Some of the hardiest native American grape varieties will endure as much cold as apples. 

 However, Old World (vinifera) varieties grown in California and other Western States are 

 not hardy enough to succeed in the Northeast, where native American varieties or varieties 

 developed from them alone or by hybridization with vinifera varieties are grown. A high 

 quality seedless grape hardy enough to grow in colder areas would be useful in the Northeast. 



Strawberries 



Strawberries are probably grown as far north as any fruit but few established commercial 

 varieties are genuinely cold hardy in the sense that vital plant parts will stand exposure to 

 extreme cold. 



Although plants of most strawberry varieties will tolerate temperatures as low as 0° F. 

 when fully hardened and a few varieties (such as Howard 17, Senator Dunlap, and Gem) 

 will tolerate extreme cold, unhardened strawberry plants of most commercial varieties may 

 be killed by temperatures of 20° F., if their crowns are exposed. Consequently most varie- 

 ties are able to survive the severe winters of the northern part of the United States only 

 when protected by snow, natural vegetative cover, or applied mulch. And even in milder 

 areas, early blooming and blossom-tender varieties are subject to damage from spring. frosts. 



In the search for hardier strawberries, plant researchers have collected and studied wild 

 strawberry plants growing in colder areas of the United States and in foreign countries. A 

 wide variation in cold hardiness was observed among varieties, selections, and selected clones 

 of species. An unusual degree of winter hardiness was found in some clones of Fragaria 

 ovalis, a wild Rocky Mountain strawberry, while unusual blossom hardiness was found in 

 selected clones of F. virginiana, found growing in North Dakota, and of the Rocky Mountain 

 strawberry. These selections along with other promising sources of hardiness are being used 

 in breeding experiments. Among these are South American selections of F. chiloensis, which 

 was brought back to this country by USDA plant explorers because of its large fruit size and 

 firmness and ability to survive the extreme cold and drought of the Andes. 



Strawberry breeding work has been going forward in this country for well over a cen- 

 tury. Early breeding work was done on a rather limited scale by a few private breeders but 

 since 1920 the tempo of research has been stepped up by participation of public agencies. 



Hovey, a new strawberry variety originated in 1 834, was the first variety of any kind 

 of fruit developed in this country through breeding. Since that time, many improved varie- 

 ties of strawberries have been originated. 



Breeding experiments using blossom-hardy clones of F. virginiana and Midland (an 

 early, blossom-tender variety) resulted in a high percentage of hardy seedlings. Earlidawn 

 and Howard 17 are two early varieties that possess blossom hardiness. 



Breeding experiments using hardy clones of Rocky Mountain strawberries (F. ovalis) 

 in crosses with cultivated varieties have resulted in a number of improved varieties which 

 combine extreme winter hardiness with large fruits, vigorous plants, high runner production, 

 and high fruit quality. Introductions resulting from this work include Early Cheyenne 1 , 

 Cheyenne 2, Cheyenne 3, Sioux, Arapahoe, Radiance, and Ogallala. The ability of these 

 crosses to stand extreme cold makes them a good source for further breeding. 



Despite advances that have been made through breeding, improved varieties that com- 

 bine tolerance to low temperatures and bud hardiness with other desired traits, such as disease 

 resistance, firmness of flesh, and toughness of epidermis of fruit, are needed. 



The task of developing winter-hardy strawberries to meet the needs of U.S. growers 

 and consumers is magnified by the fact that strawberries are very subject to their environ- 

 ment and a variety that is good in one locality is likely not to be good in another. Conse- 

 quently plant breeders are faced with the job of originating superior varieties for particular 



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