Abstract
Using selected marketable strains of Oenanthe javanica (Blume) DC., the effect of the photoperiod on the growth of ‘Aomori-kei’, ‘Sendai-kei’, ‘Shimane-midori’ and ‘Miyagi VWD 1’ was investigated. Nursery shoots were planted in plant boxes on October 6, and grown under natural ambient temperature and a natural photoperiod. From November to March, plant boxes were set in a greenhouse in which a minimum temperature of 10°C and an 8- or 24-hr photoperiod were maintained. Runner development was not affected by photoperiod. Elongation of the basal internode was facilitated by 24-hr photoperiod, especially in ‘Sendai-kei’ and ‘Aomori-kei’. Late transfer to the greenhouse promoted elongation of the internode, and diminished differences between the photoperiods and strains, respectively. Flower buds were formed only under the 24-hr photoperiod. The results show that marketable O. javanica plants with short internode will be harvested when plants are grown under a short photoperiod without chilling. Though retarding runner development would be labor saving in preparation for shipment, runner development could not control by photoperiod.
