Unexpected chilling and Freezing stress is one of the most important problems for pomegranate growers in Iran. For example most pomegranate gardens were completely destroyed in the region because of severe winter freezing in 2008. Therefore a factorial experiment based on completely randomized design (CRD) was performed during 2008. Six genotypes included (Shirin e Poost Ghermez, Poost Sefid, Shahvar, Torsh e Malas, Shalghami and Shishe cap) and 9 temperatures in the range of -10 to -24 C were compared. The results showed that the amount of browning, proline content, electrolyte leakage and antioxidant activity were increased by freezing incubation, whereas survival percentage was decreased. Not any re-growth was recorded in 3 genotypes (Shirin e Poost Ghermez, Poost Sefid, Shahvar) in -18 °C but Torsh e Malas, Shalghami and Shishe cap genotypes showed 30, 21.5 and 61.2 survival percentages respectively. The cultivar ‘Shishe cap’ could stabilize its membrane structure and electrolyte leakage to -20 °C. The proline content of ‘Shishe cap’ showed 12-fold increase at -24 °C in comparison with control. Therefore it seems that ‘Shishe cap’cultivar was able to retain its osmotic potential effectively compare with the other cultivars.

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