Influence of phosphorous and potassium nutrition on growth, yield and fruit quality of Gala Mast apple

Present study was conducted at the experimental field of Division of Fruit Science, SKUAST-Kashmir, Shalimar Campus, Srinagar (Jammu and Kashmir) on four-year-old Gala Mast apple grafted on MM106 rootstock under high density plantation (3m x 3m) to standardize the optimum dose of phosphorous and potassium. Sixteen treatment combinations consisting of four levels each of phosphorous (25 g, 50 g, 75 g and 100 g/tree) and potassium (150 g, 200 g, 250 g and 300 g/tree) were tested. Maximum increase in tree height (55.89 cm), tree girth (2.31 cm), annual shoot extension (47.13 cm), leaf area (42.00 cm²), fruit length (6.52 cm), fruit diameter (7.31 cm), fruit weight (168.26 g), fruit volume (185.48 cm³), yield (6.85 kg/tree), total soluble solids (15.85^oB), total sugars (13.17%), ascorbic acid (5.89 mg/100 g) and anthocyanin content (9.27 mg/100 g) were observed with the application of phosphorous @ 100 g + potassium @ 300 g. Highest fruit firmness (9.81 kg/cm²) was recorded when phosphorous @ 100 g + potassium @ 150 g was applied, whereas minimum acidity (0.197%) and maximum TSS/acid (76.47) ratio was recorded with the application of phosphorous @ 25 g + potassium @ 300 g. Therefore, it can be concluded that phosphorous @ 100 g/tree in combination with potassium @ 300 g/tree proved to be most economical and effective in improving growth, yield and quality of apple cv. Gala Mast.