Evaluation of maize lodging resistance based on the critical wind speed of stalk breaking during the late growth stage

Abstract

Background The accurate evaluation of the stalk-lodging resistance during the late stage of maize growth can provide a basis for the selection of cultivars, the evaluation of cultivation techniques, and timely mechanical grain harvesting. In this study, the critical wind speed of stalk breaking, plant morphology, stalk mechanical strength, and lodging rate were investigated in 10 maize cultivars to identify the parameters as evaluate lodging resistance during the later growth stage of maize, and clarify the relationship with the stalk mechanical strength, critical wind speed of stalk breaking, and natural lodging rate in the field. Results The results showed that, in the late growth stage, with increasing number of days after physiological maturity, (1) the stalk lodging rate gradually increased, (2) the stalk breaking force and rind penetration strength (RPS) of the third internode above the soil gradually decreased, and (3) the critical wind speed of stalk breaking increased first and then decreased, and was highest at about 16–24 days after physiological maturity. Furthermore, the stalk lodging rate was significantly negatively correlated with the critical wind speed of stalk breaking, however was not correlated with plant height, ear height, stalk breaking force, or the RPS. Additionally, the critical wind speed of stalk breaking was significantly positively correlated with the stalk breaking force and the RPS. Conclusion This indicates that the critical wind speed of stalk breaking is a superior way to determine the stalk lodging resistance compared to traditional indicators. These results suggest that, in the late growth stage, the decrease in the stalk mechanical strength is an important reason for the decrease in the critical wind speed of stalk breaking and the increase in the lodging rate.