Effect of Some Growth Regulators and the Dates of their Addition on the Growth and Yield of Stevia Plants (Stevia Rebaudiana Bertoni)

Abstract

A field experiment was conducted that included two factors: the first factor; Growth regulators: gibberellin (GA3), salicylic acid (SA) and benzyl adenine (BA) at a concentration of 100 mg / liter of each with the comparison. the second factor; processing dates; It is 3 appointments, the first - spraying 30 days before the first cut. The second - spraying 30 days before the second cut. And the third - spraying 30 days before the first cut and before the second cut. The results showed in the characteristics of vegetative growth the significant effect of growth regulators, especially the significant superiority of GA, SA and BA in the characteristics of vegetative growth, such as the height of the plant, which was characterized by gibberellins (113.5 cm) compared to 76.8 cm in comparison plants, as well as the superiority of the mentioned process in the number of leaves that were characterized by all The organizations used SA, BA and GA, which gave a large number of sweet leaves, reached an average of 469.0, 457.5 and 443.6 leaves/plant, respectively. These organizations also excelled in leaf area and in the biological yield, which was significantly superior using the above mentioned organizations, reaching 73.57 and 65.58 and 60.41 g/plant respectively. At the same time, the dates of adding growth regulators showed that the third and first dates often exceeded in most of the studied traits. In the yield traits, the results showed the role of encouraging growth regulators for all floral growth traits, especially the number of flowers, which reached (1262.44, 1132.67 and 922.78 flowers/plant) when treated with GA, SA and BA, respectively, while it reached 834.78 flowers/plant in the control plants. Also, these organizations outperformed in the trait of 1000-seed weight and in seed yield per (one) square meter, where the seed yield reached (15.59, .13.58 and 12.20 g/m2), respectively, in the aforementioned organizations, compared to 8.66 g/m2 in the untreated comparison plants. The results showed The third date was significantly superior in most of the studied traits.