Standardization of time of pruning and use of PGR for growth, yield, and quality in custard apple (Annona squamosa L.) Cv. Balanagar

Introduction

Custard apple (Annona squamosa L.), being a dryland crop, exhibits adaptability to a diverse range of soil and climatic conditions. Notably, it is relatively resilient against serious pest and disease issues, resulting in lower production expenditure. The climatic conditions in Maharashtra are particularly conducive to custard apple cultivation, further enhancing its suitability. Due to these favourable factors, there is considerable potential for expanding the cultivation area, increasing production volumes, and enhancing the overall productivity of custard apple in the region. Maharashtra stands as the leading state in custard apple production within the country, contributing significantly with a production volume of 92,320 tons. The major custard apple growing districts in Maharashtra include Beed, Pune, Buldhana, Nagpur, Dhule, Chhatrapati Sambhaji Nagar, Ahilyanagar, Akola and Solapur. Notably, the custard apples from Beed received a Geographical Indication Tag (GI) in 2016, underscoring the uniqueness and distinctiveness of the produce from this region. Custard apple plants, being deciduous, exhibit a natural response to stress by shedding their leaves, a mechanism that aids in preventing moisture loss through transpiration. This characteristic renders custard apple an ideal fruit crop for rainfed regions (Kumar et al., 2018) [16] .

The climatic conditions in Maharashtra further enhance the suitability for custard apple cultivation, particularly during the Kharif season, requiring minimal efforts and reduced expenditure. Custard apple, a delectable dryland fruit, offers numerous health benefits and is characterized by its nutritional richness. The fruits are notably low in saturated fat, cholesterol, and sodium, making them a wholesome choice. Custard apple has significantly diversified the range of available food options by offering a variety of nutrients, making it a rich source of carbohydrates, protein, fiber, and essential minerals like calcium, phosphorus, iron, and vitamin C. Recognized as a substantial energy source with a value of 104 Kcal, the fruit composition per 100 grams of pulp includes carbohydrates (23.5 g), moisture (70.5%), protein (1.6 g), minerals (0.9 g), fiber (3.1 g), calcium (17 mg), phosphorus (47 mg), iron (1.5 mg), and vitamin C (37 mg) (Parekh and Sharma, 1993) [24] . Beyond its role as a dietary component, various parts of the custard apple, including its immature fruits, seeds, leaves, bark, and roots, are utilized for medicinal purposes (Datta, 2017) [6] . This comprehensive nutritional profile and medicinal versatility make custard apple a valuable addition to both diet and traditional healthcare practices. The high dietary fibre content further aids in digestion, as noted by Navaneethakrishnan and Nattar in 2011 [19] . Recognizing its nutritional value, custard apple has become an integral part of promoting good health. Pruning plays a pivotal role in custard apple cultivation, significantly influencing tree vigour, productivity, and fruit quality. It serves a dual purpose, not only enhancing fruit quality but also establishing a robust framework during the early stages to augment the fruit-bearing area. As the tree ages, neglecting regular annual pruning can result in weakened structures, compromising both fruit size and quality. Therefore, consistent pruning during the bearing stage is crucial, promoting the development of healthy shoots that contribute to optimal fruit-bearing area and the production of high-quality fruits in Guava (Bajpai et al., 1973) [1] .

Materials and Methods

The study was carried out on "Standardization of time of pruning and use of PGR for growth, yield, and quality in Custard apple (Annona squamosa L.) Cv. Balanagar

Results and Discussions

Days to sprouting (from pruning)

