Effect of prohexadione calcium and chlormequat chloride on growth, yield and fruit quality of pear under high density planting

The present experiment was conducted to evaluate the effect of plant bioregulators (PBRs) on vegetative growth, fruit yield and quality of quality of pear cv. Patharnakh trained on Y-trellis system. The foliar applications of prohexadione calcium (100, 200 and 400 ppm) and chlormequat chloride (250, 500 and 1000 ppm) was done on eight-years-old trees at 10 days after full bloom. The control trees were sprayed with water only. Observations on vegetative growth, fruit number/plant, fruit size, fruit quality and leaf nutrients were recorded. Reduction in pruning wood weight without any effect on return bloom was observed with different PBR treatments. Prohexadione calcium (400 ppm) was found most effective in reducing shoot number (70) and internodal length (4.18 cm). This treatment also increased fruit number (83 per tree), fruit size (8.04 cm × 7.51 cm), TSS content (12.33 °Brix), fruit frmness (62.94 N), and reducing sugars content (7.00%); however, the titratable acidity was not affected. As compared to control, fruit yield of pear tree was signifcantly improved (~35%) with the Pro-Ca 400 or 200 ppm treatments. Similarly, higher dose of chlormequat chloride (500 or 1000 ppm) signifcantly reduced the shoot number and intermodal length, and increased fruit yield as compared to control. The PBR treatments reduced the leaf nitrogen content but increased leaf phosphorus and potassium levels.