Effect of growth regulators on water relations and fruit yield of rain-fed sapota (Achras sapota).

Abstract: A study was conducted to determine the effect of paclobutrazol, Cycocel [chlormequat] and Chamatkar [mepiquat chloride] on the water relations and fruit yield of sapota (A. sapota [Manilkara zapota]) cv. Kalipatti at the Horticultural Research Station of the University of Bangalore, Karnataka, India. Treatments comprised 250, 500 and 750 ppm Cycocel; 1000, 2000 and 3000 ppm Chamatkar; 1.25, 2.50 and 5.00 g paclobutrazol; and control (water spray or no spray). Paclobutrazol, Cycocel and Chamatkar were effective in improving water relations and fruit yield of sapota. Paclobutrazol at 5 g was the most effective. All growth regulators increased the relative water content and decreased the transpiration, but the most pronounced effect was with 5 g paclobutrazol. None of the growth regulators affected the stomatal resistance. The growth regulator treatments affected the second year fruit yield, unlike the first year fruit yield. The highest fruit yield on the second year (56.3 kg/plant) was obtained with 5 g paclob