The data from Table 1 showed that, effect of time of pruning was found to be significant. Significantly minimum number of days to sprouting (15.08 days) was found in treatment P 3 followed by treatment P 1 (16.08 days). This could be because pruning allows the plant to accumulate more carbohydrates, ensuring that sufficient nutrients are available for its metabolic and physiological processes, the timing of pruning aligning more closely with the optimal physiological state of the plant, which may enhance the growth rate. The more sprouting time observed in P 1 and P 4 could be due to suboptimal environmental conditions or physiological states at those pruning times, leading to delayed sprouting. These findings are in accordance with result reported by Suleman et al. (2006) [30] in guava, Ghum (2011) [7] , Jadhav et al. (2020) [10] , Jadhav et al. (2022) [11] in custard apple, Patil et al. (2018) [26] in acid lime. Different levels of plant growth regulators significantly influenced the days to sprout which was minimum number of days to sprout (15.68 days) in treatment G 3 (75 ppm) followed by days to sprout (16.75 days) in treatment G 2 (50 ppm). Interaction effects due to time of pruning and use of plant growth regulator was found significant on days to sprout analysis. Significantly minimum number of days to sprout (14.25 days) was found in treatment P 3 (15 th May pruning) and higher concentration of NAA (75 ppm) (G 3 ) i.e. treatment T 9 (P 3 G 3 ) followed by treatment T 6 (P 2 G 3 i.e. 15 th April pruning + 75 ppm) (14.75 days), treatment T 5 (P 2 G 2 i.e. 15 th April pruning + 50 ppm) (16.25 days) during experiment. However, maximum days to sprouting (20.25 days) was recorded in treatment T 13 (control). The use of NAA spray also influenced the sprouting time, with 75 ppm (G 3 ) (15.68 days) showing the best results. NAA is known to promote cell division and elongation, which might explain the reduced sprouting time. The differences between G 1 , G 2 , and G 3 suggest that the concentration of NAA plays a crucial role, with 75 ppm (G 3 ) likely representing an optimal concentration for promoting faster sprouting. These findings are in accordance with result reported by Lokesha et al. (2022) [17] , Prajapati et al. (2016) [27] in custard apple cv. Local.

Number of shoots emerged per branch

The data from Table 1 showed that, effect of time of pruning on number of shoots per branch was found to be significant during experiment. Significantly maximum number of shoots per branch (168.58) was found in Treatment P 3 (15 th May). This suggests that P 3 is the optimal time for pruning to maximize vegetative growth. Pruning at this time might coincide with a period when the plant is most responsive to such interventions, possibly due to favourable environmental conditions or the physiological state of the plant. The reason is that pruning might lead to peripheral buds, release due to the elimination of terminal buds and therefore elimination of apical dominance. Therefore, the number of branches formed after pruning increases. These results are in line with the experimental findings of Singh et al. (2001) [29] and Nikumbhe et al. (2017) [20] in guava, Jadhav et al. (2020) [10] and Jadhav et al. (2022) [11] in custard apple and Kshirsagar et al. (2020) [14] in mango. Different levels of plant growth regulators significantly influenced the number of shoots per branch which was maximum number of shoots per branch (167.93) with higher concentration of NAA (75 ppm) during experiment. Interaction effects due to time of pruning and use of plant growth regulator was found significant on number of shoots per tree analysis. Significantly maximum number of shoots per tree (173.50) was found in treatment P 3 (15 th May pruning) and higher concentration of NAA (75 ppm) (G 3 ) i.e. treatment T 9 (P 3 G 3 ) followed by treatment T 6 (P 2 G 3 i.e. 15 th April pruning + 75 ppm) (170.75), treatment T 8 (P 3 G 2 i.e. 15 th May pruning + 50 ppm) (168.50), treatment T 12 (P 4 G 3 i.e. 15 th June pruning + 75 ppm) (168.50) during experiment. Interaction effects due to time of pruning and use of plant growth regulator was found significant on number of shoots per tree analysis. However, minimum number of shoots per branch (145.25) was recorded in water spray i.e. in treatment T 13 (control). The application of NAA also impacts branching, with G 3 (167.93) showing the greatest effect. This result suggests that the concentration of NAA used in G 3 is most effective at promoting branching. NAA likely stimulates shoot initiation and development, leading to a higher number of branches.

