Effect of abscisic and gibberellic acid on grain set in wheat

When abscisic acid was applied to wheat ears at or just before anthesis, it prevented grain set in the third floret of each spikelet but not in the lower florets. It had no effect on semi-dwarf cultivars in pot experiments, but there was a small response in a field experiment. Gibberellic acid inhibited anthesis in all florets of all cultivars.