Sidebar: Olive cultivars field-tested in super-high-density system in southern Italy

Abstract

Olive cultivars field-tested in super-high-density system in southern Italy California production of extra-virgin olive oil is reportedly about 2% of total U.S. consumption, with the rest im- ported mainly from Italy and Spain. In ccording to the International Ol- recent years, California has started in- ive Oil Council, world olive oil creasing its oil olive acreage. California consumption has risen from 2.8 mil- olive growers have planted more than lion tons (1991-1992) to 3.5 million tons 22,000 acres since 1999, about 12,000 (2005-2006), due to increases in the acres of which is in the super-high- consumption of healthier foods in many density olive system, with tree densities countries, including the United States. of 676 per acre or more. This system al- The market outlook for extra-virgin ol- lows for mechanical planting and har- ive oil is very good, and many countries vesting of olives, reducing labor costs. are actively increasing their olive acre- We believe that super-high-density ages, particularly in North Africa, the olive culture can help to assure profit- Middle East, South America, Australia ability for both European and U.S. olive and the United States (Godini 2010). growers in the coming decades. This The Mediterranean’s traditional olive model, born in Spain at the end of the industry is based on production sys- 20th century, has resulted in noticeable tems that are hundreds of years old and increases in yield per acre. Up until characterized by low yields and high now, super-high-density olive culture production costs. The European Union has utilized a limited number of culti- subsidy system, which has helped vars, primarily ‘Arbequina’, ‘Arbosana’ European olive farmers to stay in busi- and ‘Koroneiki’, which possess suitable features such as a semi- dwarf habit, early bearing (first production at the second-to-third year after planting), consistent ini- tial crops (more than 2.2 pounds per plant), crop stabilization between 5 and 6 years, and fruit that is impact-resistant and has good oil quality (Godini and Bellomo 2002). The results that we pres- ent here are preliminary. Considering that Italy’s Mediterranean climate Super-high-density hedgerow planting systems for olives is similar to California’s, employ over-the-row harvesters (shown, in California). we believe that soil and ness, will end in 2014. Moreover, the climate differences should have little application of a “free exchange” area influence on the applicability of these in 2010 will legalize the importation of findings to California. lower-cost extra-virgin olive oils from Experimental orchard the southern Mediterranean Basin into In summer 2006, we established Europe (Godini 2010). Year after year, a new experimental orchard at the profitability of Italy’s traditional Valenzano, near Bari, in the experimen- olive culture becomes increasingly tal farm of the Dipartimento di Scienze doubtful, notwithstanding the world- delle Produzioni Vegetali at University wide renown of so-called “Made in Italy” extra-virgin olive oil (Godini and Aldo Moro of Bari, Italy. In addition to standard clones of ‘Arbequina’, Bellomo 2002). by Angelo Godini, Gaetano Alessandro Vivaldi, and Salvatore Camposeo A Paul M. Vossen ‘Arbosana’ and ‘Koroneiki’, two ad- ditional cultivars were introduced: ‘Coratina’, the most popular Apulian olive oil cultivar, and ‘Urano’, a new Italian cultivar considered by our research group to be well-suited for super-high-density olive culture. The olive trees were propagated in commercial nurseries by softwood cut- ting, and the experimental orchard was established according to the super-high- density planting scheme (676 plant per acre, with a tree spacing of 157.5 inches by 59 inches) and a north-south row orientation. The trees were trained to central leaders. Drip irrigation was sup- plied to each tree every 3 days between late spring and late summer, increasing from 423 cubic yards per acre annually in 2006, to 476 in 2007, to 794 in 2008 and 2009. Harvesting was performed on Nov. 20 in 2008 and 2009, in the third and fourth years after planting, respec- tively, using the Pellenc Activ’ 4560 har- vesting machine. Cultivar performance Vegetation. In December 2009, the average tree height had reached 107 inches, 5.3 times the initial growth of the previous year, with a maximum of 7.6 times more growth for ‘Arbequina’ and a minimum of 2.2 times more for ‘Urano’ (table 1). Only the crown width of ‘Coratina’ exceeded 79 inches by TABLE 1. Tree height at planting (June-July 2006) and December 2009, crown width in December 2009 Crown width December 77.5b 77.7b 96.5a 78.4b 74.5b Tree height Cultivar Arbequina Arbosana Coratina Koroneiki Urano Mean Planting 14.1b* 13.0b 16.9b 16.0b 41.1a December inches 107.3b 97.0c 120.9a 117.6a 92.7c * Within the same column and for a single parameter, different letters mark values significantly different at P = 0.01 (SNK test). http://californiaagriculture.ucanr.org • JANUARY–MARCH 2011 39