The effects of gibberellic acid upon growth habit and heading in late-flowering red clover (Trifolium pratense L.)

Publisher Website
Google Scholar
Abstract
The response of S. 123 extra-late-flowering red clover in the year of sowing to three sprayings of gibberellic acid (GA) given at 28-day intervals is described. Plants in both soil and vermiculite cultures were used.1. The first effects, noticeable in the basal rosette, were an increase in petiole length and a parallel increase in leaf area.2. Fewer stems were formed on the treated plants but their thickness and the number and length of the internodes were increased.3. Secondary branching was not significantly increased but the GA-treated plants produced a large number of tertiary branches from axillary buds on the secondary branches. Tertiary branching was not frequent in the control plants.4. Cauline leaves showed an increased length/breadth ratio at each node with treatment, elongation tending to be most marked at those nodes where leaf formation coincided with GA sprayings. Leaf thickness was also increased by GA treatment.5. Treated plants produced nearly 80% more heads, and flowering after GA treatment was up to 14 days earlier than the control.