Low temperature injury in peach and nectarine cultivars

Winter hardy and late blooming peach and nectarine varieties can be grown successfully in Hungary. In some years even the most hardy varieties can be damaged by low temperatures. Thirty fresh market type-peach, 4 processing clingstone peach and 26 nectarine varieties were tested in Szatymaz, Southern Hungary, in an important peach growing area. In 1995, 2 to 5 days prior to blooming -7 degrees C caused 8% (Cresthaven) to 97% (Regina) damage to ballon stage flowers. In the winter of 1996/97 the temperature dropped to -20 degrees C, causing 9% (Lacika fele) to 89 % (Armking) of flower buds to be damaged. In April 1997, in the first days of blooming 7% (Cresthaven) to 97% (Domiziana) of the flowers were damaged by -5 degrees C. There was a correlation between the rate of damage and the start of flowering. In case of early blooming cultivars the rate of damage was higher not only in the flowering period but in winter as well, compared to late blooming cultivars. The yield was determined not only by frost damage, but by density of flower buds and by fruit set. The density of flower buds varied between 0,22 pcs/cm (Maria Luisa) and 1,10 pcs/cm (Armking). Fruit set of open pollinated flowers ranged from 22% (Cresthaven) to 84% (Primerose). Based on the characteristics studied the best varieties were selected for growing.