Increasing wall thickness is more effective than increasing diameter for improving breaking resistance of rice internode

Increasing internode breaking resistance is one of the primary targets for improving stem lodging resistance of rice in a breeding program. In this paper, we evaluated the relationships among breaking resistance, dry matter per unit length and related morphological traits (diameter and wall thickness) of rice internode by using the data extracted from published articles. Scatter plot and linear regression analyses showed that internode breaking resistance could slowly (210 g cm), moderately (551 g cm) or rapidly increase (1,254 g cm) with increasing dry matter per unit length of internode (10 mg cm–1). The rapid increase of internode breaking resistance with increasing dry matter per unit length of internode was accompanied by relatively rapid increase in internode wall thickness but relatively slow increase in internode diameter. These suggest that a greater improvement in breaking resistance of rice internode can be achieved by increasing dry matter per unit length of internode combined with increasing investment of the dry matter into enhancing internode wall thickness.