EFFECT OF NIGHT BREAK DURATION AND PACLOBUTRAZOL ON GROWTH AND FLOWERING OF DENDRANTHEMA GRANDIFLORA POT PLANT PRODUCTION

Document Type : Original Research Article

Authors

Horticulture & Landscape Dept., Agric. Coll., Tikrit Univ., Iraq

Abstract

The experiment was conducted in Tikrit city, Iraq during the period from May to December 2019 on Dendranthema grandiflora. The objective of this study was to evaluate the use of night break to prolong marketing period of the plant. Two factors were included, the first factor was night break (NB) at five levels (natural day, 5 seconds (flash light), 30, 60 and 120 minutes) starting at 10:00 p.m. for one month. The second one was spraying paclobutrazol at three levels (0, 500, 1000 mg l-1). The experiment was designed as split plot design, night break was set in the main plot. The results showed that NB had significant effect on values of vegetative growth characteristics. It also delayed the date of initiation and opening of the inflorescences. The treatment of 120 minutes had highest number of days to initiation and opening of flower (167.73 and 183.55 days, respectively), while natural day treatment gave lower number (133.25 and 165.73 days, respectively). The treatment of paclobutrazol at 1000 mg l-1 concentration gave lowest plant height: pot ratio and highest plant diameter (1.25 and 56.60 cm, respectively). Highest shelf life was 45.10 days at the treatment of interaction between night break of 120 minutes and spraying with paclobutrazol at 1000 mg l-1.

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