Leaf pinching and phytohormones - two important components for the branching induction on sweet cherry

Abstract

The promising branching agent cyclanilide [1-(2,4-dichlorophenylaminocarbonyl)-cyclopropane carboxylic acid] is not permitted in the EU and the low vigour rootstocks preferred by growers make the branching of young sweet cherry (Prunus avium) trees difficult in the temperate zone production regions. To increase the number and length of new branches (“feathers”) on such trees, chemical (6-benzyladenine [BA], gibberellic acid [GA<sub>4/7</sub>]), mechanical (leaf pinching, summer notching) and various combined treatments were tested from 2015–2018. The numbers of feathers divided into three different lengths (1–10 cm, 10–30 cm and > 30 cm) were assessed as the main indicator of quality, supplemented with other morphological characteristics. Summer notching induced an insufficient number of feathers and led to some negative effects on the trees. The number of feathers from BA or BA with GA<sub>4/7</sub> treatment also was insufficient. The effect of pinching alone was variable. The number of all feathers generally was highest when pinching was combined with BA, regardless of the year or cultivar.