Apple improves with age
WA 2 photographed two weeks before harvest.
Washington State University’s first new apple release, WA 2, is unlikely to get rave reviews when sampled straight from the tree, even though it’s sweet and crisp. That’s because the eating quality improves during storage and the apple is at its best during the spring and summer—when the quality of most other apple varieties is declining.
“WA 2 doesn’t eat well off the tree,” Tom Auvil, research horticulturist with the Washington Tree Fruit Research Commission, told visitors at a new variety field day at a test plot in Quincy in early October. “But the shelf life is just so incredible.”
In fact, storage tests with WA 2 have shown little benefit of applying MCP (1-methylcyclopropene), said WSU apple breeder Dr. Kate Evans. “It didn’t seem to make much difference. It holds up its texture really well without it.”
Nurseries in Washington State have virus-tested budwood of WA 2 and are set to propagate trees when approved growers request them. Excess test trees were sold to growers for commercial plantings last spring and some growers are propagating their own trees from certified wood for planting in 2013. Growers must sign an agreement with the variety owner, the WSU Research Foundation, before being allowed to grow the variety commercially.
So, is it a problem that WA 2 needs to be stored for a time before going to market?
Mike Hambelton, vice president of marketing at Columbia Marketing International in Wenatchee, Washington, thinks not. “We have plenty of varieties to sell in the fall—Gala, Ambrosia, Goldens, SweeTango….”
WSU’s second apple variety, WA 5, which is a tart red apple, is available to growers for wide-scale testing. It’s been tested for several years and last year, for the first time, some apples developed internal browning when stored in controlled atmosphere for longer than four months.
Dr. Ines Hanrahan, who conducted the postharvest tests, said last year was the first time that WA 5 had been stored in CA and it had never been stored so long before. The browning appeared in fruit from test sites in Prosser, Brewster, and Quincy, and seemed unrelated to whether the fruit was treated with MCP or not. Two types of browning were seen. One was mainly around the core, while the other was a more radial coloration that could be related to the storage atmosphere, but more likely the growing season. Then again, since it’s a new variety, it could have a totally different origin, she said.
This season, Hanrahan will repeat her experiments to see if the browning recurs, with the hope of pinpointing the cause. In addition, she’ll do tests to try to prevent browning from developing, such as holding the fruit for a week at around 50°F before putting it into CA and then storing it at 36°F instead of the usual 34°F. She’ll also try to keep the carbon dioxide level below 1 percent.
Hanrahan will also continue postharvest tests with WA 2. With the volumes available this year she will be able to run tests on complete bins, rather than small quantities of fruit, to gain more confidence about how it handles on packing and presize lines.
Because of how well WA 2 stores, she’ll try holding the fruit in long-term regular-atmosphere storage. Not needing to put the fruit in CA could potentially reduce energy costs and allow packers greater flexibility in opening storage rooms.
“We had fruit we stored last year for three months in CA and five months in RA, and it was still very good,” Hanrahan said.