Effect of Growth Regulating Substances on the Control of Flowering and Fruit Setting in Sweet Cherry Cultivar Black Heart

The experiments conducted on low fruit setting sweet cherry cultivar Black Heart at the orchard of Regional Fruit Research Station, Mashobra, (H.P.) with growth regulators revealed that 8.83 per cent increased fruit set over control was obtained with NAA at 100 ppm concentration in 1966 and 28.67 and 27.83 per cent fruit retention was observed at two weeks after pea stage at 60 ppm NAA during 1967 and 1968. At maturity NAA or GA showed no significant effect on fruit retention or on the average weight, size and volume of fruit and seed weight. Gibberel-lic acid at 100 ppm delayed the flower bud opening in the next season of growth, which avoided frost damage of flowers and showed an increased fruit set in the year 1969 and 1970.