| Previous studies have indicated that there is difference of the canopy temperature among different wheat genotypes after anthesis. The genotypes that have lower canopy temperature is named cold type wheat (CTW) and which have higher canopy temperature is named warm type wheat (WTW) in same ecological environment. There are differences of the characteristics of physiological and bio-chemical,and anatomic structure of leaves between the CTW and WTW genotypes. The difference of the canopy temperature of two types was not affected by the draught and rainy conditions. There are rarely reports about the N and P nutrition of CTW and WTW under different fertilization conditions. So we studied the difference of some characteristics between CTW and WTW during milk~filling using wheat genotypes Shaan229,Xiaoyan6,RB6,NR9405 and 9430 as tested crops. Shaan229,Xiaoyan6,RB6 are CTW,and NR9405 and 9430 are WTW. Field experiments and pot experiments were conducted from 2000 to 2004 at the Agricultural Experimental Station of Northwest A&F University, Yangling, Shaanxi Province, China. It is a sub-humid area susceptible to drought. Each variety received four fertilizer treatments: CK (no fertilizer), N fertilization (237.0 kg/hm2 N), P fertilization (176.25 kg/ hm2P2O5) and NP fertilization (237.0 kg/hm2 N plus 176.25 kg/ hm2P2O5). The treatments (variety×fertilizer) were factorially arranged in a 5×4 randomized complete block design. Each treatment was replicated three times. The soil is classified as Eum-Orthic Anthrosol, equivalent to an Udic Haplustalf in the USDA system. The main results showed as follows: 1. The temperature type of varieties could not be reversed with the change of fertilization environment. At the grain filling stage, the canopy temperature of CTW are 0.5～0.9℃lower than those of WTW in the different fertilizer treatments. The canopy temperature of winter wheat had a negative relationship with the chlorophyll content, water-soluble protein content, transpiration rate and net photosynthetic rate of the flag leaves. 2. Compared to WTW, CTW have higher rate of dry matter accumulation before anthesis and assimilation after it, and longer filling stage in different fertilizer treat. The supply rate to grain dry weight of the assimilation of CTW is 11.5% higher than that of WTW after anthesis. But the output of reserves in the vegetative organs before flowering of CTW is lower during filling stage, so the dry matter residues of functional leaves are higher than those of WTW at maturity. 3. The N percent content of the top three leaves of CTW are higher than that of WTW under different fertilizer conditions. The N accumulation of the CTW leaves are 17.5%, 20.2%, 37.3% and 57.6% higher than that of WTW under CK, P, N and NP treats conditions separately before flowering. The N uptake amount of CTW are 168.6%,144.6% and 217.4% higher than that of WTW in P, N and NP treats conditions after anthesis. The supply rate to the grain of CTW is significantly higher than that of WTW. There are more N residues in the leaves of CTW at maturity. 4. The flag P accumulation in the CTW flag leaves are 4.55%, 29.0%, 23.1% and 21.4% higher than that of WTW, and the P accumulation in the ears are 22.0%, 22.1%, 33.1% and –4.55% higher separately in CK, P, N and NP treats at anthesis. The P uptake amount of CTW is higher than that of WTW after flowering, and the difference is most significantly in the NP treatment. The supply rate of P absorbed after flowering of WTW to the grain is very low along with its characteristics of pre-maturity. The output of leaves P storage before flowering is increased after fertilization. It indicted that there are stronger activity of P absorption and translocation, which is agree with the higher physiological activity of CTW leaves. In the maturity, seed P accumulation rate of CTW are 6.27%, 11.19%, 18.51% and 50.72% higher than that of WTW, and P residue in the vegetative organs are 10.13%, 12.06%, 22.22% and –3.81% lower than that of WTW in CK, P, N and NP treats separately. 5. The increase rate of effective ears number/hm2, grain number/ear, weight/1000 grains and yields of CTW are all bigger than those of WTW after fertilization. The CTW genotypes are more response to the fertilization. The agronomical N use efficiency is significantly higher than those of WTW. The P harvest rate is higher than that of CTW, but physiological N use efficiency is lower owing to higher uptake rate and higher residue in the leaves after flowering. 6. The difference of canopy temperature was not changed by the fertilization, but the canopy temperature of one genotype can be affected by fertilization. Nutrient stressed plants (CK) had higher canopy temperatures compared to well-fertilized plants (NP). Which agree with other environmental stress, such as water stress. So we could use canopy temperature as an indicator of wheat nutritional conditions, and used in the effective fertilization.
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