Effect of Glycine, Methionine and Tryptophan on the Vegetative Growth, Flowering and Corms Production of Gladiolus Plant

The present study was carried out during the year of 2015 at two different locations i.e. nurseries. The first location was at The Department of Floriculture, Ornamental Horticulture and Garden Design, Faculty of Agriculture, University of Alexandria at Shatby and the second location was at Montazah Research Branch, Horticulture Institute, Ministry of Agriculture, Alexandria Egypt, to investigate the effects of different concentrations of glycine (zero, 75, 225 and 450 ppm), methionine (zero, 150, 300 and 600 ppm) and tryptophan (zero, 300 , 600 and 900 ppm) with two application methods (pre-soaking the corms for 24 h before planting, or foliar spraying three times at stages of formation of 2,4, and 6 leaves) on the vegetative growth, flowering characteristics ,corms production and some chemical analysis of Gladiolus grandiflours cv. "Rose Supreme " plants.  The corms of the used cultivars were planted on January 27, 2015 in 30 cm plastic pots filled with a mixture of sand and peat moss at the ratio of 4:1 by volume, respectively. All the normal culture practices of growing Gladiolus corms were applied as usual manner. The experiment layout was designed to provide complete randomized blocks containing four replicates, each replicate had 24 treatments and three corms were used for each treatment in each replicate (plot). Results revealed that using the lowest concentration from any of the used amino acids (glycine at 75 ppm or methionine at 150 ppm or tryptophan at 300 ppm) regardless of the used application method (presoaking or foliar spraying) gave the highest significant increase in most of the studied parameters of gladiolus plant (vegetative growth, flower characteristics, corms and cormels production and some of the chemical analysis) compared with the control treatment. While, leaves number per plant and the time taken by flower buds to show their color did not significantly affect with the used amino acids concentrations and their application methods,  compared with the control treatment. Besides, using the highest concentration from any of the used amino acids (glycine at 450 ppm, or methionine at 600 ppm, or tryptophan at 900 ppm) gave the tallest spikes, compared with the other concentrations. The largest corms fresh weight was obtained by using glycine at 75 ppm, compared with the other treatments. Using methionine at 150 ppm or 300 ppm, regardless of the used application method, gave the highest content of nitrogen
and total carbohydrates content of the produced corms, respectively, compared with the other treatments. From the previous results, it can be generally recommended treating Gladiolus grandiflorus cv. "Rose Supreme" with presoaking the corms for 24 h before planting in tryptophan solution at 300 ppm or with 100 ppm three times as foliar spraying at formation of two, four, and six leaves to obtain the maximum improvement of the vegetative growth, flowering characteristics, corms and cormels production.