Study On Canopy Temperature Of Soybean With Different Genotype

In order to find out whether canopy temperature of soybean germ plasm materials exist difference, using infrared radiation thermometer to determine canopy temperatures of different genotype soybean germ plasm resource, at the same time, determined partial physiological characters of functional leaf and microclimate Daily change of field in the filling-time seed(include air temperature, relative humidity and illuminace)and yield of every variety. The results as blew:1. The canopy temperatures of different soybean varieties were different, some varieties had a lower canopy temperature than CK regarded as cold soybean, such as Fendou55,JiNF58. and some varieties had a higher canopy temperature than CK regarded as warm soybean, such as 94101, Dongda2.2. There was a obvious difference among different temperature type soybean germ plasm in external expression and inner physiological activity of plant. The functional period of leaf of cold soybean was longer than warm soybean, and the cosenescence progress of leaf was also slower than warm soybean; Net photosynthetic rates, transpiration rate, chlorophyll content of functional leaf had been keeping high; soluble sugar content was higher than warm soybean; and soluble protein content and NR activity were markedly higher than warm soybean; Protective enzyme system such as CAT activity and SOD activity were better than warm soybean in the whole growth period; MDA content accumulation rate was slower than warm soybean with the growth moved. According to these we thought the relation between temperature type and quality of physiological characters of function leave was close, Grey Correlative Analysis showed that the indexes that closely related to canopy temperature in order MDA content, soluble protein content, CAT activity, SOD activity, NR activity, soluble sugar content and chlorophyll content.3. Field microclimate of different genotype soybean was markedly different. The change trend of air temperature and illuminance was up and then down, and moisture was opposite. The most obvious difference of field microclimate appeared 13:00-15:00 after noon, the biggest difference value of air temperature was 1.85℃after weighted average, the relative humidity was 2.97% and the illuminance was 5.35klx. In the whole filling-time seed, the inner-plant air temperature of cold soybean was lower, the inner-plant moisture was higher and the inner-plant illuminance was smaller than warm soybean.4 Variance analysis of different genotype soybean varieties showed that yield of different soybean varieties existed significant difference, JiNF58's yield was the maximal. The correlation analysis between yield and physiological characteristics that formed yield showed that the physiological characteristics could obviously effect yield were in order no. of pods per plant, no. of grains per plant, no. of section of main stem, weight per 100 grains, no. of branches and height of plant, their correlations were 0.540,0.390,0.340,0.330,0.090 and 0.030,respectively. The path analysis indicated ulteriorly that the direct selection effect of no. of grains per plant and weight per 100 grains were maximal, So we should take no. of grains per plant and weight per 100 grains as important indexes when we choose and breed soybean varieties.