Department of Horticulture, Seed and Plant Improvement Institute (SPII), P.O. Box31585-4119 Karaj, Iran.
Department of Horticulture Science, Faculty of Agriculture, Abhar Branch, Islamic Azad University, Abhar, Iran
Almond is one of the most important nut crops in Iran. Due to the suitable climatic conditions, Iran is one of the most important growing centers for wild and domesticated species of almond in world. Native genotypes typically are early flowering, due to late spring frost, often; they have been damaged. So frost damage to the flowers and early developing fruits is one of the most limiting factors in the most almond cultivation regions of the world. This study was undertaken to help understand almond response to frost damage at different phenological stages, in order to develop criteria for the selection of cultivars with improved resistance to frost on the basis of field experiment with temperature fall (-4˚C in 21 march 2010) was occurred naturally. In this stage, all early, medium and late flowering almonds damaged, but damage severity was different. Obviously, there was genetic diversity for cold resistant among genotypes and varieties of almond. Frost damage percentage of cultivars and genotypes after frost was measured at least 100 flowers of each cultivar with 3 replications. Results showed that the severity of frost damage was influenced by genotypes of almond and stage of flower bud development and other indices such as leafing stage. After the evaluating the 29 almond selections, based on flowering time and late frost spring resistance, they were divided into high cold resistant; medium cold resistant; low cold resistant and very low cold resistance. Also, it was found that one promising genotypes with high late frost spring resistant was medium flowering.