Relationship Of Canopy Temperature With Grain Yield, Water And Nitrogen Use Among Various Genotypes Of Dryland Winter Wheat

Drought and water shortages in agricultural production are the main constraints, and improving crop water and fertilizer efficiency use is the core of dryland agricultural production, which play a variety of biological and genetic potential is the most potential, identify water-saving measure drought and high water and fertilizer use efficiency is the variety of indicators on the hot spots. Canopy temperature in the dry crops as a diagnosis and determine whether or not drought-resistant crops genotype of the research has long been widespread concern that drought-resistant crops has gradually become an important basis for genotype choice, and crop water use are closely related. This study in Gansu Province and Gansu dry jointing stage limited irrigation conditions, with 19 genotypes of winter wheat dryland in the northern regional trial genotypes and 21 genotypes of USA for the tested materials, in the 2006-2007,it study wheat grain filling stage canopy temperature and yield, water use efficiency, the relationship between the use of nitrogen in order to provide the basis for drought-resistant water-saving and efficient use of nitrogen fertilizer wheat varieties selection. The main results of study are:1. Either dry or limited supplementary irrigation, 40 different genotypes of winter wheat production, water use efficiency (WUE), irrigation period canopy temperature (CT), N fertilizer physiological efficiency (NPE)reached significant levels. The average yield of the dry is 2883.6 kg /hm2,and the coefficient of variation was 16.74 %, irrigation yield 3315.1 kg/hm2, and the coefficient of variation is 18.47%; filling the late dry CT 36.02℃, the coefficient of variation 3.08%, irrigation CT 34.72℃, the coefficient of variation 3.49% Water use efficiency WUE dry 8.05 kg /hm2·mm, the coefficient of variation 16.46%, irrigation 7.88 kg/hm2·mm, the coefficient of variation 17.39%; N fertilizer physiological efficiency, dry as 24.13 kg/kg, the coefficient of variation 12.58%, Irrigation 24.37%, 14.01% coefficient of variation. Research shows that different genotypes of wheat field was not obvious differences in water consumption, and the grain yield and a significant WUE between the linear regression (P<0.001), WUE for each additional 1 kg/hm2·mm, output increased 358.4-440.05 kg/hm2. Despite the high water use efficiency to consume more varieties of soil moisture, but the rate of increase in water consumption was significantly lower than the rate of increasing in output, then the results of water use efficiency improved significantly.2. There is a high degree of differentiation phenomenon on genotypes of wheat in grain filling stage canopy temperature, and the differences could be reflected in the production and difference of water use efficiency. Whether irrigation or dry processing, whether early or mid-or filling in the latter part of dryland winter wheat yield, water use efficiency and canopy temperature was a very significant negative correlation (R2=0.271-0.524), and with the acceleration of filling process or procession of reproductive age, the relevance increases. With the reduction of CT ,the production increase. the low canopy temperature has high yield, and the high canopy temperature has low yield. Filling in the latter part of each canopy temperature increased 1℃, dry lower yield 260 kg/hm2, irrigation reduced 404 kg/hm2, dry WUE fell 0.69 kg/hm2 mm., irrigation WUE fell 0.87 kg/hm2 ? mm. CT of the appropriate period for filling the late noon to 13:00 to 15:00 in suitable.Whether in dry or filling conditions, eight observation on the CT value and yield has significant negative correlation, particularly after the mid-filling some genotypes of wheat canopy temperature maintains higher consistency, partial low varieties canopy temperature with higher yields and water use efficiency. Therefore, filling the latter part of CT in the evaluation of wheat production and water use efficiency has higher reliability which can be as a field of choice of targets.3. With dry conditions filling stage (from May 20 to June 6) four times in the CT average of indicators, calculated by the Euclidean distance, will try again for the 40 varieties divided into three categories, Class I for Intermediate, a total of Genotypes of 29; Class II for Pianleng type, only one species; Class III warmer for a total of Genotypes of 10. Compare with the middle-class I, the CT of cooler Class II below 3.08℃, production,WUE increased 895.94 kg/hm2,2.48kg/hm2·mm, the CT of warmer Class III increase 1.83℃, production,WUE reduce 611.08 kg/hm2,1.74 kg/hm2·mm.That means with lower canopy temperature of the wheat has a high water use efficiency and productivity in filling stage.4. It is very different between genotypes of wheat grain and straw N-quality content, but the difference was not obvious between dry and limited supplementary irrigation. An average of 40 species, including grain for the N 2.84%~2.90%, the variety of the coefficient is 8.31%~9.08%;straw-N is about 0.9%, the coefficient of variation is 26%~28%, that is different genotypes of wheat on the N-use of main difference in the performance of straw N to N the transfer of grain. Weather dry or limited supplementary irrigation, N different genotypes of wheat grain output and WUE has significant positive correlation, the correlation coefficient were 0.745,0.649, With the N grain output increasing, the water use efficiency increase corresponding. With the same production,WUE is similar to the changes, wheat grain filling stage canopy temperature and grain absorption of N are also significant negative correlation with the increase in the filling stage CT, wheat grains absorbing the number of N decrease, CT increased 1℃, grain N output reduced about 7~9 kg/hm2. The results further show that filling period of strong temperature than the varieties have a high metabolism physical activity and a strong ability to root absorption of nitrogen, nitrogen accumulation of grain in large, high transpiration rate, water use, N fertilizer use and lower The canopy temperature linked to the level of canopy temperature reflect a different genotypes of wheat in the differences in the use of resources, the cultivation of scientific and reasonable measures are convenient and more accurate indicator.Winter wheat grain filling stage of the canopy temperature and yield,water use efficiency,N fertilizer use are close relation, canopy temperature can be used as screening drought-resistant water-saving and high N fertilizer efficiency as an important indicator species.