Effect of photoperiod and chemical retardants on growth and flowering of pot mums (<i>Dendranthema grandiflora</i> Ramat)

Abstract

Potted plants of chrysanthemum varieties namely Arun Kumar and Sweta Singar, were exposed to 8 h light and 16 h darkness and natural photoperiod, and spayed with maleic hydrazide (1000 and 2000 ppm), cycocel (1500 and 3000 ppm) and control (distilled water) in factorial complete block design with three replications. The results revealed that controlled photoperiod of 8 h light and 16 h darkness was found significantly superior over natural photoperiod with regard to minimum internodal length (2.85 cm), days to floral bud initiation (98.88), maximum flowering duration (23.14 days), flowers plant-1 (189.50), flower diameter (2.72 cm), fresh weight of flower (1.16 g) and vase life (14.86 days). Among growth retardants, maleic hydrazide (2000 ppm) significantly recorded minimum plant height, maximum branches plant-1 (18.85), flowering duration (25.25 days), flower diameter (2.95 cm), flowers per plant-1 (194.90) and weight of flower (1.20 g), while, maleic hydrazide (1000 ppm) recorded minimum internodal length (2.65 cm) and maximum vase life (18.00 days). The cv. Arun Kumar under controlled photoperiod recorded minimum internodal length (2.38 cm) and early floral bud initiation (91.04 days), however, maleic hydrazide (2000 ppm) recorded maximum flower diameter (4.05 cm), fresh weight of flower (1.53 g) and vase life (18.50 days). cv. Arun Kumar under controlled photoperiod treated with CCC-3000 ppm showed the best performance in recording the maximum number of flowers plants-1 (138.00) during first fortnight of flowering.