Effects of Shoot Heading on Three Canopy Vase Forms of Apricot Trees (Armeniaca vulgaris Lam.)

The study was carried out in the Przybroda experimental orchard near Poznań, Poland, using the three apricot cultivars: Goldrich, Hargrand and Sirena. The trees were trained to three canopy vase forms. Every year, in spring, shortly after the blooming period, apricot tree shoots were shortened by one half, or by one third of their length. The control trees were not shortened. The influence of the shortening of the shoots on tree growth, morphology of fruit bearing zone, flower bud setting, and tree yielding was studied. Trees with shoots shortened by one half of their length developed a greater number of branched shoots than the control trees, but, at the same time, they developed less spurs. The best yielding results were obtained from the ‘Sirena’ trees, while the lowest yielding results were obtained from ‘Goldrich’. Trees with a vase canopy form, with 7-9 limbs and branches, and with shoots shortened by one third of their length, yielded better than the trees of the two other canopy forms