and spoilage. In spite of the highest production, India contributes a small share of less than 5% in export market due to its postharvest losses. About 20–30% of the fruits grown in India are lost due to improper handling practices (NHB, 2018). However, It is a climacteric fruit, the upsurge in respiration rate after harvesting becomes faster which shortens the shelf life. The shelf life reduction due to rapid fruit ripening, senescence attack of biotic and abiotic stresses (Zhu et al. 2013). The researchers made attempts to extend the shelf life and to reduce spoilage of fruit viz. edible coating (Ali et al. 2011), modifed or controlled atmosphere storage (Martins and Resende 2015), low temperature storage (Aghdam and Bodbodak, 2013), application of fungicides (Sripong et al. 2015), and hot water treatment. Sometimes, due to reduced oxygen level in controlled atmospheric storage develops off-flavor in fruits. There is lacking in availability of storage facilities viz. controlled atmospheric storage and modified atmospheric storage at farmers in India and setting up infrastructures for advanced storage facilities is very costly. Also, a cold chain to manage the time–temperature conditions is adequate for the preservation and transportation of perishables in the proper temperature range to slow down the biological decay processes and deliver safe and high-quality produce to consumers is a lacuna. Hence, preharvest spray of chemicals are very economical to extend the shelf life of fruits.

Potassium plays an important role in photosynthesis, synthesis of carbohydrates, oils, fats and proteins. It is also involved in the transportation of photosynthates towards the sink and enhances the production of protein (Lu et al., 2016). Potassium is an important nutrient for fruit weight and quality. Potassium is required for the production and transport of plant sugars that increase the weight of fruit (Jaiswal et al. 2021). Ethrel releases ethylene gas, influences the growth and development of fruits. Ethrel is responsible for early development of many fruits characterized by a high rate of ethylene evolution and hastens the ripening process with uniform colour development (Dhillon, 2013). Calcium is known to be essential plant nutrient involved in a number of physiological processes concerning membrane structure, function and enzyme activity (Jones and Lunt, 1967). It has received considerable attention in recent years due to its desirable effects in delaying ripening and senescence, increasing firmness, reduce respiration, extending storage life and reducing the incidence of physiological disorders and storage rots. Preharvest application of these compounds hinders the fruit ripening without affecting the edible quality. Preharvest application of CaCl. extends the shelf life and restrict the microbial infection without any detrimental effect and protects against post-harvest deterioration and extend shelf life (Saure, 2005). Gibberellic acid has been found to enhance the fruit size, increase the yield, and improve the physico- chemical characteristics of fruits through modification of various physiological and bio- chemical processes (Pandey and Sinha, 2013). Gibberellic acid in proper concentration and at appropriate time have been found to better results in fruits quality, yield, size, decrease fruit drop, increasing sugar content, improve the physico- chemical characteristics and extend the post-harvest life of fruits through modification of various physiological and bio-chemical processes of plant (Pandey and Sinha, 2013). Gibberellins have been useful in enhancing fruit retention and improving the size and quality of fruits. Further, gibberellic acid has anti-senescent property and help in maintaining cell wall integration and prevents growth of pathogen in the fruits and extend shelf life (Prasad, 2006).

Being a climacteric fruit, weight loss increases rapidly during storage period due to surge in respiration rate and transpiration process. However, it can be minimized by supplementary application of chemicals and plant growth regulators on fruits for maintaining fruit quality and extending their shelf life (Vishwakarma and Masu, 2018; Bisen and Thakur, 2012). Now a day, the mango variety ‘Amrapali’ grown commercially throughout the country because of its dwarf stature. It has very good flavor, taste and high in vitamins and carotenoids content as compared to other verities of mango with a late maturing character, selected for shelf life studies.Considering these points, the present study was designed to study the effect of preharvest spray of different chemicals and plant growth regulators on shelf life extension of mango fruits under ambient storage condition.

