In 1990, 15-yr-old `Smoothee Golden Delicious' trees on M.9, M.9/MM.111, and MM.111 were used. On each of 4 trees per rootstock, 3 branches (1.0-1.7 cm dia) were selected. On 7 June (45 DAFB), crop loads were adjusted to 3, 5, or 7 fruit per cm2 branch cross sectional area (BXSA), and each branch was girdled. On 6 Sept all fruit were harvested; fruit weight, ground color, percent blush, soluble solids, starch, and firmness were regressed against crop load. Each was negatively related to crop load, most strongly for soluble solids, ground color and blush. Rootstock influenced several factors and some interaction with crop load occurred.
In 1991, heavily cropping 10-yr-old trees of Empire/M.7A were used. One each of 7 trees, branches (1.2-2.0 cm dia) were thinned to 4, 8, or 12 fruit/cm2 BXSA on 5 June (40 DAFB). One branch per crop load per tree was girdled on 5 June. On 29 Sept fruit were harvested for evaluation. ANOVA indicated significant interactions between crop load and girdling for fruit weight, firmness, soluble solids and starch. Each showed a significant negative linear regression with crop load on girdled branches; on ungirdled branches none of the regressions were significant.