The Effect of Changing Temperatures on Hardiness, Respiration, and Intensity of Rest of Dormant Peach and Apricot Buds

studies were conducted to better understand the influence of temperature on the rest period of dormant peach and apricot buds. Gleason Elberta peach and Chinese apricot trees in the field at Howell Experiment Station in Ogden were used to evaluate rest intensity, respiration, and cold hardiness in relation to temperature. A rest intensity curve was obtained for both species using various concentrations of gibberellic acid. It was found that temperature had no direct effect on the depth of rest and that the depth of rest had no measurable influence on respiration and cold hardiness. Respiration of flower and leaf buds was not affected by temperature until after the rest period was over and the temperature rose above 40 F. However, cold hardiness was directly affected by temperature during the rest period. As the temperatures dropped the cold hardiness increased in both species. Lovell peach seedlings were placed in 5 gallon containers and placed in controlled temperature chambers. At 3 different periods, 3 trees were removed from 9 different temperature treatments. It was found that 40 F was generally more effective in breaking rest than was 32 F. Light did not seem to affect the rest period significantly