黄淮海地区不同冬春性小麦抗冻能力及冻害指标Ⅰ.隆冬期不同冬春性小麦抗冻能力比较

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

通过两年室外盆栽和室内人工控制试验,建立了不同冬春性小麦品种死苗率与低温的定量关系,确定了隆冬期不同冬春性小麦品种死苗率达10%、20%和50%的临界低温以及抗冻能力密度.结果表明:强冬性小麦品种抗冻能力最强,半致死温度最低(燕大1817为-21.5℃,京411为-21.2℃),其次是冬性品种(农大211为-21.1℃,农大5363为-20.3℃)和弱冬性品种(郑366为-18.5℃,平安8号为-18.4℃),春性品种抗冻能力最弱(郑9023为-15.4℃,偃展4110为-14.7℃).当温度降低到冬小麦冻害发生临界温度后,温度每降低1℃,弱冬性小麦(郑366和平安8号)死苗率增量最大,分别增加16.8%和25.8%,冬性小麦(农大211和农大5363)死苗率分别增加14.7%和18.9%,强冬性小麦(燕大1817和京411)死苗率分别增加15.4%和13.1%,春性小麦(郑9023和偃展4110)死苗率分别增加13.8%和15.1%,说明冻害发生后若持续降温,弱冬性品种遭受冻害风险更大.

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 ℃ and- 21. 2 ℃,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 ℃ and- 20. 3 ℃,while that of weak-winterness wheat cultivars Zheng 366 and Ping＇an 8 were- 18. 5 ℃ and- 18.4 ℃,respectively. Springness wheat（ Zheng 9023 and Yanzhan 4110） showed the worst freezing resistance,and the LT50were- 15. 4 ℃ and- 14. 7 ℃,respectively. When temperature declined to freezing injury occurred,mortality rate increment for weak-winterness wheat was the highest for each 1 ℃ decrease. The mortality rates of weak-winterness wheat cultivars Zheng 366 and Ping＇an8 increased by 16. 8% and 25. 8%,and that of winterness wheat cultivars Nongda 211 and Nongda5363 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 springness wheat cultivars Zheng 9023 and Yanzhan 4110 increased by 13. 8% and 15. 1%. Comparatively,if tempe-rature decreased continuously after the occurrence of freezing injury,the weak-winterness wheat would suffer greater risk.