Days to flowering (from pruning)

The data from Table 1 showed that, effect of time of pruning was found to be significant. Significantly minimum number of days to flowering (34.91 days) was recorded in treatment P3 followed by treatment P 2 (35.58 days). The 15 th May pruning (P 3 ) resulted in the highest flower production per shoot. This may be due to the optimal balance between vegetative growth and flowering, as 15 th May pruning might stimulate the plant to allocate more resources toward reproductive growth. In contrast, 15 th March pruning (P 1 ) led to the fewest flowers per shoot, possibly because the plant may still be focusing on vegetative growth and recovery after pruning. The results demonstrate that both pruning time and the application of NAA significantly affects the days to flowering in custard apple. Treatment P 3 resulted in the earliest flowering, which might be due to optimal synchronization with the plants physiological state, allowing for a quicker transition from vegetative to reproductive phases. The result of present finding is in agreement with the finding of Jadhav et al. (2022) [11] in guava, Mohamed et al. (2010) [18] in custard apple. Different levels of plant growth regulators significantly influenced the days to flowering which was minimum number of days to flowering (36.12 days) in treatment G 3 followed by days to flowering (37.18 days) in treatment G 2 . Interaction effects due to time of pruning and use of plant growth regulator was found significant on days to flowering. Significantly minimum days to flowering (34.50 days) was found in treatment P 3 (15 th May pruning) and higher concentration of NAA (75 ppm) (G 3 ) i.e. treatment T 9 (P 3 G 3 ) followed by treatment T (control). The NAA spray at G 3 concentration effectively reduced the days to flowering. NAA is known to influence the timing of flowering by affecting hormonal balance, particularly by modulating the levels of auxin and gibberellins, which are critical in the transition from vegetative to reproductive growth. This might be due to the C:N ratio which helps in balanced management of vegetative and reproductive phases and there by early flowering. The above results were in agreement with those of Prajapati et al. (2016) [27] in custard apple and Goswami et al. (2013) [8] in pomegranate.

Number of flowers per shoot

The data from Table 1 showed that, effect of time of pruning was found to be significant. Significantly maximum number of flowers per shoot (18.41) was found in Treatment P 3 followed by P 4 (16.75). The treatment P 3 resulted in the highest flower production per shoot. This may be due to the optimal balance between vegetative growth and flowering, as 15 th May pruning (P 1 ) might stimulate the plant to allocate more resources toward reproductive growth. In contrast, 15 th March pruning (P 1 ) led to the fewest flowers per shoot, possibly because the plant may still be focusing on vegetative growth and recovery after pruning. Severe pruning had a more detrimental effect on flowering compared to mild pruning. The reduction in the number of flowers in severely pruned branches is likely due to the loss of potential fruitbearing wood. This could explain why mildly pruned branches produced a higher number of flowers. The result of present finding is in agreement with the finding of Jadhao et al. (2002) [9] in guava, Mohamed (2010) [18] in custard apple, Dahapute et al. (2018) [5] in custard apple, Singh et al. ( 2001) [29] in guava. Different levels of plant growth regulators significantly influenced the number of flowers per shoot which was maximum per shoot (17.31) in treatment G 3 followed by number of flowers per shoot (16.18) in treatment G 2 . Interaction effects due to time of pruning and use of plant growth regulator was found significant on number of flowers per shoots. Significantly maximum number of flowers per shoot (19.75) was found in treatment P 3 (15 th May pruning) and higher concentration of NAA (75 ppm) (G 3 ) i.e. treatment T 9 (P 3 G 3 ) followed by treatment T 8 (P 3 G 2 i.e. 15 th May pruning + 50 ppm) (18.25), treatment T 6 (P 2 G 3 i.e. 15 th April pruning + 75 ppm) (18.00), treatment T 12 (P 4 G 3 i.e. 15 th June pruning + 75 ppm) (17.75), treatment T 7 (P 3 G 1 i.e. 15 th May pruning + 25 ppm) (17.25) during experiment. However, minimum number of flowers per shoot (9.50 days) in treatment T 13 (control). The application of NAA at G 3 concentration resulted in the highest flower production. NAA is known to influence the plants hormonal balance, promoting flowering by enhancing the synthesis of gibberellins and reducing the levels of inhibitory hormones such as abscisic acid. These findings are consistent with other studies on fruit trees, such as those by Hossain et al. (2018) in mango and Singh et al. (2017) [28] in guava, where plant growth regulators have been shown to significantly increase flower production when applied at optimal concentrations. The increase in number of flowers per shoot, might be due to plants remain physiologically more active to build up sufficient food stock for the developing flowers and fruits production, ultimately resulted into flower set. The above results were in agreement with those of Chaudhari et al. (2016) [2] , Lokesha et al. (2022) [17] in custard apple and Chavan et al. (2009) [4] in sapota. Interaction effects due to time of pruning and use of plant growth regulator was found non-significant on number of flowers per shoot.

