Effect of shading and paclobutrazol during dormancy on apricot (Prunus armeniaca) productivity

Abstract

Shading all or parts of trees and the application of paclobutrazol during the dormant season, were studied as strategies to improve apricot (Prunus armeniaca) fruitfulness. Shading the whole tree reduced flower bud abscission, probably because of a decreased level of gibberellins resulting from a reduction of temperature in the shaded trees. Partial shading of individual branches did not reduce percentage of flower bud abscission compared to unshaded branches. Shading also accelerated ovule maturity at anthesis. These results show the importance of solar radiation on the basic structure of the tree (the trunk and primary branches) for the productive behaviour of apricot. Paclobutrazol treatments did not significantly influence flower bud drop and fruit set on apricot during the 2 years of the study. However, these treatments slightly accelerated ovule maturity at anthesis, probably because of the reduction in the level of gibberellins.