Effects of summer pruning on vegetative growth, fruit quality and carbohydrates of 'Regina' and 'Kordia' sweet cherry trees on 'Gisela 5'

Five-year-old sweet cherry trees of 'Kordia' and 'Regina' were summer pruned in 2003, 2004 and 2005. Pruning in 2003 consisted of three treatments of heading new shoots (0, 33.3 and 66.6% of the length of annual shoots was removed), in 2004 of pruning like in 2003 and by thinning vigorous branches, and in 2005 of thinning of vigorous branches only. Summer pruning positively influenced vegetative growth and fruit quality of 'Kordia' and 'Regina' on 'Gisela 5'and had no negative effect on the content of soluble carbohydrates in the dormant shoots. Pruning to remove some major branches promoted better fruit quality than did heading of annual shoots. Control trees had a similar yield and yield efficiency as pruned trees but lower fruit weight and quality. Trees of 'Kordia' and 'Regina' on 'Gisela 5' should be pruned annually to avoid the development of blind wood and to balance canopy F:LA for high sweet cherry fruit quality. Trees of 'Regina' should be pruned more strongly than those of 'Kordia'.