Plants of two everbearers (O￣ishishikinari and Shikinari) and a forcing variety (Harunoka), were forced from the 1st, Oct., 1972 to investigate the effects of photoperiods (8, 12 and 16 hour) on vegetative growth and flowering.
Leaf length (blade+petiole) was highly increased with 16 hour, while with 12 and 8 hour it was significantly dwarfed in all varieties. Similar tendency was shown in cluster length except with 12 hour that made almost the same increase as 16 hour in Shikinari and Harunoka.
No. of days for 50% bloom of the 1st flower was greatly hastened by 16 hour, especially in everbearers. Total no. of flowers was also increased with long day over 12 hour, but little difference was observed in Harunoka. In no. of clusters 16 hour was most effective in all varieties.
In seasonal changes of flowering, three apparent peaks were appeared in Shikinari with 12 and 16 hour, and in O￣ishishikinari with 16 hour. The peaks were appeared in duration of about 40 days.
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