Applications of N-(2-chloro-4-pyridyl)-N’-phenylurea (CPPU) can increase blueberry (
Vaccinium corymbosum
L.) yield and fruit size, but their impact on postharvest is unknown. We studied repeated CPPU applications effects on yield and quality (harvest, postharvest), over 2 yr on mature ‘Duke’ plants in South-Central Chile. The first year, 5 or 10 mL L
-1 CPPU was applied at 3, 10, and/or 17 d after full bloom (DAFB) plus a non-sprayed control. The second year, 5 or 10 mL L
-1 CPPU were sprayed 10 and 17 DAFB plus a control. The first year, only 10 mL L
-1 CPPU sprayed 3+17 DAFB increased yield (32.5% > control); 10 mL L
-1 CPPU applied 10 or 3+17 DAFB had highest fruit diameter; and 10 mL L
-1 CPPU at 17 DAFB or at 3+10+17 DAFB had highest soluble solids. Overall, 10 mL L
-1 CPPU applied 3+17 DAFB, was the best treatment for year one, since it increased fruit yield and diameter, while soluble solids and postharvest weight loss were similar to control. The second year, 10 mL L
-1 CPPU reduced fruit coloration (blue color coverage index: BCCI) and soluble solids, but not firmness at harvest. This rate increased berry weight (24.2%) and fruit wax (59% > wax coverage index: WCI) at harvest. Harvest and postharvest WCI increased consistently as CPPU rate increased. CPPU reduced fruit rotting (15% at 45+5 evaluation). During storage, CPPU-treated-fruit had a slower decrease in firmness (30.5% < control at 30+1), but no difference at 30+5. CPPU-treated-fruit usually had higher post harvest soluble solids. Ten mL L
-1 CPPU retarded color evolution at harvest and at 30+1, but not at 30+5, 40+1 or 40+5.
