Abstract
In submerged direct seeding such as hill seeding and row seeding, lodging was not caused easily compared with broadcast seeding. Not only deep rooting but also physical characteristics of the basal culm were considered to contribute to lodging resistance. Then, we examined the correlation of lodging resistance with the rooting behavior and physical characteristics of the basal culm in 14 rice cultivars direct seeded in a flooded paddy field. As a result, deep rooting, the section module and breaking strength of culm with leaf sheaths were significantly correlated with lodging resistance regardless of seeding depth. In addition, the standardized partial regression coefficient and partial correlation coefficient between lodging resistance and breaking strength of culm with leaf sheaths was higher than lodging resistance and deep rooting. These results suggest that lodging resistance in rice cultivated by submerged direct seeding such as hill seeding and row seeding was more closely correlated with the physical characteristics of the basal culm than with deep rooting.
