engleski

Effect of photoperiod, cultivar and number of lateral shoots on poinsettia

The effects of photoperiod and number of lateral shoots on vegetative growth, number of open central clusters, and percentage of fully colored bracts in five poinsettia cultivars were studied. The cultivars were grown at three different photoperiods ; under short-day period (SD, 9 h) long-day (LD, 13 h) and natural day (ND, 11-h day length from the 15th to the 31st of Oct. ; 10-h day length from the 1st to the 15th of Nov. ; 9.5-h day length from the 15th to the 30th of Nov. ; 9-h day length from the 1st to the 15th of Dec.).Vegetative growth was affected by cultivar but not by photoperiod or the number of laterals. Short-day conditions generally enhanced the opening of central cluster. Differences among cultivars were spotted in percentage of bract coloration and were greater under natural- and long-day treatments than under short-day treatment. Also in the time required for flower initiation and development, differences among cultivars were probably the reason for variations in bract coloration under same day-length conditions.

day length; poinsettia cultivars; vegetative growth

nije evidentirano