Effect of application of paclobutrazol and fertilizer dose on infloresence and yield of mango (Mangifera indica L.) Cv. Kesar

Introduction

Mango (Mangifera indica L. 2𝑛 = 40), belonging to the family Anacardiaceae, is an important tropical fruit crop and is popularly known as the "King of Fruits". It is believed to have originated in the Indo-Burma region and has been cultivated in the Indian subcontinent for more than 4,000 years. Its pleasant aroma, attractive flavour, succulent pulp and high nutritional value make it one of the most valued fruit crops. Kesar is a superior chance seedling selection from Junagadh, Gujarat, known for its attractive fruit colour, excellent eating quality, intense sweetness and characteristic aroma. It originated in the foothills of Girnar and received the Geographical Indication (GI) tag in 2011 due to its distinctive quality and regional identity. Irregular, alternate and shy bearing are major constraints in mango production. Paclobutrazol (PBZ), a gibberellin biosynthesis inhibitor, is widely used to regulate vegetative growth and promote flowering in mango. It inhibits the conversion of kaurene to kaurenoic acid, thereby reducing vegetative growth and favouring reproductive development. Soil application of PBZ during July-August has been reported to induce flowering during October-November and advance fruit maturity (Voon et al., 1989) [1] . Nutrient availability is another important factor influencing mango growth, yield and fruit quality. Adequate and balanced fertilization is essential for maintaining vegetative growth, flowering and fruit development. Nutrient requirement also varies with the stage of crop growth; therefore, proper fertilizer dose, timing and method of application are important for achieving optimum productivity. Thus, the combined use of paclobutrazol and appropriate fertilizer management may help regulate vegetative growth, improve flowering and fruiting, and enhance yield and fruit quality. Hence, the present investigation was undertaken to study the effect of paclobutrazol and fertilizer application on growth, yield and quality of mango cv. Kesar.

Materials and Methods

The present study entitled "Effect of Application of Paclobutrazol and Fertilizer Dose on Growth of Mango (Mangifera indica L.) cv. Kesar" was conducted during 2025-26 at the Experimental-cum-Research Mango Orchard, Department of Horticulture, College of Agriculture, Latur, VNMKV, Parbhani. The experiment was laid out in a factorial randomized block design (FRBD) comprising two factors, viz., paclobutrazol dose (D) and fertilizer dose (F), with eight treatment combinations and three replications. Paclobutrazol (PBZ, 23% active ingredient) was applied as a single soil application. The required quantity was diluted in 5 L of water and uniformly applied in a ring at 1 m distance from the tree trunk. Fertilizers were applied by the ring method through a 3-5 inch deep trench around the tree canopy at the respective growth stages. Observations were recorded on flowering and yield parameters, including days to panicle emergence, panicle length, number of panicles per tree, fruit weight, yield per tree and yield per hectare. The observations were recorded through manual measurements and counting and subjected to statistical analysis. Factor A: Paclobutrazol dose (D)

Results and Discussion

Flowering parameters

Days of panicle emergence

Effect of Paclobutrazol Dose (D):

The application of paclobutrazol significantly reduced the days required for panicle emergence, with the effect being more pronounced at higher doses. The minimum days for panicle emergence (46.06 days) was recorded with dose of paclobutrazol @ 2.5 ml a.i. (D 4 ), which was statistically at par D 3 (47. 19) with the dose of paclobutrazol @ 2.0 ml a.i. followed by (50.85 days) was recorded @ 1.5 ml a.i. (D 2 ). The maximum days to panicle emergence (52.06 days) were recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). The earlier panicle emergence under higher PBZ doses may be attributed to the suppression of gibberellin biosynthesis, which reduces vegetative growth and favours reproductive development. Increased carbohydrate accumulation and a favourable C ratio may further support floral initiation by providing the metabolites and energy required for flower bud differentiation. This finding is similar to that of Sarker et al. (2012) [2] , where paclobutrazol induced flowering 85 days after treatment application.

Effect of Fertilizer Dose (F):

The effect of different dose of fertilizer application on days of panicle emergence was found to be significant. The minimum days of panicle emergence (47.99) were recorded with the dose F 2 (50% of N, 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the maximum days of panicle emergence (50.09) were recorded with the dose F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August). Patel et al. (2018) [3] reported that NPK application in post-monsoon months significantly reduced days to flowering in cv. Kesar attributed to better nutrient assimilation and physiological readiness of the trees.

