The Effect of Application of Gibberellic Acid on Vegetative and Apical Development of nutans and erectum Barleys

Summary A survey was made of the effects of applying 7 μg of GA3 to the first leaf of 39 spring cultivars of barley. The rate of apical development and effects on lengths of the leaf laminas and sheaths were measured and the study confirmed that considerable variation exists between both cultivars and tissues in their response to GA3 treatment which is independent of the 2 or 6 row and erectum or nutans characters. Both vegetative and apical growth were affected by GA3 treatment and no cultivar was found to be entirely insensitive in either respect. The implications of these results for understanding of the role of gibberellins in spike development are discussed.