PROBÍRKA PLŮDKŮ JABLONÍ ODRŮDY ‘GOLDEN DELICIOUS’ INDUKOVANÁ POMOCÍ CÍLENÝCH OŠETŘENÍ ČÁSTÍ KORUNY [FRUIT THINNING IN APPLE VARIETY ‘GOLDEN DELICIOUS’ INDUCED BY AIMED APPLICATIONS ON PART OF THE CROWN ]

Abstract

Chemical thinning is currently the most utilized way of crop load regulation in apples to attain desired marketable fruit size. In intensive densely planted orchards, the lower part of crowns is more shaded and its response to chemical thinning can be strong. It often leads to very low fruit set in lower part of crowns and yield losses. Objective of our trial was to find out the response of the trees when thinning agents were applied on whole or only on an upper part of the crown. The trial took place in production orchard of variety ‘Golden Delicious’. Following thinning agents were used: benzyladenine, 1-naphthaleneacetic acid, and metamitron. Thinning and yield parameters were assessed. Fruit number of various fruit sizes was assessed separately for lower and higher part of the crown. The strongest thinning efficacy was recorded for application of metamitron on whole crown. This treatment caused the strongest thinning in lower part of crown and the strongest overall yield reduction. Application of metamitron only on upper part of crown avoid strong thinning in lower part of crown and ensured standard thinning in upper part of crown. Other treatments where only the upper part of the crowns were treated showed similar effects. Applied thinning agents thus showed spatially specific thinning action. Aimed application on upper part of crown proved to be useful and promising for practical use in intensive densely planted orchards.

Keywords

• malus sp.
• yield
• fruit size
• benzyladenine
• 1-naphthaleneacetic acid
• metamitron