Climate influence on abscission pattern and efficacy of chemical thinners in nectarine cv. may fire

The present investigations were subjected to nine different treatments viz. at Naphthaleneacetic acid40 and 60 ppm; Ethrel at 200 and 300 ppm applied one and two week after petal fall and controlon 12-year old trees of nectarine cultivar May Fire, At both locations, treatment with NAA at 40 ppm when applied two weeks after petal fall resulted insignificantly higher thinning percentage.NAA and ethrel when applied two week after petal fall induced early fruit than applied one week after petal fall.NAA at 40 ppm and Ethrel at 300 ppm when applied two weeks after petal fall caused complete degeneration of cells in pith, vascular and cortex regionson the 3^d day (at 20.5°C/13°C maximum and minimum temp. and 60.3% RH).In control stimulation of cell disintegration could not be examined in any region during the 15days of observing period.