Effects of Temperature on Dehardening and Rehardening of Winter Cereals

Cold-hardened crowns of winter wheat (Triticum aestivum L.) and a winter rye (Secale cereale L.) readily dehardened upon exposure to warm temperatures. Crowns dehardened at a faster rate at 20 C than at 10 and 15 C. Dehardened plants were capable of rehardening in a short period of time upon exposure to cold-acclimating conditions. In all the dehardening studies, there was a high positive correlation between cold survival and water content of the crowns. Plants collected in the fall and stored at −2.5 C maintained the same level of hardiness for 17 wk.