Grain yield responses to applied gibberellin in normal-height and semi-dwarf wheats

Abstract

Yield responses to applied gibberellic acid (GA3) were measured in four normal-height (gibberellin-sensitive) and three semi-dwarf (gibberellin-insensitive) wheats (Triticum aestivum L. em Thell.). Application was made to the head and leaves of the primary tiller separately at heading and jointly at heading and anthesis. The general effect of applied GA3was to decrease grain yield per head, mainly by decreasing the grain number. Increased yield was, however, obtained with two normal-height wheats due to increased grain number, when GA3was applied to the leaves alone at heading and jointly to the leaves and head at anthesis. There was a general decrease in the mean grain size of semi-dwarf wheats with all applications, while the response of the normal-height wheats ranged from little change to a significant increase. Thus distinct group differences between normal-height and semidwarf wheats in yield response were not apparent.