Effects of Nitrogen Fertilization and Water Replacement Level on the Production of Gladiolus Corms in a Protected Environment

The objective of this study was to evaluate the effects of water replacement levels (50, 75, 100, 125 and 150%; for the 100% level, the water replacement volume was at field capacity) and nitrogen doses (0, 30, 60, 90, and 120 mg dm-3) on the production of gladiolus (Gladiolus grandiflorus L.) corms, White Friendship variety. The project was developed in a protected environment using a randomized complete block design witha 5x5 factorial scheme (water replacement levels × nitrogen doses). The evaluated variables werecorm diameter and weight and cormel number and weight. The data were assed using analysis of variance F-test at 5% probability and a regression analysis using the Sisvar statistical program. There was no nitrogen fertilization effect on the analyzed variables. The water replacement levels had a significant effect. For corm weight, the water replacement level that led to the highest weight was 128.96%. The weight and number of cormels were fit using an increasing linear regression model. According to Brazilian commercial corm standards, quality corms with diameters that suggest good potential for floral stem production were observed starting at the 50% water replacement level.