EFFECT OF FOLIAR BORON APPLICATION ON GROWTH, REPRODUCTION, AND OIL QUALITY OF OLIVE TREES CONDUCTED UNDER A HIGH DENSITY PLANTING SYSTEM

Boron (B) foliar treatments (300 mg L-1 as Solubor DF) were applied at two different dates in 2006 and 2007, prior to flowering and just after fruit set, on olive (Olea europaea L.) trees with no visual symptoms of B deficiency. Leaf B level increased after the first application as compared to control (-B). After July treatment, leaf B levels in -B and + B treated trees increased when compared to the first sampling date. Foliar B application did not significantly affect vegetative growth in either year. During the first year of study (considered as an "on year"), B application had no significant effect on several phenological characteristics including fruit set, yield oil contents and oil quality. In the second year ("off year"), B sprays improved blooming rate, which increased from 20% in -B to 30% in + B treated trees, and olive yield, which increased by 27% in response to B.