The data from Table 1 showed that, effect of time of pruning was found to be significant. Significantly maximum fruit retention (47.94 %) was found in treatment P 3 . The treatment P 3 resulted in the highest fruit retention (%). This suggests that P 3 pruning might enhance the plant ability to support a larger number of fruits, potentially due to better carbohydrate allocation and improved overall plant health during the critical fruit-setting period. In contrast, treatment P 1 led to the lowest fruit retention, likely because the plants had less time to recover and build up resources needed to sustain fruit development. Different levels of plant growth regulators significantly influenced the use of plant growth regulator which was maximum fruit retention (45.38 %) in treatment G 3 . Interaction effects due to time of pruning and use of plant growth regulator was found significant on fruit retention percentage. Significantly maximum fruit retention (52.45 %) was found in treatment P 3 (15 th May pruning) and higher concentration of NAA (75 ppm) (G 3 ) i.e. treatment T 9 (P 3 G 3 ) during experiment. However, minimum fruit retention (36.08 %) was recorded in treatment T 13 (control) during experiment. The G 3 treatment, which had the highest concentration of NAA, resulted in the greatest fruit retention. NAA is known to reduce fruit drop by improving the strength of the fruit attachment to the plant, likely through its effects on enhancing cell wall integrity and reducing ethylene production, which is responsible for fruit abscission. The enhancement effect of NAA sprays on fruit retention (%) may be due to auxin, it is well known as inhibitors for abscisic acid and ethylene which cause fruit drop so, application of auxin (NAA), which would be helpful in increasing auxin level and thereby resulted in reduce fruit drop. The NAA being auxin compound might have reduced the cellulose activity and the abscission process which would have resulted in increased fruit retention. The response of NAA in increasing fruit retention confirms the earlier findings of Kulkarni (1993) in custard apple. These results are in confirmation with result obtained by Patel et al. (2010) [25] , Chaudhary (2013) [3] in custard apple; Osama et al. (2015) [22] and Nkansah et al. (2012) [21] in mango. Pal and Ghosh (2019) [23] in pomegranate Kassem et al. (2011) [13] in ber.

Days required for last harvesting (from pruning)

The data from Table 1 showed that, effect of time of pruning was found to be significant. Significantly the minimum days required for last harvesting (112.33) was recorded in treatment P 4 while maximum (133.50 days) was found in treatment P 1 . The P 4 treatment, which involves the last pruning time, resulted in the earliest last harvesting, suggesting that later pruning may accelerate the overall growth and fruiting cycle. This could be due to the fact that later pruning might better align the vegetative growth phase with the optimal conditions for fruit maturation, leading to a shorter harvesting period. Conversely, the earliest pruning (P 1 ) led to the longest time to last harvest, likely because the trees require more time to recover from the 15th March pruning and complete the fruiting cycle. Pruning stimulates strong, vigorous, and juvenile growth in the vegetative parts of the plant. This suggests that pruned plants require a longer period to reach physiological maturity. Various pruning intensities on previous seasons shoots have shown significant results. i.e. the minimum number of days were observed in control pruning of previous year shoots, followed by 25 % pruning and 50 % pruning reported by Ghum (2011) [7] in custard apple. The above results were in agreement with those of Jadhav et al. (2022) [11] , Pal and Ghosh et al. (2019) [23] [31] in gooseberry and Kacha et al. (2012) [12] in phalsa.

