Performance and oil quality of 'Arbequina' and four Italian olive cultivars under super high density hedgerow planting system cultivated in central Italy.

Super high density (SHD) olive, has been introduced in Italy, mainly in the southern regions (flat areas of Apulia and Sicily), in the middle of 2000s, using only three cultivars of low vigour: ‘Arbequina’, ‘Arbosana’ and ‘Koroneiki’. Since the limited cultivar choice is still considered one of the main issue for SHD in central Italy, a comparative trial was set up in 2006 to evaluate the suitability of 4 Italian olive cultivars to a planting density of 1667 trees ha–1, Vegetative vigour, productivity and oil quality were evaluated for four local cultivars (‘Frantoio’, ‘Leccino’, ‘Maurino’ and ‘Moraiolo’) in comparison with the standard ‘Arbequina’in a SHD orchard. ‘Frantoio’ and ‘Leccino’ were more vigorous than ‘Arbequina’ and ‘Maurino’; the most precocious were ‘Arbequina’ and ‘Maurino’, and the most delayed ‘Frantoio’. After eight years form plantation, ‘Arbequina’ and ‘Maurino’ provided significantly higher accumulated yield when compared to ‘Leccino’. Considering all the vegetative tree characteristics (canopy volume, trunk section area and removed wood by pruning) the most vigorous cultivars were ‘Frantoio’ and ‘Leccino’. The crop efficiency of ‘Maurino’ was similar to that of ‘Arbequina’ and higher than those of the other 3 Italian cultivars. Concerning the oil quality the highest phenols content was recorded in ‘Frantoio’ and ‘Leccino’ oil; the lowest in ‘Arbequina’ oil. On the contrary ‘Frantoio’, ‘Leccino’ and ‘Moraiolo’ had the highest oleic acid contents while ‘Arbequina’ and ‘Maurino’ had similar values. Polyunsaturated fatty acid content was significantly higher in olive oil from ‘Maurino’. To conclude we can say that ‘Maurino’, showing low vegetative vigour and compact growth, early and high yield, adaptation to mechanization, good oil quality and shelf life, resulted to be the most suitable cultivar for SHD system in this trial.