The Mechanism Of Hybird Soybean Photosynthenie In Physiological And Biochemical

In recent years, with the improvement of people’s living standard, the demand for soybean is on the increase. Soybean acreage is reducing in our country. And our soybean market is full of imported soybean. Thus, increasing the yield of soybean become a burning question. The hybrid soybean will be available to solve this problem. But, we may meet another problem that the breeding of hybrid soybean is very cumbersome. This process needs a lot of manpower, material resources, and a long period. So hybrid soybean has not yet been popularized on a large scale. Photosynthesis is the basis of crop formation. Many studies have shown that a variety with strong photosynthetic capacity will have high yield. We can start with photosynthesis to study the photosynthetic superiority of hybrid soybean and the relation between photosynthesis and yield. I chose the hybrid soybean with yield gap and its parental lines as materials to find the relationship between photosynthesis and yield through studying the photosynthetic physiology and biochemical mechanism of hybrid soybean, in order to provide a theoretical basis for the breeding of hybrid soybean.1Three types of hybrid soybean and their parents were measured by photosynthetic analyzer to get the photosynthetic performance indexes in such in five stages as seedling stage, full-bloom stage fruiting period, seed filling stage and mature stage including the change regularity of net photosynthetic rate, transpiration rate, water use efficiency, intercellular CO2and stomatal conductance. The results showed that each index had different change rule in different period. In fruiting period, the net photosynthetic rate, transpiration rate, intercellular CO2and stomatal conductance of hybrids were higher than their three parental lines. Water use efficiency of hybrid had no superiority in the whole growth period. In other periods, the photosynthesis was not obvious.2Through conducting correlation analysis on the relationship between yield and photosynthetic indexes of soybean in each period, especially the relationship between yield and net photosynthetic rate of soybean, I knew that during the whole growth period except the seedling stage, there was a positive correlation between yield and net photosynthetic rate; in the seedling stage, there was a significant positive correlation between net photosynthetic rate and transpiration rate; in the fruiting period, there was a significant positive correlation between net photosynthetic rate and water use efficiency. Other photosynthetic indexes had different correlations in different periods. Through conducting correlation analysis on the relationship between yield and photosynthetic indexes of the hybrids in different periods, I knew that in full-bloom stage, fruiting period and seed filling stage, there was a positive correlation between net photosynthetic rate and yield. The maximum correlation occurred in the full-bloom stage. So the research on physiological and biochemical indexes in full-bloom stage, fruiting period and seed filling stage was necessary.3Through the experimental study on change rule of hybrid soybean chlorophyll content, Hill reaction activity, soluble sugar content, soluble protein content in full-bloom stage, fruiting period and seed filling stage, I concluded that the chlorophyll content, Hill reaction activity of hybrids were higher than that of their parents in fruiting period and seed filling stage. The soluble sugar content of them in fruiting period was higher than the three parental lines, while the change of soluble protein content was small with slight advantage. Through conducting correlation analysis on yield, chlorophyll content, Hill reaction activity, soluble sugar and soluble protein of the hybrids, I concluded that there was a positive correlation between the yield and all the other indexes in full-bloom stage; the maximum correlation between yield and chlorophyll occurred in the fruiting period; there was a positive correlation between the yield and soluble sugar in seed filling stage.4In order to explore the plant type of high-yield hybrid soybean, I conducted main agronomic character analysis on hybrid soybean and three parental lines. The analysis of variance indicated that, the yield of hybrids was higher than that of the three parental lines and reached significant level. Through conducting correlation analysis on the relationship between net photosynthetic rate and main agronomic traits of hybrids, I reached the conclusion that there was a close relationship between net photosynthetic rate and grain weight per plant,100-grain weight, as well as economic coefficient.