Conclusion

On the basis of present investigation, the findings suggest that adopting a 15th May pruning schedule, combined with higher concentrations of NAA (75 ppm), is the most effective strategy for enhancing the growth, yield, and quality of custard apples. significantly improved growth parameters, such as early sprouting and flowering, the maximum number of shoots and flower, and maximum fruit retention and days for last harvesting.

Acknowledgement

We are very thankful to the Post Graduate Institute and All India Coordinated Research Project on Arid Zone Fruit, MPKV, Rahuri for providing all facilities and research grants to carry out this experimental work and authors cited in references for providing necessary literature material.

References

1. Bajpai PN, Shukla HS, Chuturvedi AM. Effect of pruning on growth, yield and quality of guava var. Allahabad Safeda. Prog Hortic. 1973;2(4):73-79.
2. Chaudhari JC, Patel KD, Yadav L, Patel UI, Varu DK. Effect of plant growth regulators on flowering, fruit set and yield of custard apple (Annona squamosa L.) cv. Sindhan. Adv Life Sci. 2016;5(4):1202-1204.
3. Chaudhari J. Effect of growth regulators on fruit set, yield and quality of custard apple (Annona squamosa L.) cv. Sindhan. Thesis submitted to Department of Horticulture, College of Agriculture, JAU, Junagadh; 2013.
4. Chavan SR, Patil MB, Phad GN, Suryawanshi AB. Effect of growth regulators on flowering and yield of sapota (Manilkara achras (Mill.) Forsberg). Asian J Hortic. 2009;4(1):119-20.
5. Dahapute VM, Joshi PS, Tayade SA, Nagre PK. Effect of severity of pruning on growth, yield and quality of custard apple. Int J Chem Stud. 2018;6(2):1606-1609.
6. Datta AK. Review on the uses and good side of custard apple from the tribal area of Chhattisgarh. World J Pharm Sci. 2017;6(2):1397-403.
7. Ghum SS. Effect of time and pruning intensities on growth, yield and quality of custard apple. MSc (Agri) Thesis submitted to M.P.K.V., Rahuri. 2011.
8. Goswami JD, Patel NM, Bhadauria HS, Wankhade VR. Effect of plant growth substances on growth, fruit setting and yield of Pomegranate cv. Sinduri. Int J Agric Sci. 2013;9(1):332-334.
9. Jadhao BJ, Mahurkar VK, Kale VS. Effect of time and severity of pruning on growth and yield of guava. Orissa J Hortic. 2002;30(2):83-87.
10. Jadhav AR, Chole AS, Dheware RM, Kadam SR. Effect of different level of pruning on growth and yield of custard apple. Int J Curr Microbiol Appl Sci. 2020; special issue-11:228-231.
11. Jadhav KP, Panchbhai DM, Patil SR, Bahadure A, Ramteke NH. Effect of severity of pruning and fruit retention on growth and harvesting of custard apple. Pharma J. 2022;11(9):1122-1126.
12. Kacha HL, Jat G, Patel SK. Performance of various plant growth regulators on yield and quality of phalsa (Grewia asiatica L.). HortFlora Res Spectrum. 2014;3(3):292294.
13. Kassem HA, Al-Obeed RS, Ahmed MA, Omar AKH. Productivity, fruit quality and profitability of Jujube trees improvement by preharvest application of agrochemicals. Middle-East J Sci Res. 2011;9(5):628-637.
