Effects of Plant Growth Regulators on Fruit Set and Yield of Pomegranate Cv. Bhagwa

An experiment was conducted during 2014-15 at Hiriyur, Chitradurga district to study the response of various plant growth regulators at different concentrations namely, NAA (40, 50, 60 ppm) and GA3 (40, 50, 60 ppm) on fruit set and yield of pomegranate cv. Bhagwa. The results indicated that NAA 40 ppm was found effective in increasing number of fruits per tree (62.44), fruit length (8.66 cm), fruit diameter (8.71 cm), fruit weight (262.23 g), fruit volume (255.44 ml), TSS (16.76 ̊B), total sugars (15.58 %), reducing sugars (13.83 %), non-reducing sugars(1.75 %) against control. Introduction: Pomegranate (Punica granatum L.) is one of the oldest known edible fruits and is capable of growing in different agro-climatic conditions ranging from the tropical to sub-tropical (Levin, 2006; Jalikop, 2007). Though, it is native of Iran but cultivated extensively in Mediterranean and central Asian countries. It is highly suitable for growing under arid and semiarid regions due to its versatile adaptability, hardy nature, low cost maintenance and high returns. In recent past its wide significance in health, nutrition and livelihood security has been recognized which resulted in heavy demand for fruit consumption not only in India but throughout the globe. In India, pomegranate is commercially cultivated in Maharashtra, Karnataka and Andhra Pradesh and the most important cultivar in this pomegranate belt is ‘Bhagwa’ which covers around 80% area under pomegranate in Maharashtra. Since last two decades, its cultivation has popularized in arid and semi-arid regions of India, not only because of its sweet acidic taste, precocious bearing and better shelf-life but as a remunerative crop as well. Among various arid fruits, pomegranate occupies second largest area after ber. The importance of synthetic plant growth regulators in achieving higher yield and better quality of horticultural crop has been well recognized in recent time. Plant growth regulators have given encouraging results in case of pomegranate fruit crop. However, practically, there has been very little work done on use of plant growth regulators in pomegranate crop. Hence, the objective was to study the effects of plant growth regulators on the fruit set and yield of pomegranate cv. Bhagwa. Materials and Methods: The experiment was conducted at farmers field Hosayalanadu, Hiriyur, Chitradurga district during 2014-15 on Bhagwa planted at a spacing of 12ft ×10ft.The experimental trees were four years old. Totally, 7 different treatments of NAA and GA3 at different concentrations were sprayed in pomegranate orchard with three replications. The experiment was laid out in a Randomized Block Design. The growth regulators were sparyed after full bloom. Rest of the cultivation practices were as per the university package of practice. Three plants were sprayed in each treatment. The days taken for fruit set was calculated by taking the observation from the day of spraying to till fruit set. The yield was recorded at the time of harvest and expressed in terms of kg/plant. The physiological loss in weight was recorded by taking readings at 4 days intervals after harvest. The data recorded was analyzed using the stastistical procedures as described by Fisher and Yates (1963). Results and Discussion: The data pertaining to the number of days taken for fruit set as influenced by different growth regulators and their concentrations are furnished in Table 1. The number of days taken for fruit set in relation to different growth regulators was found to be non-significant. Among the different treatments, the plants treated with NAA 40 ppm showed minimum days (37.55) taken for fruit set followed by NAA 50 ppm (38.22) as against control (40.66). The data revealed that the different treatments had significant effect on yield parameters (Table 1). The maximum number of fruits per plant (62.44), yield in (16.45 kg/plant and 15232.70 kg/ha) was recorded with application of NAA 40 ppm. This may be due to the better physiology of developing fruits in terms of better supply of water, nutrients and other compounds vital for their proper growth and development which resulted in improved size and ultimately greater yield as compared to GA3. Beneficial effects of NAA and GA3 were recorded by Ghosh et al. (2009) in cv. Ruby, Adi and Prasad (2012) in cv. Ganesh and Goswami et al. (2013) in cv. Sindhuri of pomegranate. The data (Table 1) indicate that application of various chemicals significantly improved the physical parameters of the fruit. Maximum fruit length(8.66 cm), fruit diameter (8.71 cm), fruit weight (262.23 g) and fruit volume (255.44 ml) was recorded with foliar spray of 40 ppm NAA. This may be due to immediate absorption of auxins, which increased the endogenous auxin level that resulted in cell elongation which accelerated the development of fruits. Beneficial effects of NAA 25 ppm and GA3 10 ppm were also recorded by Ghosh et al. (2009) for all the parameters in pomegranate. Significant increase in fruit weight was observed by Hussein et al. (1994) in pomegranate by using NAA 20 ppm. Treatments Days taken for fruit set Yield Fruit Number Kg/ plant Kg/ha Length (cm) Diameter (cm) Weight (g) Volume (ml) T1-Control (Water spray) 40.66 45.00 8.14 7540.73 4.48 5.01 181.00 178.32 T2-NAA 40 ppm 37.55 62.44 16.45 15232.70 8.66 8.71 262.23 255.44 T3-NAA 50 ppm 38.22 60.11 15.06 13942.47 8.42 8.46 250.43 249.85