Effects of cold stress on some Apricot (Prunus armeniaca L.) cultivars in different phenological stages

One of the main problems in fruit production is the ambient low temperatures. It means that low temperature in early spring compromised the flowers and fruits. Apricot tree is known as an early blooming and sensitive to frost. In accordance to this in East Azarbaijan which is one of the important apricot production regions in Iran, rate of frost resistance of a few commercial apricot cultivars as Nassiri, Ghermez Shahrood, Dorosht Malaier, Ghorban Maraghe and Kanino were investigated. Experimental samples were studied under four different cold treatment levels (+2, 0, -2, -40C). Experimental traits include sensitivity and difference of anther, petal, stigma, style and ovary to temperature treatment, which have been morphologically evaluated. About all cultivars with progress of phenological stages and temperature decrease, damage percent increased. Among the above cultivars, Dorosh Malaier had a lowest and Ghorban Maraghe had a highest damage percent in low temperature. Nassiri, Ghermez Shahrood and Kanino were palced among mentioned cultivars. Proline quantity after cold treatment was evaluated as well. The results showed that between increase in proline and cold resistance in above mentioned cultivars don’t have a complete liner correlation.