PRI Disease Resistant Apple Breeding Program

Co-op 1
Co-op 3
Sir Prize
Co-op 6
Co-op 7
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Co-op 9
Co-op 10
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Co-op 12
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Co-op 20
Williams' Pride
Co-op 24
Scarlett O'Hara
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Co-op 28
Pixie Crunch
Co-op 34
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Co-op 37
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Co-op 44


Co-op 13

(PRI 2175-7 = 'Raritan' x PRI 1018-101) Introduced as 'Redfree' (Williams et al. 1981) U.S. Plant Patent No. 4,322

Brief Description

  • Fruit: 64 to 76 mm (2-1/2 to 3 in.); slightly oblate to round, regular; light green to pale yellow ground color; washed and faintly striped, very bright finish; 70 to 95% medium red, medium grained, light yellow to cream colored, firm, crisp and breaking yet slightly tender flesh; mildly acid to sweet, slightly rich and pleasant flavor; juicy; very mild, good dessert quality. Moderate fruit size. Annual cropping. Retains quality for 1 month or more in refrigerated storage. Fruit hangs on the tree until well over-ripe.
  • Tree: Vigorous, spreading growth habit, 90 degree crotch angles, moderately spurry. Slightly leggy branches with a limited basal portion of the branches bare-wooded. Moderately large sized tree. In 1978, 'Redfree' showed minimal damage in a test winter at St. Jean-sur-Richelieu, Quebec, Canada, when the majority of the apple collection showed significant winter damage. Other reports from North Dakota, Minnesota. and Canada indicate that 'Redfree' is resistant to winter cold injury.
  • Season of Maturity: Seven weeks before 'Delicious'.
  • Disease Resistance: Field immune to apple scab; field immune to cedar-apple rust; moderate level of resistance to powdery mildew; good level of resistance to fire blight.
  • Problems: Powdery mildew may warrant control only under severe disease pressure; some feel that the flavor is too mild and bland; uneven ripening, requiring two or more pickings; slight tendency toward biennial bearing habit after heavy fruit set; some tendency to set heavy crops, resulting in reduced fruit size if not properly thinned; somewhat leggy growth habit with manageable amount of undesirable bare wood.
  • General Recommendation: Suggested for commercial use, as well as small scale and home grower plantings. Produces relatively high duality, low-acid fruit, with pronounced color and adequate storage-life for early entry into the summer apple market. Resistant to winter cold injury and expected to be well adapted in the North Central U.S., Southern Canada, and similar climates.

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