ダリヤの舌状花及び管状花比に対する日照時間及び温度の影響に就いて

抄録

Seasonal changes of numbers of flowerlets, rayflowers and disk-flowers in flower heads were observed on eighteen commercial dahlia varieties for cut flower from early June to middle November in Tokyo.
In Kinkazan, Minamino-homare and Izumi, seasonal variations of the ratios of ray-flowers to disk-flwers were rather small; in Benitsubaki, Shinpi, John, Kozakura, Baby Royal, they were very large; and in the other varieties, they were intermediate.
Six varieties were grown under short day condition in August, and were also grown under long day condition after middle September. By these treatments, it was found that numbers of flowerlets per flower head were not affected by photoperiod, but is affected by temperature.
Ratios of ray-flowers to disk-flowers were affected by both photoperiod and temperature, though degree of response was varied with varieties. Varieties were classified into the following three types according to their response to photoperiod and temperature.
1. The ratio is not affected by photopeiod, but is markedly affected by temperature……………… Kozakura type (Kozakura, Honoho).
2. The ratio is not affected by temperature, but is markedly affected by photoperiod…………………John type (Izumi, Karyu, John).
3. The ratio is affected both by photoperiod and temperature…………… Matsuno-yuki type (Matsuno-yuki).