Different wheat varieties were studied in Guiyang city to understand how they photosynthesize under drought conditions. The researchers found that the photosynthetic indexes varied among the wheat varieties due to differences in their development. They also discovered that high intercellular CO2 concentration was linked to higher grain weight and yield during the grain filling stage. The varieties Mianmai 45, Chuanmai 43, Chuanmai 42, and Qianmai 16 showed high intercellular CO2 concentration, good yield, and strong drought resistance.