Research Of Cold-Resistance Change Mechanism In Different Growth & Developing Period And Drought Stress In Wheat

In order to study Cold-Resistance change mechanism of wheat in different growth & developing period and the mechanism when it suffer drought stress, some cultivated varieties of Huang-huai wheat area were selected. Compare Logistic equation and Refrigeration method in lab, we calculated the Semi lethal temperature of wheat during different period in 2011 and 2012.Analysis showed that:different varieties showed the same rule of cold hardiness during the whole period. The cold hardiness in seedling period is strong. After a period freezing exercise, the cold hardiness became the strongest. As the temperature increased, the cold hardiness became significantly weaker.Jimai22, Yannongl9, Liangxing66, Wanmai38 has showed a good ability of cold hardiness in the two years. Yumai1 8, Yanzhan4110 has showed a weak ability of cold hardiness. This result is the same as they showing in the field production.With global warming, the frequency of extreme weather, The demand of wheat cold hardiness ability is higher and higher. The current production of the main varieties of cold resistance is superior to some old varieties of cold hardiness.Under drought condition, the cold resistance in the whole growth period of wheat was significantly lower than drought condition, over-wintering stage biggest declines, with an average of 4.91 ℃, turning green period was the minimum, jointing stage in the middle. Zhengmai9023, Wanmai38,Xinmail8, Jimai22, Yannongl9, Zheng366 wheat has good cold resistance in over-wintering stage,LT50 located at-7.60℃～-5.84℃. In over-wintering stage, turning green period and jointing stage, each type in the process of cold hardiness steady declined, no variety rate decrease significantly beyond the other varieties.Besides Zheng9023, cold hardiness of semi winter varieties slightly better than spring varieties, but there are no variety showed obvious advantages between semi winter varieties. It means that under the condition of drought stress, no effective potential of varieties of cold hardiness, Semi winter varieties and spring varieties are all easy suffer freezing damage.