Growth, physiology and flowering of chrysanthemum var. Punch as affected by daminozide and maleic hydrazide

Growth retardants have been proven to prevent excessive stem elongation and reduce internode length in plants by inhibiting the effect of cell division and enlargement of cell in plants. This study was aimed to evaluate the effect of concentrations of daminozide and maleic hydrazide on growth, physiology and flowering of chrysanthemum cultivar Punch under protected condition. The treatments composed of two growth retardants: daminozide at four different concentrations (1000, 1500, 2000 and 2500 ppm) with three frequencies (7, 14 and 21 days after darkening) and maleic hydrazide at three different concentrations (500, 750 and 1000 ppm) with two frequencies (7 and 21 days after darkening) along with control (no spray given). Hence based on the results obtained, it can be concluded that single application of daminozide at 2500 ppm at seven days after darkening reduced the plant height at considerable height (34.33, 83.33 and 103.58 cm) at critical stages and improved total leaf area (1694.55 and 1745.27 cm2) at bud appearance and peak flowering stage and showed earliness in flowering and days to harvest (44.72 and 81.33 day), increased pedicel length (5.87 cm), cut stem girth (3.24 cm), stem fresh weight (68.00 g/stem) and chlorophyll (1.93, 2.53 and 2.80 mg/g) and soluble protein content (65.66, 72.33 and 80.66 mg/g) at critical stages. Increased cut stem yield (77.34 stems/m2) and improved vase life (12.50 day) were also recorded. This may be recommended to improve growth and flower quality of ‘Punch’ chrysanthemum under greenhouse conditions. Key words: Chrysanthemum, daminozide, maleic hydrazide, growth, flowering.