Canopy Temperature Depression In Relation To Drought Resisitance And Water Saving In Different Winter Wheat

The short in water resource has become "the bottleneck" of sustainable development in China. The main contents based on wheat breeding for drought resistance and water saving has become the key of Chinese water saving agriculture technology research. However, it was controled by polygene,has extremely distinctive feature,and influened by environment easily environment,and the availability and the reliability of biologic water saving agriculture technology research was sorestricted in a long period。In order to break and eliminate the influence,two way were used by wheat breeder:The first solution to this problem is screening and utilization of choiceness germplasm resource, the second solution to this problem is the balance strategies of character:drought resistance and water saving, high yield and good quality. The top importance of biologic water saving research was how can we screening and utilization the germplasm resources and filial generation.Expression of physiological signal is the most direct and instinctive reflection of water stress in the three type index:agronomy characteristics,physiological and biochemical characteristics and genetic gene. Canopy temperature depression(CTD),as a identification and screening of Drought Resistance Appraisal Standards on Wheat,was receiving more and more attention.A large number of researchment proves that CTD can be used to predict the yield, crop water deficit and irrigation index, besides, it has a application prospect of from screening of drought resistance appraisal standards on wheat breeding to identification of adaptation to drought of different cultivar.Studies were conducted to ascertain the examine parameters(stage and time) ,determines methods and influence factors of Canopy Temperature Depression (CTD); the relationship between CTD with drought resistance and water saving by convenient apparatus. Thirty wheat cultivars were grown under dryland and irrigation in two years, associated laboratory examination under water stress. the feasibility and judge standard that CTD as a potential selection criterion screening and identification indexes for drought resistance and water saving were researched and validated. In order to reveal physiological mechanisms,root growth and photosynthetic physiological characteristics of wheat varieties of different type were studied.The results were as follows:(1). Different genotpes cultivar exhibited great differences in CTD under each Treatment. CTD can be determined on 13:30-14:00P.M. in wheat Flowering Stage by infrared temperature instrument collocation of exactitude thermometers.The dryland CTD average was 7.03℃, ranging from 5.6℃to 8.5℃, standard error 0.83℃; and the irrigation CTD average was 8.81℃, ranging from 7.8 to 10.3℃, standard error 0.77℃.The CTD was drastically correlated with the yield ,drought resistance index(DI) and water use efficiency(WUE) under each Treatment. This indicated CTD was a signal of physiological expression of winter wheat, which can be a selection criterion in winter wheat of drought resistance and water saving. The genetic was higher drought resistance if it's CTD was greater than 7.86℃, the genetic was also higher water saving if it's CTD was greater than 9.58℃. The results indicated that the method was reliable, low costs and convenient, can be used by more and more foundation wheat breeding units。(2). CTD was the directly expression of physiological reaction of winter wheat under water stress. Because of the midnap of photosynthesis was lower under irrigated treatment, effects of higher temperature and light on genetics of water saving than others, Consequently, photosynthetic rate, transpiration rate and water use efficiency were higher than others, ultimately, CTD expression is partial to height; Because of powerful roots system of higher drought resistance genetic under dryland treatment, water supplying is sufficient, Results show that only little decrease of photosynthesis rate, stomatal conductance(Gs),intercellular CO2 concentration(Ci) and transpiration rate (Tr), relationship between source and sink was harmonious, CTD expression is partial to height too.(3). Drought resistance was a complex concept. In this field test,the DI and WUE has great difference under irrigated treatment, however, it has much more consistent between DI and WUE under dryland treatment because of limited water supply.the water saving of drought resistance genetics was indeterminate, the drought resistance of water saving genetics was yet indeterminate. Definition of drought resistance and water-saving has been enriched.Overpass this research, a scientifically,simple and convenient screening and utilization index of drought resistance and water saving was ascertained ,it will contribute to wheat breeding.