ground and is protected by snow or naturally occurring or applied mulch. Another nonhardy 

 small fruit plant, which frequently survives freezing weather because of its growth habits, is 

 the cranberry. Commercially, the cranberry is grown in bogs which can be flooded at the 

 approach of extremely cold weather. 



A brief report on problems, progress, and prospects in developing improved varieties of 

 some of the more common kinds of small fruits follows. Most of the small fruits discussed 

 in this section — including red and black raspberries, blackberries, blueberries, and grapes — 

 are deciduous. Although they are evergreen and not truly hardy, strawberries and cranberries 

 are also discussed briefly because they too are grown in northern areas where cold damage is a 

 problem. 



Raspberries 



Although both red and black raspberries are somewhat more cold hardy than blackberries, 

 they are subject to winter damage in some areas of the United States. The canes may be 

 killed by sudden freezes and the blossoms hurt by late spring frosts. Consequently, cold 

 hardiness is among the important objectives of raspberry improvement programs along with 

 disease resistance. 



As a group, red raspberries are more tolerant of cold than are black raspberries. For 

 example, some varieties of red raspberries will survive in the upper Mississippi Valley where 

 black raspberries are frequently winterkilled. 



In 1951, the red raspberry variety Canby was introduced after testing in a cooperative 

 breeding project of USDA and the Oregon Agricultural Experiment Station at Corvallis. A 

 seedling of the cross of Viking and Lloyd George, the Canby produces large red raspberries of 

 good color and flavor. The Canby is hardy under Western conditions but not in the East. 

 Raspberry work is continuing at Corvallis. 



At Carbondale, 111., USDA and Southern Illinois University scientists are hybridizing 

 Asiatic and American species of black and red raspberries to develop disease-resistant and 

 winter-hardy varieties. Some full-fruiting seedlings of these crosses show commerical promise. 



Blackberries 



In blackberry improvement projects of ARS and various Northern States, a major objec- 

 tive is to reduce crop losses through the development of new varieties that are more cold 

 hardy. Their susceptibility has precluded the successful production of blackberries in some 

 areas with severe winters and made them vulnerable to sudden freezes in milder sections of 

 the country. For commercial growers in established blackberry-growing areas, there is par- 

 ticular need for varieties that combine hardiness with disease resistance and thornlessness. 

 The sharp decline in the blackberry industry during recent years has been attributed to 

 inability to obtain labor to harvest the old productive, cold-hardy, thorny types of blackber- 

 ries. In colder areas, the emphasis is on hardier varieties. 



The search for hardier blackberries has taken USDA plant explorers to far places. In 

 1957, for example, two varieties of large and hardy blackberries were brought back from 

 the high Andes for evaluation and possible use in blackberry improvement programs. 



Although a number of improved varieties have been developed in recent years, the 

 need to combine cold hardiness with other desired characteristics complicates the problem. 

 For example, none of the thornless blackberry selections being tested at the Plant Industry Sta- 

 tion, Beltsville, Md., was fully winter hardy during the severe 1961 winter and none was as 

 hardy as Darrow and Eldorado varieties. And Williams, a 1962 introduction developed by 

 USDA in cooperation with the North Carolina and Mississippi Agricultural Experiment Sta- 

 tions, is resistant to many diseases prevalent in the South but is not sufficiently cold hardy 

 for growing north of Virginia and Tennessee. However, Aurora, which was introduced in 



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