Cherries 



A major objective of cherry improvement programs of the USDA and the various States 

 has been high quality sweet cherries with hardier wood and blossom than those available in 

 the past. 



Although sour cherry trees can tolerate temperatures as low as -30° F. when fully 

 winter hardened, sweet cherry trees are likely to be damaged at -20° F. Flowers of both 

 sweet and sour varieties are quite susceptible to cold, making them vulnerable to frost. This 

 and other special climate requirements - have tended to limit large-scale commercial produc- 

 tion of sour cherries to districts along the Great Lakes and production of sweet cherries to 

 the Pacific and Intermountain States. Even in these areas, cherries are subject to cold dam- 

 age when winters are unusually severe. 



USDA efforts to provide hardier cherries for the Great Plains have relied primarily on 

 breeding new varieties through the hybridization of winter-hardy sour cherries with sweet 

 cherries. At the same time, a sizable collection of wild and cultivated varieties and mutations 

 of both sweet and sour cherries has been gathered in this country and abroad and is continu- 

 ally being increased by new selections. This facilitates testing and evaluating a wide range 

 of cherries to locate hardy kinds suitable for use as germ plasm, rootstocks, or commercial 

 varieties. 



Several promising new varieties have been named and introduced as a result of this 

 systematic research. 



Rainier is a hybrid of Bing and Van which combines the superior bud hardiness of 

 Van with the large size and firmness of a Napoleon type cherry. Developed in a Federal- 

 State project at the Washington Irrigation Experiment Station, Rainier was introduced in 

 1960. 



Another new hybrid developed at the Washington Agricultural Experiment Station at 

 Prosser is Chinook, a cross between Bing and Gil Peck. Although it is not particularly 

 cold hardy, Chinook ripens 4 to 10 d.ays earlier than Bing without being any more susceptible 

 to cold. Although neither the Rainier nor Chinook has all the desirable traits such as rain- 

 cracking resistance sought by plant breeders, they were selected and introduced for commer- 

 cial trial. At the same time these hybrids and other sweet-cherry crosses are being used as 

 a basis for developing and selecting still better varieties in the future. 



Also at Prosser, 20 sweet cherry selections have been made from among 750 progeny of 

 the Rainier and Chinook varieties and sister seedlings. One selection is particularly outstand- 

 ing for its hardiness and vigor. 



In breeding experiments at the Northern Great Plains Field Station, Mandan, N. Dak., 

 the sandcherry has been crossed with hardy plums. These experiments have produced two 

 sandcherry-plum hybrids that are sufficiently hardy for planting in milder sections of the 

 Northern Great Plains, especially in sheltered sites. These sandcherry-plum hybrids, Saca- 

 gawaea and Hiawatha, are bush-type plants that bear high quality fruits. 



At the USDA Horticultural Field Station in Cheyenne, Wyo., several hybrids made 

 by crossing sweet and sour cherries are currently being evaluated for adaptability to the 

 Northern Great Plains areas too cold for sweet and sour cherry varieties presently available. 



The tree-fruit testing program at Cheyenne is a long term one, having been under way 

 for more than 28 years. From evidence of these tests and fruit growing experiments in other 



" In addition to being vulnerable to spring frosts because of their tender flowers, cherry trees are ad- 

 versely affected by hot, dry summers and are susceptible to brown rot in the more humid areas. 



