In order to compare different section folding strength of spring maize varieties, in cold and arid regions of northwest 9 spring maize varieties as the research object, through the determination of corn base in the third section flexural strength, microstructure and by using optical microscope to observe the internodes, section microscopic indicators of vascular bundle and folding strength related analysis, research section of spring corn folding strength and stem the relationship between the microstructure. The results showed that the joint folding strength of different spring maize varieties reached a significant level. The statistical analysis on the microscopic indexes of vascular bundles showed that the variation coefficient of vascular bundle sheath thickness and epidermal cell thickness was the largest, reaching 34.8% and 23.2% respectively. The increase of the number of vascular bundles in stem segment was not conducive to the improvement of the nodule folding strength (r=-0.945**, r=-0.927**), while the increase of the mean area of vascular bundles and phloem area was beneficial to the increase of the nodule folding strength (r=0.831*, r=0.799*, r =0.733*, r=0.786*).Diameter analysis showed that the number of vascular bundles had the largest direct effect on the strength of the stem folding, followed by the thickness of epidermal cells, and the largest area of vascular bundles, the thickness of vascular bundle sheath, phloem area and other indicators also had an indirect effect on the strength of stem folding through the number of vascular bundles. Among the tested varieties, the number of vascular bundles was less, the average area of vascular bundles and phloem area were larger, the stalk folding strength was higher, and the lodging resistance was better than other varieties.
河北省现代农业产业技术体系 (玉米体系岗位专家) (HBCT2018020203);河北省科技厅项目(18226334D)；张家口市科学技术局项目(1911012C)