Effect of PGRs application on ‘mrig-bahar’ of guava under sub-Himalayan subtropical growing conditions
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Date
2024-02-08
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College of Horticulture and Forestry Dr YSP UHF, Neri, Hamirpur(H.P.)
Abstract
The studies on the “Effect of PGRs application on ‘mrig-bahar’ of guava under sub-Himalayan subtropical growing conditions” were conducted in the experimental orchard of the Department of Fruit Science, College of Horticulture and Forestry, Neri, Hamirpur during the year 2022 and 2023 with the aim to improve the yield and quality of guava cv. L-49 raised under a high-density system of planting (2x1m). An experiment with three-factor treatments (benzyladenine (BA) foliar application at fruit set, paclobutrazol (PBZ) soil applications during July and August and ethrel at the onset of fruit maturity) was laid out in RBD factorial layout with binary treatments of BA- 0, 50 ppm; PBZ- 0, 10 g/plant and ethrel- 0, 500 ppm. The combined application of BA foliar spray at fruit set and PBZ
soil drenching during July and August resulted in the minimum fruit drop of 39.3 % which was significantly lower than control. Ethrel foliar application at the onset of fruit maturity reduced the time from fruit set to harvest by around 3 days. The fruit physical parameters, like size (6.3 cm), weight (137.0 g), volume (124.0 cm3), specific gravity (1.07), and yield (4.21 kg) were obtained better with a conjoint application of BA, PBZ, and ethrel. However, ethrel alone exhibited better fruit firmness. Ethrel and PBZ applications significantly improved fruit surface yellowness index, with the highest index value of 89.8 recorded under this treatment combination. Biochemical fruit quality parameters such as TSS (13.6 ⁰B) and total sugars (9.3%) were highest with the combination of PBZ and ethrel, while individual PBZ application increased ascorbic acid and pectin content. PBZ application exerted control over vegetative growth parameters and resulted in higher leaf carbohydrate and phenol content. Overall, it has been concluded that the soil application of PBZ at 10 g/plant during July and August significantly improves fruit quality and yield parameters while controlling vegetative growth, also. Conjoint application of BA at fruit set @ 50 ppm foliar spray, PBZ soil application @ 10 g/plant (2 applications in July and August) and ethrel spray @ 500 ppm at the onset of maturity was the best treatment combination for early harvest of fruit with better colour, firmness and other quality fruit parameters.