Effect of fluctuating temperature on growth and flowering of chrysanthemum morifolium ramat
Mortensen, L.M.; Moe, R.
Gartenbauwissenschaft 52(6): 260-263
Rooted cuttings of three chrysanthemum cultivars (cut-flowers) were grown until flowering at different day (D) and night (N) temperatures in 10 h day-1 photoperiod. Pland dry weight was not affected by decreasing N temperature from 18 to 10.degree.C while decreasing D temperature significantly reduced it. Fluctuating N or D temperature in 2-hour intervals from 10 to 18.degree.C resulted in dry weights similar to the 14.degree.C constant treatment. Plant height was increased by lowering N temperature. Time until visible colour of the first flower was delayed 3 to 10 days in the different cultivars when N temperature was decreased from 18 to 10.degree.C. Reducing D temperature from 18 to 14.degree.C delayed flowering 5 to 10 days. Fluctuating N temperature gave the same effect on flowering as constant 14.degree.C. Fluctuating D temperature reduced the time until flowering compared to 14.degree.C constant. It is concluded that fluctuating temperatures is of small interest at least for this species.