Cold hardiness of peach flowers at different phenological stages

At the colder peach production regions it is important to know the cold hardiness of peach cultivars at different phenological stages of flowering. In our experiment, artificial freezing tests were conducted in a climate chamber in five selected years between the period of 2007 and 2016 to determine the freeze tolerance of generative organs of three peach cultivars ('Venus', 'Redhaven', 'Piroska') at different phenological stages of bloom. Based on the results of the laboratory freezing tests LT50 values were calculated. Our results showed that LT50 values of examined peach cultivars in swelled bud stage averaged over five years were between -6.8 and -11.2°C according to cultivar, and as phenological phases progressed, cold hardiness of generative organs decreased. At the end of bloom LT50 values varied between -1.7 and -4.1°C. Cultivar 'Piroska' had the highest freeze tolerance and cultivar 'Venus' showed the lowest in each year studied. This study shows that trees with delayed development are more prone to cold damage to flowers.