The effects of photoperiod, pinching, and plant growth regulators on growth and flowering of Abutilon x hybridum

Abutilon x hybridum, flowering maple has the potential to become a profitable floriculture crop. However, growing guidelines need to be developed in order to produce a proportional, well-branched, and uniform-flowering pot plant. The objective of this research project was to form a foundation on which a commercial growing program could be developed.

Growing flowering maple under short-day conditions (SD) significantly reduced plant height. Plants grown under SD were nearly half as tall as those plants grown under long-day conditions (LD). Also, plants grown under SD flowered an average of 5 days earlier than those plants grown under LD. Ancymidol at 50 ppm was successful in the reducing the height of nonpinched plants.

Chemical pinching agents, including mefluidide and Atrinal, induced more lateral branch development and increased flower production of both seed-grown and cutting-grown plants. As the concentration of mefluidide and Atrinal increased, so did the number of flowers that were produced. Atrinal at 1000 ppm appeared to be the treatment of choice for producing the most aesthetic and marketable flowering maple plant.

A foliar application of GA₄₊₇ at 100 ppm was successful in elongating peduncles without producing a disproportional increase in plant height. The peduncles of both seed-grown and cutting-grown plants receiving 100 ppm GA₄₊₇ were nearly twice as long as the controls. Thus, GA could be used to improve the flower display of Abutilon.