This study was undertaken during two successive seasons (2012/2013 & 2013/2014) to evaluate the effect of GA3 foliar sprays at(0.0, 50, 100 and 150 ppm.) and chemical fertilization NPK at aratio of 1:1:2 namely (0.0, 2, 4 and 6 g / plant) as well as their combination on the growth, flowering, corm production and chemical composition of Gladiolus grandiflorus cv. White Prosperity plant. Obtained results showed that all tested GA3 concentrations and NPK chemical fertilizers treatments as well as their combination increased vegetative growth parameters i.e., leaf length, leaf area, number and fresh weight of leaves / plant as compared with control in the two seasons. Moreover, the longest spike and flowering portion as well as the highest number of florets / spike were scored by GA3 at 150 ppm combined with chemical fertilizer at 6 g / plant in the two seasons. The thickest spike and the heaviest fresh spike were recorded by GA3 at 100 ppm enriched with chemical fertilizer at 6 g / plant, while the thickest lower floret was gained by the combined treatment between GA3 at 50 ppm and chemical fertilizer at 6 g / plant in the two seasons. Moreover, GA3 at 50 ppm supported with chemical fertilizer at 6 g / plant produced the thickest corm and the heaviest fresh corm in the two seasons. Whereas, the highest number of cormels and the heaviest fresh cormels / plant were recorded by 100 ppm GA3-sprayed plants , fertilized with chemical fertilizer at 6 g / plant in the two seasons. Also, all tested combinations between GA3 and NPK chemical fertilizer significantly increased leaf N, P, K and total carbohydrates content, particularly using the combinations between GA3 at 150 or 100 ppm and NPK chemical fertilizer at 4 or 6 g/plant in both seasons. Conclusively, treating Gladiolus grandiflorus cv. White Prosperity plants with GA3 at 150 or 100 ppm combined with NPK chemical fertilizer at 4 or 6 g/plant showed the best vegetative, corm production and flowering characteristics with high quality |
