`Autumn Bliss', `Heritage' and `Redwing' were grown in a controlled environment setting at three day/night temperature regimes (30/25, 25/20, 20/15C) at either 12 or 16 hour photo periods. Vegetative (height, diameter, node number, leaf area, leaf, cane and root dry weight) and reproductive (precocity, numbers of fruiting laterals, flower number and dry weight) parameters were analyzed. Optimum vegetative growth was obtained when plants were subjected to short photoperiods (12 hrs) and cool (20/15C) or moderate (25/20C) day/night temperatures. Reproductive characteristics were enhanced when grown under long photoperiods (16 hrs) and moderate temperatures. High temperatures (30/25) reduced cane height due to a decrease in internode length with the greatest reduction occurring under long photo periods. Precocity and flowering was enhanced by long photoperiods especially at cool and moderate temperatures. This may have implications for the reproductive potential of these cultivars when grown in north temperate areas where high temperatures are common for most of the summer.
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