Improvement Yield and Quality of Dahlia Flowers by Exogenous Application of Gibberellic Acid and Salicylic Acid under Sandy soil Conditions

Abstract

Dahlia is one of the popular cut flowers in the world which characterized by the rich variety and attractive flower colors. Hence, in a field study 100, 200, 300mgL−1 gibberellic acid (GA3) and salicylic acid (SA) were used during two successive seasons 2015 and 2016 to determine the possible role of each growth regulator in improving marketable quality, increasing yield and vase life of dahlia. Results indicated that the tallest plants (118.43cm) were those sprayed with GA3 at 200mgL-1. Additionally, it showed that foliar application of GA3 or SA at 200mgL−1 significantly increased the number of branches plant-1, fresh and dry weight plant-1, leaf numbers, leaf area plant-1, flower numbers, flower quality and vase life as well as tuber length, and numbers plant-1. The most rapid flowering (39.57 days after planting) occurred when plants were sprayed with GA3 at 200mgL1. Concomitant to the enhancement in the vegetable and flowering attributes, an increscent in the anthocyanin content and total soluble solids was observed in the petals by increasing GA3 and SA concentrations up to 200mgL−1. Additionally, a significant increment in the total chlorophyll content was recorded with GA3 and SA treatments. In conclusion, the vegetative and flowering characters of dahlia could be improved by application of either GA3 or SA.