Few fruits are branded as strongly with Southern California’s fresh, laid-back image as the avocado.
Mary Lu Arpaia wants to make the avocado better. The UC Cooperative Extension subtropical horticulturist gives a checklist of traits that the ideal variety should possess. “The tree should be semi-dwarfing, adaptable to high density plantings, early-bearing and less prone to alternate bearing,” she says. “Ideally, it will be stress tolerant and have some salt tolerance and of course, be of excellent flavor and possess good shipping and ripening characteristics.” Arpaia leads the avocado variety breeding program at UCR, which has existed since the 1950s. The goal of the research is to develop new and improved avocado varieties that meet the needs of California avocado growers. 16 | UCR Winter 2015
In the early 1980s, the program released a variety called the Gwen. It was similar to the known-and-loved Hass in its flavor and thick, pebbly skin, though the trees required nearly a third of the space to grow and produced twice as much fruit. But the Gwen never took off commercially, in part because it didn’t turn black when it ripened like the Hass. After that, the program’s former breeder planted more than 60,000 variety seedlings on farms across Southern California. Avocados are a particular challenge since the selection rate for promising varieties is about one or two selections per 1,000 seeds planted, according to Arpaia. Four varieties were eventually released from this mass planting: Lamb Hass, SirPrize, Harvest and GEM. The GEM avocado has the same excellent characteristics as Hass, but the variety is
more consistent in its production and the trees are more compact, so growers have fewer harvesting and maintenance costs. Now they’re evaluating even more varieties and hoping to release them over the next few years. Avocado lovers: Arpaia arranges avocado tastings each month at Batchelor Hall.
Published on Feb 10, 2015
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