ISHS Acta Horticulturae 517: XXV International Horticultural Congress, Part 7: Quality of Horticultural Products
CONTROL STRATEGIES FOR DIFFERENT BITTER PIT INCIDENCES IN BRAEBURN APPLES |
| Authors: | J.B. Retamales, V.P. Lepe |
| Keywords: | calcium, magnesium, mineral nutrition, physiological disorders |
| Abstract:
Bitter pit (BP), the main physiological disorder of pome fruits, is linked to calcium (Ca) and magnesium (Mg) nutrition, and needs to be predicted and controlled. Effective BP prediction, based on fruit Mg infiltration, would provide a 3-week window before harvest to spray Ca and correct BP, but the effectiveness of these sprays is unknown. In a factorial experiment using 3-year-old Braeburn/seedling trees, various crop loads (low-LC, 55 fruits/tree; medium-MC, 70 fruits/tree and high-HC, 150 fruits/tree) were established by hand thinning 57 days after petal fall; this provided different BP potentials (High, HBP; Medium, MBP; and low, LBP), respectively. Trees in the various BP potentials, received either: no Ca during the season (control), 2 or 4 sprays of CaCl2 in the 3 weeks before harvest. Results show that: 1.- Crop load affected BP levels (50% in HC vs. 75% in LC, for control plants), 2.- For all BP potentials, Ca sprays effectively reduced BP incidence (40 to 73% less BP); BP control increased with more Ca sprays, and 3.- A significant reduction in BP incidence can only be reached through an integrated approach that combines exogenous Ca sprays with cultural practices (in this case, crop load). | |
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