Abstract
In edible canna (Canna edulis Ker–Gawl.), the causal factors of lodging were analyzed in relation to the morphogenesis of aboveground parts using mathematical models. The projected side–view area of aboveground parts which reflects growth vigor was large and determined by the three parameters : plant height, width of stock base and stand angle. The causal factors of lodging were related mainly to morphogenic characters of the large aboveground parts. They were ascribed to the large projected area in terms of external force such as wind and to the own weight moment in terms of internal force which was added by its aerial weight. The increase in stem inclination in the late growth stage was due to the swelling of rhizomes. From the viewpoint of yield formation, it was concluded that the shortening of plant height to about 2 m at the late growth stage was preferable for a high yield. This shortening mitigates 10–20% of external force and about 50% of internal force from the risk of lodging after the middle growth stage.
