INFLUENCE OF GROWTH REGULATOR APPLICATION ON FROST RESISTANCE OF FRUIT TREE SHOOTS, SPURS, FLOWERS AND FRUITLETS

In 1983 and 1984, seven experiments were carried out on the influence of growth regulators applied to leaves and to soil on the resistance to low temperature of shoots, spurs, flowers and fruitlets of apple, peach and cherry trees.

Paclobutrazol^1/ and DEPEG^2/ folliage and soil applications did not show any positive effects on the change of frost resistance level of one-year-old peach shoots.
Spraying with Paclobutrazol increased the frost resistance of Azwellspur and Melrose spurs, as well as Alar decreased the frost resistance of one-year-old shoots of Cortland apple cultivars.
In experiment with cherries, spraying with Paclobutrazol in 1000 ppm concentration increased the resistance to low temperature of one-year-old cherry shoots.
Spraying of apple, cherry and peach trees with DEPEG in 1000 and 2000 ppm in full bloom period contributed to reduce injuries of flowers and fruitlets caused by low temperatures, whereas spraying with Paclobutrazol in 1000 ppm concentration decreased frost resistance of fruit tree flowers and fruitlets.

II Symposium on Winter Hardiness in Woody Perennials

T. Holubowicz

https://doi.org/10.17660/ActaHortic.1985.168.14