MATERIALS AND METHODS

The experiment was conducted at Horticultural Research Farm and Postgraduate Laboratory, Department of Horticulture, Bansilal Amrutlal College of Agriculture, Anand Agricultural University, Anand during summer season of the year 2016. The climate of Anand region is semi-arid and sub-tropical type. The temperature was in the range of 25 to 40 oC with 52 to 73 % relative humidity during experiment time in the month of June, 2016. There were eleven treatments embedded in Completely Randomized Design replicated thrice. Thirty-three uniform sizedfourteen-year old trees of mango var. ‘Amrapali’ were selected and preharvest sprayed with different chemicals (CaCl2 1 %, CaCl2 2 %, Ca(NO3)2 1 %, Ca(NO3)2 2 %, KNO3 1 %, KNO3 2 %), Ethrel 0.1

ml/l and Ethrel 0.2 ml/l) along with control at twenty days before anticipated date of harvest while, GA. 25 mg/l and GA. 50 mg/l were sprayed at marble stage. Mature and uniform sized ten fruits per replication were harvested from the representative trees and kept in ambient storage condition (32±1 oC). When the outer layer of fruits starts to spoil like discoloration, shriveling and visible sign of biotic spoilage Effect of various pre-harvest treatments on shelf life of mango (anthracnose) considered as end of shelf life and noted as spoiled (Rahman et al., 2007).

RESULTS AND DISCUSSION

Effect of preharvest treatments on physical parameters of mango fruit

The fruit size is an important consideration for consumer preference. The effect of treatments on fruit size viz. length and diameter were found to be significant at harvest as well as at fully ripe stage (Table 1). The fruit length (10.20 cm) at harvest stage was found significantly maximum with GA. 25 mg/l treatment followed by the treatments of KNO.1 %, GA3 25 mg/l followed by Ca(NO3)2 1% and 2%, GA3 50 mg/l, Ethrel 0.1 ml/l and KNO. 2%. The significant effect of treatments was found on fruit volume at harvest as well as at fully ripe stage. Preharvest sprayed with GA. 25 mg/l reported significantly highest fruit volume (150.54 cc) at harvest followed by KNO. 1% and at fully ripe stage (fruit volume - 130.62 cc) also found maximum in treatments of GA. 25 mg/l followed by KNO. 1% and Ethrel 0.2 ml/l under ambient storage condition (Table 1). The fruit weight was significantly influenced by various chemicals and plant growth regulators at everyday up to last ripening stage. Application of GA. 25 mg/l Ethrel 0.2 ml/l, GA3 50 mg/l, Ca(NO3)2 1% and 2% while at fully ripe stage significantly maximum fruit length l (10.16 cm) was recorded with GA. 25 mg/ followed by treatments of Ethrel 0.2 ml/l, GA. 50 mg/ l, Ca(NO.). 1% and 2%. The maximum fruit diameter (6.16 cm) at harvest stage was found significant in treatment of GA3 25 mg/l and Ca(NO3)2 1% followed by Ca(NO3)2 2%, CaCl2 1%, GA3 50 mg/l, Ethrel 0.1 ml/l, KNO. 2% while, at fully ripe stage after storage under ambient condition the diameter of fruits (6.14 cm) was found significantly maximum in treatment of depicted significantly maximum fruit weight (170.50 g) at harvest and consistently up to 16th day of storage period under ambient condition as compared to rest of the treatments (Table 2). The lowest fruit weight, length, diameter and volume were recorded in the control at both the stages i.e.at harvest and fully ripe stage.

