Good Fruit Grower

September 2016

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14 SEPTEMBER 2016 Good Fruit Grower O ptimal performance of pears on trellises will continue to be elusive without a full dwarfing rootstock. Existing varieties can cut tree size by 30 percent, but to deliver the kind of light penetration necessary for successful production on a trellis, tree size needs to be reduced by an additional 20 percent. European growers and southern U.S. growers get all the dwarfing they need from quince rootstock. Unfortunately, quince lacks the cold-hardiness neces- sary to withstand Pacific Northwest winters, to say noth- ing of those of the Northeast. There are two rootstock prospects undergoing late- stage testing that continue to outperform the rootstocks colder-climate growers are forced to use. Developed in Germany, Amelanchier continues to do well in field trials in Oregon, and a quince rootstock research project is poised to enter a North American testing phase. Amelanchier Amelanchier trials in Oregon continue to show the rootstock's superiority to Old Home by Farmingdale 87, significantly outdistancing the industry standard's near-barren limbs with good fruit and flower production. A superior dwarfing rootstock, Amelanchier should shed more light on pears in trellises, especially in lower canopies, which is an ongoing problem with OHxF.87. (See "Let there be light" on Page 16.) It tests hardy to minus 40 degrees Fahrenheit, and, though there is still a ways to go, its precocity promises heavier production for the life of the tree. The plant is a genus of the Rosaceae family, consisting of about 25 species of deciduous shrubs and small trees, many of which are native to North America. Its bark is smooth, gray or, less commonly, brown. It has a five-pet- aled white flower and produces red to purple edible fruit. There are 32 Amelanchier ornamental cultivars and 25 Amelanchier cultivars grown for fruit. According to documents filed by the University of Saskatchewan Plant Science Department with the International Cultivar Registration Authority, the word "Amelanchier" is derived from a French word meaning "small apple." The plant has an uncommonly large list of common names with some interesting folklore attached to them. (See "By any other name" on opposite page.) Early returns Michael Neumüller, a horticulture researcher at the Bavarian Fruit Center in Hallbergmoos, Germany, has developed inter-specific and intra-specific Amelanchier hybrids. His goal was to produce a cold-hardy rootstock for pears, which he succeeded in doing. "He produced an extraordinarily cold-hardy plant, hardy to minus 40 degrees Celsius in midwinter, which showed relatively little damage at that temperature," said Todd Einhorn, a Michigan State University horticulture associate professor. (Minus 40 degrees Celsius happens to be equal to minus 40 degrees Fahrenheit.) In trials Einhorn conducted at Oregon State University prior to his moving to MSU in August, the rootstock was The big push for a dwarfing rootstock Pears Amelanchier rootstock continues to exceed expectations, while cold-hardy quince candidates have been narrowed to 14 accessions. by Dave Weinstock Todd Einhorn "Grafted with Anjou scions, (Amelanchier) yielded 20 to 30 bins per acre in its third and fourth leaf, while OHxF.87 had few flowers and no fruit." —Todd Einhorn

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