Comparison of net photosynthetic rate in leaves of soybean at different yield levels

Total nine soybean (Glycine max (L.) Merr.) cultivars divided into three yield levels were planted under the same environmental condition.The net photosynthetic rate was measured by LI-6400 portable photosynthesis system;the chlorophyll content and the specific leaf weight were measured with the regularmethod.The results showed that the specific leaf weight,chlorophyll content and net photosynthetic rate of high yield varieties were higherthan those of low yield varieties.The yield had a significantly positive correlation with the net photosynthetic rate.As the results of modern technology improvement,the net photosynthetic rate could be measured quickly and exactly,as the selection index of high yield soybean,the netphotosynthetic rate would be putinto effective use in soybean breeding in the future.