The fruit size of mango was greatly influenced by different treatments of chemicals. In comparison to all treatments gibberellic acid influenced significantly in terms of fruit weight, volume, length and diameter. It might be due to the involvement of gibberellic acid in promoting cell elongation and cell enlargement of fruit (Jagtap et al. 2013; Lal et al. 2013). As, GA3 level in developing cell is low, the exogenous application of GA3 helps to increase its level in different parts of the fruits, which ultimately helps its growth. The cell elongation stimulated by exogenous gibberellins through altering the rheological properties of the cell wall; as a consequence, the water potential of the cell is lowered allowing for water uptake and greater accumulation of food materials and therefore an increase in cell volume (Derbyshire et al., 2007;

(T1: CaCl2 1%, T2: CaCl2 2 %, T3: Ca(NO3)2 1%, T4: Ca(NO3)2 2%, T5:KNO3 1 %, T6: KNO3 2 %, T7: Ethrel 0.1 ml/l,T8: Ethrel 0.2 ml/l, T9: GA3 25 mg/l, T10: GA3 50 mg/l and T11: Control) results of GA3 sprays are in line with those reported by El-Sese (2005) where Balady mandarin trees sprayed with GA3 resulted in increased yield as of increased fruit weight, length and diameter. The results are also supported by Mostafa et al. (2001) on pear and ElSharkawy and Mehaisen (2005) on guava. KNO3 1 %, T6: KNO3 2 %, T7: Ethrel 0.1 ml/l, T8: Ethrel 0.2 ml/l, T9: GA3 25 mg/l, T10: GA3 50 mg/l and T11: Control) Fig. 1. Effect of preharvest treatments on shelf life (days) of mango var. ‘Amrapali’. periods. Significantly maximum marketable fruit percentage (90.93%) and minimum spoilage (9.07%) were found in treatment of CaCl 2 % followed Marschner (1986) indicated that application of GA3 and/or IAA on higher plants caused elongation in the CaCl21% at 13 and 14th day of storage. Significantly primary cells in the young tissues and growth centers. The bigger size and good quality fruits was also maximum marketable fruit percentage and minimum spoilage were found in treatment of CaCl2 2 %, CaCl 1%, GA 25 mg/l & 50 mg/l after 15th day of observed in plum by González-Rossia et al. (2006)Bhomick and Banik (2011) in mango and Singh et al. (2009) & Katiyar et al. (2008) in guava.

Effect of preharvest treatments on storage studies

storage under ambient condition. Treatment with CaCl. 2 %, also recorded significantly highest marketable fruit percentage and minimum spoilage at 16th day of storage followed by treatment of GA 25 There were significant differences observed in physiological loss in weight due to various preharvest treatments of fruits from harvest to everyday up to 16th day (Table 3). Among the treatments, CaCl. 2 % consistently recorded significantly minimum physiological loss in weight of fruits (1.12 % to 19.91%) from 2nd day to 16th day of storage period respectively, it was found on par with KNO. (2%). The significant effect of various treatments was observed on shelf life of mango fruit during storage periods and CaCl. 2 % was found most effective treatment for extending the shelf life. After storage at ambient temperature CaCl. 2 % was recorded significantly maximum shelf life (16.60 days) compared to rest of the treatments (Fig. 1) while Ethrel treated fruits were recorded lowest shelf life. There was a significant difference observed in the marketable fruit percentage and spoilage of the fruits during storage under ambient condition. The treatments were significantly influenced at harvest and everyday up to last ripening stage (Table 4). There were 100 % marketable fruits and no spoilage in fruits was recorded in all the treatments up to 12th day of storage 15 mg/l and 50 mg/l.

Moisture content of the fruits is an important consideration for its freshness and stability to the storage for a longer duration. The physiological loss in weight in mango fruits was tended to increase during the storage irrespective of the treatments. This could be due to increased moisture loss and enhanced shriveling (Lata et al. 2017). Fruits sprayed with CaCl. 2 % retained the minimum physiological loss in weight and spoilage per cent and maximum shelf life & marketable fruit per cent as compared to rest of the treatments.

