WA 2 update

Washington State University’s first new apple variety, WA 2, is in its second season of intensive industry evaluation (Phase 3). As in 2010, horticultural and storage performance was evaluated in the 2011 season, while the remaining fruit was used for packing-line tests, industry sampling, and market testing. In addition, a full bin sample was graded with commercial equipment and analyzed for defects. Gift boxes with storage samples were distributed between January and March to nurseries, packers, and industry organizations.

Horticultural performance

The fourth- and fifth-leaf orchards of WA 2, planted 10 feet between rows and 3 feet between trees (1,452 trees per acre), provided the first commercial quality and ­volume of fruit in our Phase 3 trials in 2011.

In 2010, the yield in Quincy was the equivalent of 46 bins per acre, increasing to 79 bins per acre in 2011 ­(top photo). Fruit size in 2011 in Quincy peaked on 64 to 88.

WA 2 is a compact tree on a Malling 9-vigor rootstock. It is an easy and inexpensive tree to maintain. In replant sites or sites with weaker soils, the trees may not grow vigorously enough to fully develop a productive canopy. If Gala or Fuji on M.9 will grow to 11 feet tall in two seasons when spaced three feet apart, WA 2 will be more successful when spaced at two feet. Extra effort in water management, nitrogen application, and removal of crop from the central leader to maintain vigor until the canopy is filled, will significantly improve yields. WA 2 is easier to thin than Fuji, but tends to produce fruit on one-year wood that is often small, russeted in the stem bowl, and parrot-beaked. However, there was little parrot beaked, russeted, or undersized fruit in 2011.

In 2011, best harvest dates for WA 2 in the warmer regions were after October 10; in the cooler regions, optimum harvest timing was after October 20.  Two picks may suffice for WA 2 as the trees become more mature. However, stem-bowl splitting is a factor to consider, as cold weather during maturation or advanced maturity (deep red color) may aggravate splitting. Two sites had four picks in 2011, with the early light picks focused on the southwest side of the trees. WA 2 may have a two-week harvest window for long-term storage, with very good fruit color.

Storability

The following storage conditions were utilized on WA 2 in the 2011/2012 storage season: 4 months in regular atmosphere, 6 and 10 months in controlled atmosphere, or 10 months in CA with MCP (1-methylcyclopropene). All fruit was drenched with a postharvest fungicide prior to storage. WA 2 produces low amounts of ethylene. The fruit needs 3 to 4 months of regular storage to convert its starch to sugar, followed by several days at room temperature to develop optimum flavor. WA 2 fruit maintains its quality in storage; fruit from CA storage in March was very similar in quality to fruit off the tree at harvest and still required a period at room temperature to develop ­optimum flavor.

Appearance is another trait that improves in storage with the color brightening considerably. The faint hues of over-color, which are slightly beige at harvest become a light, bright pink by the end of January. Color margins were more distinct after storage. Storage ­experiments are ongoing and will be reported on this fall.

Commercial packout

Apples from the second pick at Quincy were graded based on percentage of red color and the amount and severity of defects. Fruit with 60% or more red was classified as first grade, and below 60% was second grade. Fifty-seven percent of the fruit was first grade. In a defect analysis performed prior to presizing, 86% of fruit was free of defects. Stem punctures (4%), limb rub (4%), insect damage (2%), and parrot beak (1%) were the most prevalent defects. Some decayed fruit (1%) was present, mainly due to stem punctures at harvest. Only 0.3% of fruit was affected by a stem-bowl split, and there was no sunburn or bitter pit.

Flavor

This year’s evaluation demonstrated the need for WA 2 to warm up to gain flavor and how the variety retains firmness and crispness while held at room temperature, which is a unique trait. CA storage has a similar impact on WA 2 as MCP has on many other cultivars in terms of low volatile (flavor) production, slow conversion of starch to sugar, and no loss of acidity, thus MCP appears to be unnecessary for WA 2 long-term storage.

Gift boxes

At several time points during the storage season, gift boxes were distributed to producers, packers, and general public for evaluation. The following is a summary of the first batch, which was largely distributed in the Yakima area in late January. The fruit came from the second pick in Quincy and was held for three months in regular atmosphere storage prior to waxing. Fruit was run over a commercial packing line and waxed at Valley Fruit in Wapato in mid-December and packed into one-layer gift boxes, which were held in cold storage until distribution. The total number of 122 respondents/ tasters was estimated through feedback interviews by Washington Tree Fruit Research Commission staff. The group was diverse in age, ethnicity, educational ­background, and apple eating habits.

Response to the apple was as follows:

Liked    88%
Disliked    3%
Not sure    3%
Good, not great    7%

We received no negative responses regarding appearance and texture, though some respondents noted the fruit was bland. We also noted that women liked the apple a lot, and that negative comments were closely correlated with male respondents associated with the fruit industry.

In summary, the fruit performed extremely well in the extended storage and the packing-line trials, while exhibiting outstanding appearance and eating quality.

Ines Hanrahan and Tom Auvil, ­Washington Tree Fruit Research ­Commission; and Kate Evans, ­Washington State UniversityThe authors would like to thank AgroFresh, Valley Fruit, and the Washington Tree Fruit Research Commission staff.