RESPONSE OF GLADIOLUS PLANTS TO HUMIC ACID, BORIC ACID AND POTASSIUM SILICATE

A field experiment was conducted during two successive seasons, 2016/17 and 2017/18 to study the effect of humic acid (HA), boric acid (BA) and potassium silicate (PSi), as well their interaction on vegetative growth, flowering aspects, corm production and photosynthetic pigments of Gladiolus grandiflorus cv. Eurovision plants. The main plots included HA at 0, 0.25 and 0.50 g/l, while the sub-plots included BA at 25 and 50 mg/l, PSi at 50 and 100 mg/l and B/Si at low and high levels of both substances. Humic acid or BA and/or PSi augmented different studied traits, however the interaction treatment between the high level of HA plus the dual treatment of BA/PSi resulted in the best vegetative growth characters, flowering aspects and corm production. Meanwhile, flowering date was delayed and number of florets/spike was not affected due to this treatment. It is recommended to supply Gladiolus grandiflorus cv. Eurovision plants with HA at 0.50 g/l in combination with BA at 50 mg/l and PSi 100 mg/1 in order to obtain the best flowering aspects and the maximum corm and cormels production.