As calcium is known to increase fruit cell wall turgidity, serves as a semipermeable membrane, it is also supposed to reduce water diffusion over the fruit cuticle to reduce the differences in osmotic potential, which slows down the evapotranspiration and respiration rate in fruits due to reduced endogenous substrate catabolism and altered membrane permeability (Vercesi et al., 2018). Higher concentrations of CaCl. might be require for the driving force for water diffusion, and to

Effect of various pre-harvest treatments on shelf life of mango

strengthen the walls of epidermal cells that might had resulted in improved resistance to the fruit cell degradation, when the cells meet free flow of water (Sekse, 1997). Preharvest spray of CaCl. restricts the microbial infection without any detrimental effect, maintains cell turgor and delays lipid peroxidation, thereby extending shelf life of fruits (Saure, 2005). The calcium compounds significantly thickened the middle lamella of fruit cells owing to increased deposition of calcium pectate and thereby maintained the cell wall rigidity which inhibits the penetration and spread of pathogens in fruits (Gupta et al. 1987). This could be one of the reasons for reduction in physiological loss in weight and biotic and abiotic spoilage during storage under ambient condition for 2% calcium chloride treated mango fruits. The similar view of results was also reported in persimmon cv. Karaj (Bagheri et al. (2015), in pear cv. Leconte (Sajid et al., 2014), in papaya (Lata et al., 2018; Yadav and Varu, 2013; Ramkrishna et al., 2001), in plum (Kirmani et al., 2013), in mango(Bhusan et al., 2015; Karemera et al., 2014; Singh et al., 2012) and ber (Jawandhaet al., 2009; Yadav et al., 2009) for physiological loss in weight, shelf life and reduce spoilage during ambient storage after calcium treatments.

CONCLUSION

Quality evaluation and maintenance is must to be realized in all segments as consumers will not accept a product when it does not have the requirements or desired quality attributes that may cause major impact on the commercialization chain, especially exportation.The results obtained from present investigation concluded that, GA. 25 mg/l treatment found better in response to improve the physical charactertics of fruit like fruit length, fruit diameter, fruit volume and fruit weight during storage period. Whereas, application of CaCl. 2% effectively improved the shelf life of fruits and marketable fruit percentage while, minimizing the physiological loss in weight and spoilage percentage of fruits under ambient storage condition. The that preharvest spray of calcium chloride is eco-safe and could be done for improving shelf life of mango fruits for better marketability.

Acknowledgments

Authors gratefully thankful for the facility provided by the Anand Agricultural University,Anand, India during the course of this investigation.

REFERENCES

Aghdam, M.S. and Bodbodak, S. 2013. Postharvest heat treatment for mitigation of chilling injury in fruits and vegetables. Food Bioprocess Tech., .:37–53.

Ali, A., Muhammad, M.T.M., Sijam, K. and Siddiqui, Y. 2011. Effect of chitosan coatings on the physicochemical characteristics of Eksotika II papaya (Carica papaya L.) fruit during cold storage. Food Chem., 124:620– 626.

Bagheri, M., Esna-Ashari, M. and Ershadi, A. 2015. Effect of postharvest calcium chloride treatment on the storage life and quality of persimmon fruits (Diospyros kaki thunb.) cv. ‘Karaj’. Int. J. Hortic. Sci. Technol., 2(1):15–26.

Bhowmick, N. and Banik, B.C. 2011. Influence of pre-harvest foliar application of growth regulators and micronutrients on mango cv. Himsagar. Indian J. Hortic., 68(1):103-107.

Bhusan, L.P., Panda, C. and Dash, A.K. 2015. Effect of pre-harvest chemical treatments and mulching on marketability of mango (Mangifera indica L.) cv. Amrapali. J. Crop Weed, 11(1):216-219.

Bisen, S. and Thakur, R.S. 2012. Beneficial effects of pre-harvest application calcium nitrate and gibberellic acid on storage behaviour of guava fruits. JNKVV Research Journal, 46(3):322-327.

Brahmachari, V.S. and Rani, R. 2000. Effect of growth substances on fruit drop, yield and physico-chemical composition of litchi fruits. Prog. Hortic., 32(1):50-55.

Derbyshire, P., McCann, M.C. and Roberts, K. 2007. Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level. BMC Plant Biol., 7(1):1-12.

