MANIPULATION OF PLANT GROWTH REGULATORS AND NON-INDUCTIVE PLANT ENVIRONMENT TO CONTROL PLANT HEIGHT OF FACULTATIVE SHORT DAY ORNAMENTAL ANNUALS

Abstract

Seeds of Facultative SDPs (Zinnia cv. Lilliput, Sunflower cv. Elf, French Marigold cv. Orange Gate, African Marigold cv. Crush, Cockscomb cv. Bombay and Cosmos cv. Sonata Pink) were sown into module trays containing leaf mould compost. After 70% emergence of each cultivar, two experiments were conducted to control plant height. In first experiment, plants of each cultivar were treated with standard dose of widely applied PGRs (30ppm of A-Rest, 30ppm of Bonzi, 1000ppm of Cycocel) along with a control treatment. In second experiment, plants of same cultivars were kept under long day (LD) non-inductive environment for 2, 4, 6 and 8 weeks. After each time scale these plants were transferred to their SD inductive environment chamber until flowering. Findings of this study revealed that all three PGRs significantly (P<0.05) reduced plant height of Facultative SDPs as compared to control. Similarly, plants placed for a short duration (2 weeks) under LD non-inductive environment produced more or less similar results as PGRs one. However, if taller plants are preferred then this duration can be extended up to 8 weeks. The advantage of preferring non-inductive environment technique over PGRs one is that it is non-hazardous, environment friendly and less expensive.