title: [Freezing resistance and injury indices for different cultivars of winter-spring wheat in Huang-Huai-Hai Plain. I . Comparison of freezing resistance for different cultivars of winter-spring wheat during mid-winter period].
abstract: The relationships between mortality rate and low temperature for different cultivars of winter-spring wheat during mid-winter period were identified through two-year outdoor potting experiments and indoor manually controlled freezing experiments. We defined the lethally critical temperature and the density of antifreeze capability when the mortality rate reached 10%, 20% and 50% for different cultivars of winter-spring wheat during mid-winter period. The strong-winterness wheat (Yanda 1817 and Jing 411) showed the best freezing resistance and the 50%-lethal temperatures (LT50) of these two cultivars were -21.5 °C and -21.2 °C, respectively. The freezing resistance of winterness wheat and weak-winternes wheat were worse than that of strong-winterness wheat. The LT50 of winterness wheat cultivars Nongda 211 and Nongda 5363 were -21.1 °C and -20.3 °C, while that of weak-winterness wheat cultivars Zheng 366 and Ping' an 8 were -18.5 °C and -18.4 °C , respectively. Springness wheat (Zheng 9023 and Yanzhan 4110) showed the worst freezing resistance, and the LT50 were -15.4 °C and -14.7 °C, respectively. When temperature declined to freezing injury occurred, mortality rate increment for weak-winterness wheat was the highest for each 1 °C decrease. The mortality rates of weak-winterness wheat cultivars Zheng 366 and Ping' an 8 increased by 16.8% and 25.8%, and that of winterness wheat cultivars Nongda 211 and Nongda 5363 increased by 14.7% and 18.9%. The mortality rate of strong-winterness wheat cultivars Yanda 1817 and Jing 411 increased by 15.4% and 13.1%, and that of springiness wheat cultivas Zheng 9023 and Yanzhan 4110 increased by 13.8% and 15.1%. Comparatively, if temperature decreased continuously after the occurrence of freezing injury, the weak-winterness wheat would suffer greater risk.
authors.forename: Cheng-ying
authors.initials: CY
authors.lastname: Mu
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Yang
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Ke-nan
authors.initials: KN
authors.lastname: Li
authors.forename: Dong-xiao
authors.initials: DX
authors.lastname: Zheng
mesh_terms: D000383:Agriculture; D005615:Freezing; D014908:Triticum / Q000145:classification / Q000502:physiology*