Children enjoy novel hybrid fruits during a tasting at California Polytechnic State University in San Luis Obispo.
Zaiger Genetics, Inc., internationally acclaimed for developing interspecific fruit, is breeding cherries and plums together in the search for a hybrid cherry-plum, or cherum.
The Modesto, California, fruit-breeding company has had success in creating novel fruit from plum and apricot crosses (pluots and apriums). Moreover, they are working to develop commercial selections of the peacotum, a three-way cross of peach, apricot, and plum hybrids. But their latest venture of breeding cherries and plums has exciting potential for commercial growers, according to Dennis Tarry of Dave Wilson Nursery in Hickman, California. Dave Wilson is the exclusive U.S. licensor and primary propagator of varieties developed by Zaiger Genetics.
Tarry said that although Zaiger has not come up with a trademarked name for interspecific cherries, they are working with about 50 hybrid crosses of cherries and plums. In 2009 and 2010, they expect to have more cherrylike progeny from last year’s crossing of the cherry interspecifics (cherry and plum crosses) back to cherries.
The intent of crossing cherries with plums is not so much to develop a new fruit, as it is to make the cherry more grower friendly, he explained. “The goal is that the new fruit would be less prone to cracking even with high sugars, be naturally firm without the need for growth regulators like gibberellic acid, and have later maturity dates stretching into August and September, a benefit from the plum genetic material.
“If it could have all those traits and still be a cherry, that would be something,” Tarry said. “They’re trying to put genetics into cherries that don’t really exist.”
But, he stressed, size and quality are important—the fruit needs to be high quality and cherrysized, not the size of a small plum. While there may be a niche market for super sweet, 30-plus-Brix, small fruit, the goal is to end up with more cherrylike material.
Exotic fruit crosses create attention, but Zaiger’s mainstay business is developing improved stone fruit varieties for commercial growers. Dave Wilson Nursery recently released the following Zaiger cherry varieties:
Royal Hazel and Royal Lynn are low-chill, early varieties developed for warm winter climates as in California’s southern San Joaquin Valley where it can be difficult in some years to reach enough chilling hours for uniform bloom. Both selections are productive and produce sweet, high quality, large fruit; 10 row for Royal Hazel, 9 to 9.5 row for Royal Lynn. They are more resistant to cracking than Bing but not as good as Chelan grown under California conditions.
Rosie Rainier is a high-colored Rainier harvested 12 days before Bing. The large fruit show about 70 percent red color over a yellow background. With the higher color, blemishes are not as apparent. In Tarry’s own orchard, after windy weather last summer, Rosie Rainier fruit fared better than Rainier cherries in not showing skin blemishes from wind damage.
Royal Edie and Royal Helen are what he calls the “Royal Darlings.” The two varieties are sisters and can be planted together as pollinizers and packed in the same box together. Both selections bloom a few days after Bing and mature three to four days later than Bing. He believes they fit a good time slot because in California, there are only a few varieties, such as Benton, Sandra Rose, and Regina, blooming at that time. Fruit are large, with about 90 percent of the packout sized at 9.5 row. They are a high-Brix cherry and have better cracking resistance than Bing. He noted that both varieties have been planted in the Pacific Northwest, but none of the trees in Northwest trials are producing yet.
Tarry has both varieties planted together in one block in his personal orchard. “The Darlings are the most perfect cherry, in my opinion, I’ve ever seen,” he said, adding that his first crop was marketed to a high-end grocery chain. “I got a phone call from the retailer shortly after delivery and was worried about what they were about to say. But they called because they wanted to contract for the same cherries the next year.”
Dave Wilson Nursery is evaluating a few early season cherry selections, one for which they see potential for a limited acreage, managed variety. The high quality cherry matures 22 days ahead of Bing and has appeal for the early market. Another low-chill selection that matures 14 days ahead of Bing could help lengthen the early season market for cherries. He believes that both are more suited for California growing conditions because there would be a concern for spring frost damage in colder regions.
Not long ago, the stone fruit breeding program at Zaiger Genetics emphasized subacid peaches and nectarines. Nowadays, Tarry said things are shifting to developing fruit with more balance between sugars and acidity.
Emphasis at Zaiger has been to develop nectarine selections for the early season, a marketing slot that has lacked good-tasting varieties, he said. “We think we’ve found a winner with Polar Light, a white-fleshed, high-colored nectarine that matures around May 15.” Another early, yellow-fleshed nectarine recently released is Honey May.
New Pluot varieties developed by Zaiger continue to be released, especially ones that mature in the July gap, like Ruby Cat, a high-flavor, self-fertile Pluot. A new late-season Pluot, Flavor Fall, matures at the end of September to the first week of October.
For growers who have had difficulty finding suitable pollinizers for Pluots, he recommends using both the Pluot Amigo 1 and Amigo 2 varieties. Amigo 1 blooms earlier than Amigo 2, providing an overlap of blooms.
Several unique peach, apricot, and plum crosses are commercially available at Dave Wilson Nursery, along with red and black Pluots, apricots, and Apriums. The Black Kat is a very dark Pluot. Spice Zee is a white-fleshed nectarine with a cinnamon and spice flavor. The tree, with red leaves, has ornamental appeal for the home gardener.