Interaction Effect (DxF):

The interaction effect of application of paclobutrazol and fertilizer dose on days of panicle emergence was found to be non-significant.

Number of panicles per tree

Effect of Paclobutrazol (D):

The effect of different dose of paclobutrazol on number of panicles per tree was found to be significant. The maximum number of panicles per tree (642.74) was recorded with the dose of paclobutrazol @ 2.5 ml a.i. (D 4 ) which was statistically at par with D 3 (609.03) with the dose @ 2.0 ml a.i. followed by (535.95) with the dose of paclobutrazol @ 1.5 ml a.i. (D 2 ). The minimum number of panicles per tree (500.03) was recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). Yeshitela et al. (2004) [4] reported that the higher number of panicles observed in paclobutrazoltreated plants was attributed to reduced allocation of tree reserves toward vegetative growth. As a result, assimilate availability was not limited, unlike in untreated control trees, where excessive vegetative growth competed for assimilates.

Effect of Fertilizer Dose (F):

The effect of different fertilizer dose on number of panicles per tree was found to be significant. The maximum number of panicles per tree (588.94) was recorded under F 2 (50% of N, 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the minimum number of panicles per tree (554.94) was recorded under F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August). Fouad et al. (2003) [5] reported that increasing potassium levels in combination with balanced nitrogen and phosphorus significantly increased the number of panicles per tree in mango. Interaction Effect (DxF): The interaction effect of application of paclobutrazol and fertilizer Dose on number of panicles per tree was found to be non-significant.

Effect of Paclobutrazol (D):

The length of panicle of mango was significantly increased by the application of paclobutrazol. The maximum length of panicle (32.05 cm) was recorded with the dose of paclobutrazol @ 2.5 ml a.i. (D 4 ) followed by (29.64 cm) was recorded @ 2.0 ml a.i. (D 3 ) and (28.77 cm) was recorded @ 1.5 ml a.i. (D 2 ). The minimum length of panicle (27.64 cm) was recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). Application of paclobutrazol influenced panicle length by suppressing excessive vegetative growth through inhibition of gibberellin biosynthesis. The reduced vegetative growth favoured reproductive development and resulted in changes in panicle elongation. This observation is in agreement with the earlier findings of paclobutrazol influence on the length of panicle by Desai, 1994) [6] , Zora et al. (2000) [7] , Golla et al. (2017) [8] , Subbaiah et al. (2017) [9] and Sarkar and Rahim (2018) in Sarvade et al. (2024) [10] Effect of Fertilizer Dose (F): The effect of different dose of fertilizer on length of panicle was found to be significant. The maximum length of panicle (31.30 cm) was recorded with fertilizer dose F 2 (50% of N, 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the minimum length of panicle (27.75 cm) was recorded with the dose of fertilizer F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August. The higher nutrient levels enhanced the development of longer and more robust panicles, which are critical for increasing the number of flowers and potential fruit set. This observation is in agreement with the earlier findings of dose of fertilizer influence on the length of panicle by Sharma et al. (2000) [11] , Vala et al. (2020) [12] and Azam et al. (2022) [13] Interaction Effect (DxF): The interaction effect of application of paclobutrazol and fertilizer dose on length of panicle was found to be non-significant.

Yield parameters

Effect of Paclobutrazol (D):

The effect of different doses of paclobutrazol on weight of fruit differed significantly. The maximum weight of fruit (280.72 g) was recorded with the dose of paclobutrazol @ 2.5 ml a.i. (D 4 ) which was statistically at par with D 3 (262.58 g) with the dose of paclobutrazol @ 2.0 ml a.i. followed by (240.14 g) was recorded @ 1.5 ml a.i. (D 2 ). The minimum weight of fruit (225.10 g) was recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). Paclobutrazol treatment often results in thicker leaves with increased chlorophyll content, which enhances photosynthetic efficiency. The improved photosynthetic capacity leads to greater production of sugars and other carbohydrates, providing additional assimilates for fruit development and thereby contributing to increased fruit weight. This observation is in agreement with the earlier findings of paclobutrazol influence on of fruit weight Hasan et al. (2013) [14] and Reddy et al. (2013) [15] .

Effect of Fertilizer Dose (F):

The effect of different dose of fertilizer on weight of fruit differed significantly. The maximum weight of fruit (271.52 g) was recorded with fertilizer dose F 2 (50% of N and 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the minimum weight of fruit (232.74 g) was recorded with the dose of fertilizer F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August). The combined application of N, P, and K ensures balanced nutrition, leading to improved photosynthetic efficiency, enhanced assimilate production and translocation, better nutrient uptake, increased cell division and enlargement, and greater accumulation of carbohydrates in the fruits (Singh et al., 1977) [16] Interaction Effect (DxF): The interaction effect of application of paclobutrazol and fertilizer dose on weight of fruit was found to be nonsignificant.

