Cold hardiness-informed budbreak reveals role of freezing temperatures and daily fluctuation in a chill accumulation model.

Autor:	North MG; Department of Plant and Agroecosystem Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA., Workmaster BA; Department of Plant and Agroecosystem Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA., Atucha A; Department of Plant and Agroecosystem Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA., Kovaleski AP; Department of Plant and Agroecosystem Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
Jazyk:	angličtina
Zdroj:	Journal of experimental botany [J Exp Bot] 2024 Oct 16; Vol. 75 (19), pp. 6182-6193.
DOI:	10.1093/jxb/erae287
Abstrakt:	Fundamental questions in bud dormancy remain, including what temperatures fulfill dormancy requirements (i.e. chill accumulation). Recent studies demonstrate freezing temperatures promote chill accumulation and cold hardiness influences time to budbreak-the phenotype used for dormancy evaluations. Here we evaluated bud cold hardiness and budbreak responses of grapevines (Vitis hybrids) throughout chill accumulation under three treatments: constant (5 °C), fluctuating (-3.5 to 6.5 °C daily), and field conditions (Madison, WI, USA). Chill treatments experiencing lower temperatures promoted greater gains in cold hardiness (field>fluctuating>constant). All treatments decreased observed time to budbreak with increased chill accumulation. However, perceived treatment effectiveness changed when time to budbreak was adjusted to remove cold acclimation effects. Among three classic chill models (North Carolina, Utah, and Dynamic), none was able to correctly describe adjusted time to budbreak responses to chill accumulation. Thus, a new model is proposed that expands the range of chill accumulation temperatures to include freezing temperatures and enhances chill accumulation under fluctuating temperature conditions. Most importantly, our analysis demonstrates that adjustments for uneven acclimation change the perceived effectiveness of chill treatments. Therefore, future work in bud dormancy would benefit from simultaneously evaluating cold hardiness. (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
Databáze:	MEDLINE
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