A field experiment was conducted to investigate the effect of plant compost (0, 7.5, 10.0 and 12.5 ton/fed) and salicylic and/or ascorbic acids (each at 0, 100 or 200 ppm) on corm production and chemical constituents of Gladiolus grandiflorus cv. White Prosperity. The obtained results indicated that corm diameter, number of cormels/plant, dry weight of corm and cormels, as well as, chemical constituents including chlorophyll a, b, carotenoids and percentages of N, P and K in the corms were gradually increased by increasing the level of compost. Significant differences were detected among four used
treatments. So, the high level of compost resulted the highest values. All six treatments of salicylic acid and/or ascorbic acid significantly increased corm and cormels production and their content of chemical constituents in comparison of the control plants. The treatments of salicylic acid (100 ppm) plus ascorbic acid (100 ppm) followed by ascorbic acid (200 ppm), then salicylic acid (200 ppm) were more effective than other treatments for corm and cormels production, as well
as, the percentage of nitrogen and potassium without significant differences were detected between the first and second treatments in most cases. While the treatments of salicylic plus ascorbic acids, each at 100 ppm followed by salicylic acid at 200 ppm were more effective for the pigments content (mg/g f.w.) and phosphorus percentage without significant differences between them. The interaction between compost, salicylic acid and/or ascorbic acid was significant for all previous characters, except K %. The highest values of corm and cormels production were achieved by 12.5 ton/fed
compost treatment in combination with salicylic acid (100 ppm) + ascorbic acid (100 ppm) or ascorbic acid (200 ppm), while the interaction treatments of compost (12.5 ton/fed) × salicylic plus ascorbic acids, each at 100 ppm or compost (12.5 ton/fed) × salicylic acid at 200 ppm recorded the highest contents of pigments and elements of N and P.