Effects of apple branch girdling on retention and quality of fruit and vegetative growth

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Virginia Tech


In 1992, branches on ‘Triple Red Delicious’/M.7 were girdled. A factorial arrangement of girdling treatments (control, 9-mm girdle + uncovered, 9-mm girdle + electric tape, 9-mm girdle + TreeKote), and timings (0, 15, 30, 60, 90 days after full bloom (DAFB)) was used. With ‘Golden Delicious’/M.7, branch treatments were control, scored, and 6-mm, 9-mm, 12-mm electric-tape-covered girdles, each applied at 0, 15, 30, and 60 DAFB. In 1993, treatments on both cultivars were control, 9-mm uncovered girdle, and pruning saw wound. Each was applied at 0, 7, 14, and 21 DAFB. Each girdle was a complete ring of bark; pruning saw wound was removal of bark using a pruning saw; scoring was a knife cut through the bark.

In 1992, the two cultivars responded similarly to girdling. Effects were greatest with treatments at 0 to 30 DAFB and included increased fruit set or retention, temporary suppression of vegetative growth (except watersprouts), and increased levels of soluble solids in the fruit. Treatments affected starch levels in the fruit and flesh firmness, but these effects were variable.

In 1993, the two cultivars responded similarly to the main effects of girdling, which caused increased crop density and yield efficiency. Girdling increased mean apple diameter, weight, and soluble solids on ‘Triple Red Delicious’/M.7 branches. Fruit diameter was reduced on ‘Golden Delicious’/M.7 branches. Girdling affected flesh firmness in both cultivars, but these results were variable.