Abstract
Three early wheat cultivars of west Japan, Norin 26, Norin 61 and Omasekomugi, sown in autumn, were compared regarding tiller appearance and heading. The difference in maximum tiller number among three cultivars was small; whereas the differcnce in headed tiller number was large, the largest in Omasekomugi and smallest in Norin 26. This difference was due to the difference in heading ratio of the secondary tillers, not to their appearance ratio. There was a certain period when a negative correlation coefficient was observcd between the appcarance date of the secondary tillers and their heading ratio. The appearance date of the secondary tillers with a heading ratio of 80% or 50%, was about 10 days later in Omasekomugi. The number of the secondary tillers appeared till this date was much larger in Omasekomugi than in the other two cultivars. As a result, there was a difference among three cultivars in the number of headed tillers. The varietal difference was small among the cultivars in the relation between the heading ratio and the increment of dry weight of the secondary tillers in March. In contrast significant differences was observed in the increment of dry weight and of culm length of the secondary tillers in March among the three cultivars. The result suggests that these differences resulted in the difference among the cultivars in the heading ratio of the secondary tillers.
