Promising Olive Cultivars for Oil Production in Hawaii

Abstract

To determine promising olive (Olea europaea) cultivars for oil production in Hawaii, seven trees each of 10 cultivars (Arbequina, Arbosana, Coratina, Frantoio, Koroneiki, Leccino, Mission, Moraiolo, Pendolino, and Taggiasca) were planted in Feb. and July 2011 at the Lalamilo Experiment station on Hawaii Island (lat. 20.0176°N, long. 155.6827°W, elevation 2700 ft). In addition, two trees each of these 10 cultivars were planted in June 2011, with the exception of Arbequina, which was planted in July 2012, at the Maui Agricultural Research Center in Kula, Maui (lat. 20.7564°N, long. 156.3289°W, elevation 3100 ft). At Lalamilo, after ≈2 years of growth in the field (2013), three cultivars of olives (Arbequina, Arbosana, and Koroneiki) flowered, fruited, and produced oil yields of greater than 20%. These same cultivars flowered and fruited in 2014 and 2015. There was no significant difference among cultivars in fresh weight fruit yield averaged over 2 years (2013 and 2014), ranging from 2.14 to 2.45 kg/tree. During December to March, calculation of chilling hours below 12.5 °C was 141 hours during 2012–13 and 161 hours during 2013–14. The other seven cultivars did not flower and fruit during these 2 years of growth at Lalamilo, perhaps due to a greater requirement for chilling hours. At Kula, after 3 years of growth (2015), nine cultivars of olives with the exception of Moraiolo flowered and fruited. Mean fresh weight fruit yield in 2015 ranged from 0.25 to 22.06 kg/tree for various cultivars grown in Kula, Maui. In 2013, the oil from three cultivars grown at Lalamilo was analyzed for free fatty acids (FFA), peroxide value (PV), ultraviolet absorption for conjugated double bonds, 1,2-diacylglycerol (DAG), and pyropheophytins (PPP). Oil quality was within the range of extra-virgin olive oil. There is a need to investigate further the effects of temperature and management on flowering and fruiting of olive cultivars grown in Hawaii at various elevations. In particular, ‘Arbequina’, ‘Arbosana’, and ‘Koroneiki’ appear to have a lower requirement for chilling hours than other cultivars tested.