Investigation of Frost Tolerance of Flower in Two Iranian Cornelian Cherry Clones

In many areas, low temperature is an important environmental limiting factor in production and distribution of horticultural trees and plants. This study was conducted to study the frost tolerance of main local clones of cornelian cherry in Tarom Sofla region, Qazvin, Iran. Cold treatments at 5 levels (+4, +2, 0, -2 and -4 ˚C) at two cooling periods (3 and 5 hours) were arranged as a factorial experiment, based on completely randomized design with 4 replications, at flowering stage of Golabie Siah (black pear) and Paeizi (autumn) clones in 2009-2010. For each treatment, the electrical conductivity (EC) and acidity (pH) were measured just after shaking (t=0), every 3 hours in the first 24 hours, and once daily in the 2nd to 8th day. After a week, the samples were autoclaved at 105˚C for 4 minutes and the changes were recorded. Results showed that the range of EC in flower was 92.2-846.2 µS/cm, and the range of pH varied from 6.4 to 7.7. Based on the results, the effect of frost intensity on EC changes was ascending, and on pH was slowly ascending and sometimes fixed. The highest value of EC due to destruction of tissues, as an index of frost damage of the flower, was obtained at +4 ˚C. Therefore, tolerance range of cornelian cherry flower has been estimated to be more than +4 ˚C.