As the seasons progress, autumn-planted winter wheat plants (Triticum aestivum L.) first gain then progressively lose freezing tolerance. Exposing the plants to freeze–thaw cycles of -3/3 °C results in increased ability to tolerate subsequent freezing to potentially damaging temperatures. This study was conducted to determine to what extent the length of time that a plant is grown at low temperatures influenced the effectiveness of this freeze–thaw enhancement of freezing tolerance. Plants from six winter wheat lines were grown at 4 °C for 1–18 wk, exposed to 0–2 cycles of freezing to -3 °C for 24 h, then thawed for 24 h at 3 °C, then tested for their ability to tolerate freezing to -10 °C to -17 °C. The freeze–thaw treatments resulted in increased freezing tolerance after 6–12 wk of growth at low temperatures, but had no significant effect before or after that time period. Two cycles of -3/3 °C freeze–thaw was consistently more effective than one cycle. Variation in the extent and timing of the effectiveness of the freeze–thaw treatments was found among the wheat lines, suggesting genetic variation that may be useful for prolonging freezing tolerance further into the winter months could be found in winter wheat.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 97 • No. 2