Effect of Paclobutrazol (D)

The effect of different dose of paclobutrazol on fruit yield per tree differed significantly. The maximum fruit yield per tree (98.89 kg) was recorded with the dose of paclobutrazol @ 2.5 ml a.i. (D 4 ) followed by (84.70 kg) was recorded @ 2.0 ml a.i. (D 3 ) and (61.02 kg) was recorded @ 1.5 ml a.i. (D 2 ). The minimum fruit yield per tree (55.07 kg) was recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). As the Paclobutrazol significantly increases the fruit set % in mango by suppressing excessive vegetative growth and promoting reproductive development. This ultimately leads to increase in yield per tree. This observation is in agreement with the earlier findings of paclobutrazol influence on yield per tree Srilatha et al. (2015) [17] , Subbaiah et al. (2017) [9] and Ravindra et al. (2020) [18] . Effect of Fertilizer Dose (F): The effect of different dose of fertilizer on fruit yield per tree differed significantly. The maximum fruit yield per tree (83.94 kg) was recorded with fertilizer dose F 2 (50% of N, 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the minimum fruit yield per tree (65.90 kg) was recorded with the dose of fertilizer F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August). Thus, the yield was also highest under this treatment, due to better absorption and accumulation of nutrients by crop at higher fertilizer rates (Rumpel et al., 2003) [19] . Interaction Effect (DxF): The interaction effect of application of paclobutrazol and fertilizer dose on yield per tree was found to be nonsignificant.

Effect of Paclobutrazol (D):

The effect of different doses of paclobutrazol on fruit yield per hectare differed significantly. The maximum fruit yield per hectare (9.89 t/ha) was recorded with the dose of paclobutrazol @ 2.5 ml a.i. (D 4 ) followed by (8.47 t/ha) was recorded @ 2.0 ml a.i. (D 3 ) and (6.10 t/ha) was recorded @ 1.5 ml a.i. (D 2 ). The minimum fruit yield per hectare (5.51 t/ha) was recorded in the control treatment (D 1: 0 ml a.i. of paclobutrazol). Paclobutrazol application influenced yield per tree by regulating vegetative growth and promoting reproductive development. The reduction in excessive vegetative growth favoured flowering, fruit set and fruit retention, which ultimately contributed to higher yield per tree. This observation is in agreement with the earlier findings of paclobutrazol influence on yield per tree Srilatha et al. (2015) [17] , Subbaiah et al. (2017) [9] and Ravindra et al. (2020) [18] . Effect of Fertilizer Dose (F): The effect of different dose of fertilizer on fruit yield per hectare differed significantly. The fruit yield per hectare of mango was significantly increased by fertilizer application. The maximum fruit yield per tree (8.39 t/ha) was recorded with fertilizer dose F 2 (50% of N, 50% of K and 100% of P in the last week of June and 50% of N and 50% of K in the month of August), whereas the minimum fruit yield per tree (6.59 t/ha) was recorded with the dose of fertilizer F 1 (50% of NPK in the last week of June and 50% of NPK in the last week of August). Thus, subsequently the yield was also highest under this treatment, due to better absorption and accumulation of nutrients by crop at higher fertilizer rates (Rumpel et al., 2003) [19] .

Conclusion

The study revealed that paclobutrazol and fertilizer application significantly influenced flowering, panicle development, fruit weight and yield of mango cv. Kesar. Paclobutrazol @ 2.5 ml a.i. (D 4 ) recorded superior performance, while fertilizer schedule F 2 (50% of NK and 100% of P in the last week of June and 50% of N and 50% of K in month of August) resulted in earlier flowering, better panicle development, higher fruit weight and yield. Overall, the application of paclobutrazol @ 2.5 ml a.i. along with F 2 fertilizer schedule was found effective for improving flowering and productivity of mango cv. Kesar under the conditions of the present study.

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19. How to cite this article: Amminabhavi PM, Shinde V, Kamble V, Puri A, SS O. Effect of application of paclobutrazol and fertilizer dose on infloresence and yield of mango (Mangifera indica L.) Cv. Kesar. International Journal of Research in Agronomy. 2026;9(10):264-268. doi: https://www.doi.org/10.33545/2618060