Relationship between cold hardiness and dehydrin gene expression in peach shoot tissues under field conditions

The relationship between cold hardiness and expression of dehydrin genes in the shoots of four peach cultivars (Prunus persica ‘Daewol’, ‘Aikawanakajima’, ‘Fukuyokabijin’, and ‘Kiraranokiwami’) was quantitatively evaluated during seasonal cold acclimation and deacclimation. Cold hardiness was determined by electrolyte leakage analysis, which increased gradually during fall, reached a maximum level in midwinter, and decreased again in spring. According to the temperatures at which 50% injury occurred (LT50), differences in cold hardiness of ‘Daewol’ and ‘Kiraranokiwami’ were the most obvious during deacclimation, with the exception of April 2012. The expression patterns of PpDhn1 and PpDhn3 showed parallel fluctuations in cold hardiness in the four cultivars, whereas PpDhn2 did not show any seasonal changes in any of the cultivars.