14. Kshirsagar AV, Kulkarni SS, Magar SD. Effect of different beheading levels on initial growth parameters of Mango under high density planting cv. Keshar and Vanraj. J Pharmacogn Phytochem. 2020;6(5):20752077.
15. Kulkarni SS. Effect of cultural and chemical treatments on fruit set, yield and quality of custard apple (Annona squamosa L.). MSc Thesis submitted to MPKV Rahuri. 1993.
16. Kumar D, Kumar A, Kumar V, Kumar M, Prakash S. Effect of Bio-Regulators on Improvement in Chemical Traits, Storage Life and Organoleptic Quality of Ratol Mango. Int J Curr Microbiol Appl Sci. 2018;7(8):38023810.
17. Lokesha R, Athani SI, Gollagi SG, Sanjeevraddi GR, Nadaf AM, Prasanna SM, Patil DR. Effect of different plant growth regulators on flowering and fruit set of custard apple (Annona squamosa L.) cv. Balanagar under northern dry zone of Karnataka. Pharma Innov J. 2022;11(9):2135-2139.
18. Mohamed FM, Shahein EZ, Abd El-Motty F, Fawzi MI. Effect of pruning, defoliation and nitrogen fertilization on growth, fruit set and quality of Abdel-Razik Annona cultivar. Nature Sci. 2010;8(12):281-287.
19. Navaneethakrishanan K, Nattur S. Custard apple. Kisan World. 2011:15-19.
20. Nikumbhe PH, Musmade AM, Mali DS, Patil RS. Impact of Pruning Time on Shoot Initiation, Shoot Sprouting, Fruit Yield and Fruit Fly Incidence in Guava. Int J Pure Appl Biosci. 2017;5(2):513-518.
21. Nkansah GO, Ofosu-Animand J, Mawuli A. Gibberelic acid and Naphthalene Acetic Acid affect fruit retention, yield and quality of Keitt Mangoes in the Coastal Savanna Ecological Zone of Ghana. Am J Plant Physiol. 2012;7(6):243-251.
22. Osama HM, Amro SM, Saber MM. Effect of growth regulators, antioxidant and application date on fruiting and fruit quality of mango tree cv. Keitt. J Agric Vet Sci. 2015;8(12):87-95.
23. Pal R, Ghosh SN. Effect of shoot pruning on yield and fruit quality of custard apple cv. Balanagar. Int J Minor Fruits Med Aromatic Plants. 2019;5(2):50-52.
24. Pareekh OP, Sharma S. Custard apple. Indian Horticulture. 1993 Apr-Jun:47-56.
25. Patel NM, Patel DK, Varma LR, Patel MM. Effect of cultural and chemical treatments on fruit set and fruit yield of custard apple (Annona squamosa L.) cv. Sindhan. Asian J Hortic. 2010;5(2):498-502.
26. Patil SR, Bichkule SM, Sonkamble AM. Effect of severity and time of pruning on growth, flowering and fruit set of hasta bahar in acid lime. Int J Curr Microbiol Appl Sci. 2018;6(2):968-974.
27. Prajapati RD, Laua HN, Solanki PD, Parekh NS. Effect of plant growth regulators on flowering, fruiting, yield and quality parameters of custard apple (Annona squamosa L.). Econ Environ Conserv. 2016; 22:177179.
28. Singh AK, Singh CP, Bora L. Impact of pruning on growth, yield and quality of mango cv. Dashehari. J Hortic Sci. 2017;12(2):118-123.
29. Singh G, Singh K, Rajan S. Influence of pruning date on fruit yield of guava (Psidium guajava L.) under subtropics. J Appl Hortic. 2001;3(1):37-40.
30. Suleman M, Sharma JR, Kumar R, Gupta RB, Singh S. Effect of pruning on growth and cropping in guava cv. Lucknow 49. Haryana J Hortic Sci. 2006;35(3):211-212.
31. Yadava LP. Effect of growth retardants on floral biology, fruit set and fruit quality of Cape Gooseberry (Physalis peruviana L.). Am J Plant Physiol. 2012;7(3):143-148.