Abstract:
Imitating the regularity of temperature variation in the winter wheat field of Chifeng City,in Inner-mongolia and the northeast regions by using the freezing method.two hardier cuhivars “Norstar’’and “Mironovskaia 808’’are selected tO determine their 1etha1 temperatures.The LT20 of “Norstar” and “Mironovskaja 808”is -26.2℃ and -23.9℃ .the LT50 is-27.712 and -26.3℃ respectively in January;the freezing tolerance of the varieties in February is 1ass-hardened。their LT20 is -10.0℃ and -8.912 and the LT50 is -12.912 and -11.7℃ respectively.