INFLUENCE OF SUMMER PRUNING ON GROWTH, FRUIT SET AND FRUIT QUALITY OF ANNA APPLE TREES

The effect of summer pruning and shoot topping in April, May or June on Anna apple (Malus domestics Borkh.) trees/M.M. 106 were stud­ied through 1995/96 seasons to investigate the response on growth rate, leaf mineral content, productivity, fruit characters, and fruit mineral content. The growth rate of shoot length, number of shoots, leaf area, and dry matter increased after summer pruning and shoot topping_ Also, the leaves of pruned trees accumulated much more nutrient elements (N, P, K). Productivity parameters (percentage of fruit set, number of spurs in one meter of a main scafold, and spurs' number per pruned tree apparently increased with pruning treatments. Pre-harvest fruit abscis­sion significantly decreased, may be as a result of raising the level of po­tassium in both leaf and fruit Although the number of mature fruits per tree decreased, fruit quality characters (fruit weight, volume, fimness, total soluble solids (TSS), acidity/and TSS/acid ratio), and fruit nutrient elements content (N,P,K, Ca) increased. The influence of summer prun­ing was found to be linearly related to its severity (the length of re­moved shoot). However, pruning in May was better than in April or June.