The effect of accumulation of chilling hours and the rate of linear heat on the behavior of some pistachio vera varieties

Winter chilling requirements are critical for flowering and fruiting of many fruit species, with evidence that pistachio has been adversely affected by warm winter, so that estimating chilling and heat requirements is crucial for identifying appropriate cultivars for given site. In our study, different levels of chilling hours were applied (500-600-700-800-900-1000-1100-1200-1300-1400 h).

Chilling Requirements of Pistachio. Determination of Chill Hours Required for Pistachio Variety Peters

The research trial was carried out at University of California, Davis, Agriculture and Natural Resources, Cooperative Extension–Kearney Agricultural Center (KAC). Part of the scientific work in the laboratory started from November 1, 2001 throughout the end of February 2002. This trial was conducted using Pistacia vera; the female variety ‘Kerman’ and its pollinator, variety ‘Peters’;… both are grafted on the rootstock UCB1.