Control of shoot growth of peach and nectarine trees with paclobutrazol

Abstract

SummaryExperiments were carried-out on ‘Crimson Gold’ nectarine and ‘Redhaven’ peach to investigate effects of paclobutrazol on tree growth. This growth regulator strongly inhibits vegetative growth of these cultivars by reducing the number and length of internodes per shoot. Soil applications in early spring reduced shoot extension growth in ‘Crimson Gold’ trees, the effect increasing linearly with the amount applied. Autumn applications to the soil were less effective in this cultivar, but a significant inhibition of shoot growth has been observed in ‘Redhaven’. Foliar sprays also controlled shoot growth when concentrations of 250 ppm were applied on four occasions. No differences in yield were observed, although increases of mean fruit weight were found when paclobutrazol was applied to the soil in early spring. In the year after applying paclobutrazol, the trees previously treated grew more than the untreated controls.