Relationship between stalk biomechanical properties and morphological traits of wheat at different growth stages

Four kinds of fine variety winter wheat in northern China were chosen to perform the experiments in order to study the biomechanical properties and optimal traits of winter wheat. The biomechanical properties (such as cross sectional moment of inertia, tensile strength, bending strength, shear strength, Young’s modulus and bending rigidity) and morphological traits of basal second internodes were measured at three growth stages of wheat, which were flowering stage, milk stage and dough stage. The relationship between the stalk biomechanical properties and the morphological traits of wheat were analyzed by Statistics Analysis System. It can be concluded that the main biomechanical evaluation index is bending strength at the flowering stage and is bending rigidity at the milk stage. It is also determined what morphological traits are more relative to the corresponding mechanical properties. At the flowering stage they are outside diameter, dry mass of stalk, plant height, internode distance, water content, stem wall thickness and ear mass. At the milk stage they are ear mass, outside diameter, leaf sheath height and dry mass of stalk. The partial correlation coefficients between them are different with the growth of wheat. Especially the correlation degrees between mechanical properties and water content are decreased gradually. The conclusions are the foundation to select evaluation indices for building biomechanical evaluation system.