Cultivar Trial of Olives (Olea europa) in Hawaii

Hawaii has the advantage of diverse ecological zones with 11 of the world’s 13 climate zones.  Many crop species can be grown in Hawaii, including olives (Olea europa) that are adapted to Mediterranean growing conditions with mild, rainy winters and long, warm, dry summers.  Ten olive cultivars were selected for oil production; six cultivars were transplanted on 24 February 2011, and four cultivars were transplanted at 13 July 2011, at the Lalamilo Research Station in Kamuela, HI, (760 m elevation; latitude and longitude, 20.0188°N, 155.6765°W).  The soil series was the Waimea series (medial, amorphic, isothermic, humic Haplustands).  Trees were planted in a randomized complete-block design with 1-tree plots replicated seven times at a spacing of 3 m in single row windbreaks.  Maximum/minimum air temperatures were recorded at the Lalamilo station, and the lowest minimum temperature recorded was 8.3 °C, which is above that reported to be required for breaking the dormancy of buds.  Yet, during April 2013, trees of three varieties (Arbequina, Arbosana, and Koroneiki) were observed to flower.  On 16 October 2013, five trees each of 'Arbequina' and 'Arbosana' were harvested, and six trees of 'Koroneiki' were harvested in a one-time harvest.  Average yields per tree were 1.89, 4.89, and 2.04 kg (fresh weight) and total yields were 8.8, 14.2, and 11.0 kg fresh weight, respectively for 'Arbequina', 'Arbosana', and 'Koroneiki'.  The average color of fruit was 3.5, 2.1, and 3.3, respectively.  Oil was milled from these fruit (in two presses), resulting in 2.0, 3.0, and 2.6 kg of oil (assuming a specific gravity of 0.91) or a yield of 22, 21, and 24%, respectively.  Oil was sent to the University of California, Davis, Analytical Lab and extra virgin olive oil quality was determined.  Apparently, the agro-environment of Kamuela, HI, is suitable for the flowering and fruit set of these three olive varieties.  Further research is needed to determine whether olive oil production is economically profitable in Hawaii.