Dhillon, W.S. 2013. Fruit Production in India.Narendra Publishing House, Delhi, p 383.

El-Sese, A.M.A. 2005. Effect of gibberellic acid (GA3) on yield and fruit characteristics of Balady mandarin. Assiut J. Agric. Sci., 36(1): 23-35.

El-Sharkawy, S.M. and Mehaisen, S.M. 2005. Effect of gibberellin and potassium foliage sprays on productivity and fruit quality of guava trees. Egypt J.Appl. Sci., 20(3):151-162.

González-Rossia, D., Juan, M., Reig, C. and Agusti,M. 2006. The inhibition of flowering by means of gibberellic acid application reduces the cost of hand thinning in Japanese plums (Prunus salicina Lindl.). Sci. Hortic., 110(4):319-323.

Gupta, O.P., Siddiqui, S. and Chauhan, K.S. 1987. Evaluation of various calcium compounds for increasing the shelf life of ber. Indian J. Agric. Res., 21:6570.

Jagtap, V.M., Patel, H.C., Nehete, D.S. and Godage,S.S. 2013. Effect of foliar application of plant growth regulators and micronutrients on yield and quality of acid lime cv. Kagzi (Citrus aurantifolia S.). Asian J. Hort., 8(1):57-59.

Jaiswal, V.P., Shukla, S.K., Sharma, L., Singh, I., Pathak, A.D., Nagargade, M. and Masto, E. 2021. Potassium influencing physiological parameters, photosynthesis and sugarcane yield in subtropical India. Sugar Tech., 23(2):343- 359.

Jawandha, S.K., Mahajan, B.V.C. and Gill, P.S. 2009. Effect of pre-harvest treatments on the cellulase activity and quality of ber fruit under cold storage conditions. Not. Sci. Biol., 1(1):88.

Jones, R.W. and Lunt, O.R. 1967. The function of calcium in plants. Bot. Rev., 33(4):407-426.

Karemera, N.U., Mukunda, G.K., Ansar, H. and Taj, A. 2014. Effect of calcium chloride sprays on ripening, shelf-life, physico- chemical parameters and organoleptic evaluation of mango fruits (Mangifera indica L.) cv. Totapuri. Plant Arch., 14(1):121-124.

Katiyar, P. N., Singh, J. P., Singh, P. C. and Gangwar, A.P.S. 2008. Effect of preharvest application of plant growth regulators on post-harvest quality of organically grown guava (Psidium guajava L.) fruits. Asian J. Hort., 3(2):330-332.

Kirmani, S.N., Wani, G.M., Wani, M.S., Ghani, M.Y., Abid, M., Muzamil, S., Raja, H. and Malik, A.R. 2013. Effect of preharvest application of calcium chloride (CaCl.) and Gibberellic Acid (GA.) and Naphthalene Acetic Acid (NAA) on storage of plum (Prunus salicina L.) cv. Santa Rosa under ambient storage conditions. Afr. J. Agric. Res., 8(9):812-818.

Lal, N., Das, R.P. and Verma, L.R. 2013. Effect of plant growth regulators on flowering and fruit growth of guava (Psidium guajava L.) cv. Allahabad Safeda. Asian J. Hort., 8(1):54-56.

Lata, D., Aftab, M.A., Homa, F., Ahmad, M.S. and Siddiqui, M.W. 2018. Effect of eco-safe compounds on postharvest quality preservation of papaya (Carica papaya L.). Acta Physiol. Plant., 40(1):1-8.

Lu, Z., Lu, J., Pan, Y., Lu, P., Li, X., Cong, R. and Ren, T. 2016. Anatomical variation of mesophyll conductance under potassium deficiency has a vital role in determining leaf photosynthesis. Plant, Cell Environ., 39(11): 2428-2439.

Marschner, H. 1986. Mineral nutrition of higher plants. Academic press. London, p. 674.

