Prof. Ahmed Said Mohamed Youssef :: Publications:

A two- year field experiment was carried out during two successive seasons of 2005 & 2006 to investigate the effect of GA3 treatments (0.0, 100, 200 and 300 ppm) applied by three methods i.e., tubers soaking (so) before planting, foliage spraying (sp) and tubers soaking + foliage spraying (so+sp), kristalon fertilizer (Foliar fertilizer containing macro and micro-elements) which applied at the rates of (0.0, 2, 4 and 6 g/L water) and their combinations on the growth, flowering and chemical composition of Dahlia pinnata plants (summer flowering type). Conclusively, all tested treatments of GA3, kristalon fertilizer and their combinations succeeded in improving the studied vegetative and flowering traits as well as leaf chemical composition determinations. However, the tallest plants were produced by using tubers soaking supplemented with foliage spraying with GA3 at 300 ppm (so+sp) and spraying the foliage with kristalon fertilizer at 6 g/L .Besides, the highest number of branches and fresh weight of foliage/plant were registered by using 200 ppm GA3 tubers soaking and spraying the foliage with kristalon fertilizer at 4 g/L Moreover, the thickest branches diameter was obtained by soaking the tubers in GA3 at 100 ppm provided with spraying the foliage with kristalon fertilizer at 6 g/L. In addition, the least number of days to start flowering was achieved by using the combined treatment of GA3 at 300 ppm (so+sp) and spraying the foliage with kristalon at 2 g/L. Furthermore, spraying the foliage with GA3 at 300 ppm and applying kristalon fertilizer at 6 g/L produced the tallest flower pedicel, while spraying the foliage with GA3 at 100 ppm and kristalon fertilizer at 6 g/L gave the thickest flower pedicel and flower head diameter. Moreover, the highest number of flowers, heaviest fresh weight of flower/plant, the longest duration of flower on plant and vase life were obtained by using GA3 at 200 ppm (so+sp) and spraying the foliage with kristalon fertilizer at 6 g/L Also, the previously mentioned treatment produced the highest number and heaviest fresh weight of tuberous-root /plant. Thereupon, it is preferable to use the combined treatment between GA3 at 200 ppm (so+sp) and kristalon fertilizer at 6g/L to achieve the best growth and flowering traits for Dahlia pinnata plants.