Abstract
Varietal differences in the number of panicles per hill and in the relationship between the number of spikelets per hill and the number of spikelets per panicle on each order tiller in the rice plant were investigated. The number of panicles per hill among the rice varieties studied ranged from 18 to 30. Although this difference was due to the number of panicles on the primary and secondary tillers, it was more greatly influenced by the latter. No significant relationship was observed statistically between the number of panicles per hill and the total number of spikelets per hill. However, the number of panicles per hill showed a significant negative correlation with the number of spikelets per panicle on each tiller and also with the average number of spikelets per panicle on the hill. The slope of the regression line for the relationship of the number of spikelets per panicle on each order tiller to the number of panicles per hill was in the following order : main stem < primary tiller < secondary tiller. The varieties with a larger number of panicles per hill showed smaller differences in the number of spikelets per panicle among each tiller. The number of spikelets on the main stems showed a significant positive correlation with the number of spikelets per panicle on the primary and secondary tillers. Thus the varieties that had larger numbers of spikelets on the main stems also had large numbers of spikelets per panicle on the primary and secondary tillers.
