Effectiveness of Plant Growth Regulators on Growth and Development of 'Revert' Chrysanthemum

Influence of growth retardants on growth and development of Revert chrysanthemums (grown as cut flowers) was investigated during one-year trial. Experiment was conducted on a family farm near Đurđevac, Croatia, in a plastic greenhouse. Two growth retardants, Cycocel and Alar 85, in three different concentrations were used. Cycocel was used in the concentration of 0, 2% ; 0, 3% and 0, 4% and Alar 85 in the concentration of 0, 1% ; 0, 2% and 0, 3%. Plant height, number of flowering shoots and number of flowers per plant were measured. Results have shown that growth retardants reduced the plant height. However, there was no significant difference in number of flowering shoots and number of flowers per plant regardless of sort of growth retardant or concentration that was used. Treatment with Cycocel in concentration of 0, 3% resulted in plants that were 6% shorter than the control. The same concentration of Alar 85, resulted in 13% shorter chrysanthemum plants, compared with the control. There was statistically significant difference in plant height between concentrations of growth retardant that were used: plants treated with Cycocel in concentration of 0, 3 and 0, 4% were for 4% shorter compared with plants treated with 0, 2% concentration (there was no significant difference in height between plants treated with 0, 3% and 0, 4% Cycocel). Plants treated with Alar 85 in concentration of 0, 2% and 0, 3% were shorter for 4% and 6% respectively, compared with those treated with 0, 1%-concentration of Alar 85 (there was no significant difference in height between plants treated with 0, 2% and 0, 3% of Alar 85).