RELATIVE HARDINESS OF BLOSSOMS AND SMALL NUTS OF NINE ALMOND CULTIVARS

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  • 1 University of California Cooperative Extension, 2279 Del Oro Avenue Suite B, Oroville, CA 95965

Almond (Prunus dulcis Mill.) cultivars vary in tolerance to cold with flowers at pink bud more tolerant than at full bloom or than small nuts. Branch samples 60 cm long with 30-100 blossoms or nuts were cut, sprayed with water, and artifically frozen. Subsamples were removed after exposure to 4 to 6 successively lower temperatures for 30 minutes. After 48 hours of ambient temperatures, flowers or small nuts were sectioned and examined for visual evidence of injury. Of the early cultivars, `Peerless', is most sensitive at full bloom and `Sonora' is most hardy. `Sonora' is especially hardy at pink bud. `NePlus Ultra' is intermediate. Of the mid-blooming cultivars, `Carmel' is most sensitive to cold while `Nonpareil' is most tolerant. `Price' is intermediate. The late blooming cultivar, 'Mission' is most sensitive while 'Padre' and 'Butte' appear similar. This study compared several popular new cultivars to older industry standards.

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