Good to Know--Assessing new cherry varieties
Lynn Long reports on new selections in an Oregon State University cherry variety trial that he has maintained for nearly 20 years.
Left to right: Kiona is an excellent-tasting early variety but lacks firmness. Santina is large and firm, though flavor is only fair to good—but acceptable for an early variety. Rain cracking is a drawback.Timing of Benton harvest is around Bing, but fruit size is larger than Bing, and it is more tolerant to cracking than Bing. Early Robin is 10 to 12 days ahead of Rainier, but unlike Rainier, possesses moderate rain cracking resistance.
As with much of the Pacific Northwest, the 2011 Oregon cherry harvest was far from ideal. A significant rain event late in the season destroyed much of the Skeena harvest. Yet, when I spoke with growers after harvest, most were optimistic about their potential for profit. One thing made this outcome possible, variety diversity. Fifteen years ago, a rain just prior to Bing harvest would have destroyed not only the Northwest cherry crop but also any hope of a profit. Growers have learned that with diversity comes protection. Some varieties escape rain damage by ripening before or after the rain event, while other varieties, such as Regina, have natural resistance to cracking.
For this reason, as well as reduced labor needs and the potential for higher profits due to an expanded harvest period, growers are always looking for good, new varieties. Of course it is important that any new variety is selected carefully, with as much supporting data as possible to avoid costly mistakes. With this purpose in mind, I have maintained a cherry variety trial in The Dalles since the mid-1990s including many new varieties and selections from around the world. I currently evaluate nearly 80 selections each year for bloom and harvest timing, fruit size and firmness, as well as pedicel-fruit retention force (stem pull force) and other quality attributes.
New additions include varieties in the “Star” series from the University of Bologna, Italy breeding program and the “Pearl” series from Cornell University. I hope to have data to report on these varieties soon. This article, however, will focus on several varieties that have been of interest, for one reason or another, to Northwest growers in the last few years.
Santina is a variety released by Pacific Agri-Food Research Centre in Summerland, British Columbia, Canada, in the 1990s. Obviously, it is not a new variety but there is renewed interest in this cherry as an early-season variety that can be harvested seven to ten days before Bing. It has been grown for some time in early production areas of Chile and Australia, but until recently, Northwest growers have overlooked it. The tree is self-fertile but moderately productive. The tree will do well on either Mazzard or a productive rootstock such as Gisela 6.
The fruit is very large and firm, with an excellent stem pull force. The flavor is only fair to good but acceptable for an early-season variety. Unfortunately, the fruit cracks in the rain. Rain crack percentages in the past have ranged from 20 percent in 2010 to up to 90 percent in 2005. In comparison, 55 percent of the Bing fruit split in 2005.
Kiona is an excellent tasting early variety, released from the Washington State University breeding program a few years ago.
Ripening time is similar to Tieton. It is self-fertile but has only moderate productivity, so it performs well on the more precocious rootstocks. Fruit size is large, commonly 9.5 row, with excellent stem pull force. For all of these reasons there was hope that Kiona would meet the need for a cherry ripening between Chelan and Bing. Firmness, however, is low with an average reading on our Firmtech 2 instrument of 244 grams per millimeter. Minimum acceptable firmness for fresh harvest cherries is 250 g/mm. Initially, I was hopeful that we would be able to overcome this deficiency by harvesting the fruit early as Kiona fruit is sweet even as it begins to color. At this early stage of development, I was able to obtain firmness readings above the acceptable minimum, but the fruit color was too light for good marketing potential.
Benton is another release from the WSU breeding program. It ripens with Bing or a few days earlier. Because it sizes late, it is difficult to harvest much earlier than at Bing harvest timing. That said, however, it offers a couple of advantages over Bing. Fruit size is larger, averaging 9.5 row, and there is a moderate level of rain crack resistance with this variety. In addition, flavor, firmness, and stem pull force are excellent.
Although it is self-fertile, it is not productive. This variety is one that does well on the more highly productive rootstocks such as Gisela 6 or 12. For the same reason, Mazzard should be avoided.
Cowiche ripens several days prior to Lapins. It was released by WSU along with Kiona in the mid-2000s. Perhaps its greatest attribute is its flavor. The flavor of Cowiche can best be described as intense. The fruit is very high in both acid and sugar, making for a very strong flavor. Possibly because of its flavor, birds seem to prefer this variety to others. Bloom time is moderately
late, and due to a unique allele combination, almost any late-blooming cherry can serve as a pollinizer. Fruit size is very large; fruit is firm and with good stem pull force. Unfortunately, there have been reports of pitting problems in storage with this variety.
With very large fruit size, excellent flavor, and moderate productivity on a self-fertile tree, who could blame growers for planting large acreages of this variety in the late 2000s? Hoping for a winner, they soon discovered, however, that the stem retention force was so poor that stems fell off the fruit during both harvest and packaging. In addition, a large percentage of the embryos fail to develop, so pits readily shatter in one’s mouth as the fruit is being eaten, potentially creating a hazard for both children and adults. In Oregon, most of these trees have been grafted over to other varieties as growers have moved on.
Oregon growers have been planting Regina for nearly ten years. Although the fruit is large and firm, it is grown mostly for its lower rain cracking potential, high packout rates, and the ability to arrive at distant markets in excellent condition. Ripening with Skeena, it is much more resistant to rain cracking. In 2011, 65 percent of the Skeena cracked, whereas only 20 percent of the Regina cracked in the trial block.
Regina is self-infertile and blooms very late, so finding good pollinizers for it can be a challenge. Sam and Stark’s Gold seem to work best, but both have limited potential for marketing. Attika, Schneiders, and even Skeena can work, but tend to bloom slightly ahead of Regina. Most Oregon growers plant a solid block of Regina and insert the pollinizer tree between the Regina trees every fifth tree in every row. Pollinizers are pruned hard each year to maintain their space. Due to lower productivity, Gisela 6, 12, or Krymsk 6 work well as a rootstock.
Growers looking to spread out their harvest of blush cherries now have an option. Early Robin was discovered in a Washington orchard a number of years ago and provides a good early harvest alternative to Rainier. Harvest time is 10 to 12 days ahead of Rainier. The flavor is similar to Rainier in that it gives an overall sweet impression lacking the strong acid balance of Bing. Fruit size is moderately large with excellent firmness and, unlike Rainier, possesses moderate rain crack resistance.
The tree is self-infertile, and Bing is commonly used as a pollinizer. The trees are only moderately productive, so they do well on some of the more productive rootstocks.