Maize Plant Morphology Affects Resistance to Stalk Breaking by Affecting Plant Stress

The critical wind speed for stalk breaking is a direct and rapid method for evaluating stalk-breaking resistance. Maize lodging resistance is determined by the plant's wind-induced stress and the stalk's mechanical strength, yet the factors influencing plant stress remain unclear. This study analyzed the quantitative relationship between plant leaf area, weight, and stalk base torque by implementing different leaf-cutting and ear-removal treatments. The key factors affecting plant stress under varying wind speed conditions were identified. Results indicated that the critical wind speed for stalk breaking significantly increased following leaf cutting and ear removal. Under different wind speed conditions, stalk base torque exhibited a significantly negative correlation with the critical wind speed for stalk breaking, with the strongest correlation observed at U = 14.6 m s^-1. At this wind speed, every 1 m² increase in leaf area resulted in a torque increase of 6.7 N m and a decrease in critical wind speed for stalk breaking by 17.5 m s^-1. Similarly, every 1 kg increase in plant fresh weight led to an 8.1 N m torque increase and an 18.3 m s^-1 decrease in critical wind speed. Additionally, every 1 m increase in the height of the center of gravity resulted in a torque increase of 13.3 N m and a 22.9 m s^-1 reduction in critical wind speed. Regression analysis revealed that changes in critical wind speed for stalk breaking were primarily influenced by leaf area and plant fresh weight, which accounted for 80.6% of its variation. The effects of plant fresh weight and leaf area on torque varied under different wind speed conditions. In conclusion, maize leaf area, fresh weight, and center of gravity height influence the critical wind speed for stalk breaking by altering plant torque in a wind environment.