RESPONSE OF Stevia rebaudiana Bertoni TO FOLIAR APPLICATION OF GA3 AND IBA. 1. Morphological and yield traits

Abstract

The field experiment was carried out during the two successive seasons 2007/08 and 2008/09 aiming to investigate all the factors that may affect the morphological traits of stevia plants; Stevia rebaudiana Bertoni. Two different types of growth regulators; GA 3 and IBA with three concentrations 0, 250 and 500 ppm, in addition to two sprays. The most remarkable results could be summarized, with regard to the adopted concentrations or number of sprays, GA 3 treatments generally caused elevation in the averages of plant height and the number of branches per plant as compared with IBA treatments. Plants received two sprays regardless of the type of the used growth regulators (GR's) or the used concentration were the tallest and more branched. In addition, a positive relationship could be established between averages of plant height and the number of branches per plant and the adopted concentration. The interaction between the three studied factors proved that the double spray treatment by GA 3 with 500 ppm showed a remarkable elevation in the mean values of all studied morphological and yield characters.