Martins, D.R. and Resende E.D. 2015. External quality and sensory attributes of papaya cv. Golden stored under diferent controlled atmospheres. Postharvest Biol. Technol., 110:40–42.

Mostafa, E.A.M., Saleh, M.M. and Abd El-Migeed, M. 2001. Improving Le Conte pear trees productivity by spraying, GA. and sucrose. Arabb. Univ. J. Agric. Sci., 9(1):373-385.

NHB, National Horticulture Board 2018. Indian Horticulture Database 2018. Gurgaon, Haryana.

Pandey, S. N. and Sinha, B. K. 2013. Plant Physiology (4th ed.). Vikas Publishing House Pvt. Ltd, Noida, Uttar Pradesh.

Prasad, B. 2006. Effect of PGR’s on bearing and keeping quality of mango (Mangifera indica L.) cv. Amrapali. Ph.D. thesis, BAU, Ranchi.

Rahman, M. S. 2007. Handbook of food preservation. CRC press, p 6-7.

Ramakrishna, M., Haribabu, K., Reddy, Y.N. and Purushotham, K. 2001. Effect of pre-harvest application of calcium on physico-chemical changes during ripening and storage of papaya. Indian J. Hortic., 58(3):228-231.

Sajid, M., Mukhtiar, M., Rab, A., Syed, T.A. and Jan, I. 2014. Infuence of calcium chloride (CaCl.) on fruit quality of pear (Pyrus communis) cv. Le Conte during storage. Pak. J. Agric. Sci., 51(1):113–121.

Saure, M.C. 2005. Calcium translocation to feshy fruit: its mechanism and endogenous control. Sci. Hortic., 105:65–89.

Sekse, L. 1997. Fruit cracking mechanisms in sweet cherries (Prunus avium L.)-a review. In III International Cherry Symposium, 468:637- 648).

Singh, A.K., Singh, C.P. and Chauhan, P. 2012. Effect of pre-harvest chemical treatments and mulching on quality and marketability of Dashehari mango. Indian J. Hortic., 69(4):462-466.

Singh, B., Singh, S., Zubair, M. and Chandi, K.S. 2009. Effect of pre-harvest application of nutrients and bio-regulators on fruit quality, yield and post-harvest performance of Sardar guava. Haryana J. Hort. Sci., 38:70-71.

Sripong, K., Jitareerat, P., Uthairatanakij, A., Srilaong, V., Wongs-Aree, C., Tsuyumu, S. and Kato, M. 2015. Efects of hot water, UV- C and modifed coconut oil treatments on suppression of anthracnose disease and maintenance of quality in harvested mango cv. ‘Chok-Anan’. .. Food Nutr. Sci., 3(2):1-8.

Vercesi, A.E., Castilho, R.F., Kowaltowski, A.J., de Oliveira, H. C., de Souza-Pinto, N. C., Figueira, T.R. and Busanello, E.N. 2018. Mitochondrial calcium transport and the redox nature of the calcium-induced membrane permeability transition. Free Radic. Biol. Med., 129:1-24.

Vishwakarma, P.K. and Masu, M.M. 2018. Effect of preharvest application of different chemicals and plant growth regulators on biochemical parameters of mango (Mangifera indica L.) var. Amrapali. Int. J. Agric. Sci., 14(1):92-96.

Yadav, I., Sharma, R.K., Goyal, R.K. and Siddiqui,S. 2009. Effect of pre-harvest sprays of calcium on the storage of ber (Zizyphus mauritiana Lamk.) cv. Umran. Haryana J. Hort. Sci., 38:243-246.

Yadav, L. and Varu, D.K. 2013. Effect of pre harvest and post-harvest dipping of fruits on shelf life and quality of papaya. Asian J. Hort. 8(2):581–587.

Zhu, X., Li, X., Chen, W., Lu, W., Mao, J. and Liu,T. 2013. Molecular cloning, characterization and expression analysis of cpcbf2 gene in harvested papaya fruit under temperature stresses. Electron. J. Biotechnol., 16(4):1-10.