Abstract

This study was conducted to determine the effects of different day lengths and daminozide on days to flower, some quality parameters and chlorophyll contents of spray chrysanthemum plants (Chrysanthemum morifolium cvs. 'Yellow Reagan' and 'White Reagan') grown under greenhouse conditions. Day length and daminozide significantly affected days to flower, stem length, stem diameter and flower numbers per stem. While stem fresh weight and chlorophyll a and b contents were affected by day length, daminozide had an insignificant effect on these parameters. Long day (LD) conditions delayed days to flower by 42 days as compared to short day (SD) conditions. SD conditions reduced stem length (84.47 cm) by almost 2-fold as compared to LD conditions (169.88 cm). Under SD conditions, the stem lengths of plants treated (3000 mg L^-1) and untreated (control) with daminozide were 79.21 and 89.73 cm, respectively, whereas under LD conditions, they were 156.33 and 183.43 cm, respectively. The flower number increased per stem both under SD conditions and with daminozide application. The numbers of flowers per stem were 13.40 and 11.87 under SD and LD conditions, respectively, and 14.11 flowers were obtained from the plants treated with daminozide, while 11.17 flowers per stem were obtained from the plants untreated with daminozide. LD conditions increased both chlorophylla (11.50 µg/mg) and chlorophyll b (5.93 µg/mg) contents as compared to SD conditions. In the study, compact and higher quality flowers with a desired stem length were obtained both under SD conditions and with daminozide application.

Key words: Chlorophyll, chrysanthemum, daminozide, long day, short day, stem length.