Production of gladiolus submitted to gibberellic acid in a protected environment¹

Produção de gladíolo submetido a ácido giberélico em ambiente protegido

ABSTRACT

Gladiolus is an important cut flower commercialized in Brazil, and the use of gibberellic acid (GA₃) to cultivate it in a protected environment may promote the production of high quality flower spikes. This study aimed at evaluating the production of flower spikes and corms of gladiolus ('White Friendship' cultivar) submitted to high concentrations and application methods of gibberellic acid, in a protected environment. The experimental design was randomized blocks, in a 2 x 4 factorial arrangement, being two application methods (foliar spraying and corm soaking) and four concentrations (0 mg L^-1, 250 mg L^-1, 500 mg L^-1 and 1,000 mg L^-1) of gibberellic acid, with six replications and two plants per experimental unit. The following traits were evaluated: plant height, number of leaves per plant, marketable harvest point of flower spikes, number of florets per flower spike, flower panicle length, stem and floret diameter, corm perimeter, number of cormels per plant and production of corm fresh matter and leaf dry matter, flower spikes, corms and cormels. High concentrations of GA₃ are not recommended for the production of flower spikes and corms of the gladiolus 'White Friendship' cultivar. The corm soaking application method anticipates the harvest of flower spikes and produces a higher number of cormels per plant. Regardless of the application method, the concentration of 550 mg L^-1 of GA₃ increases the cormel yield of the 'White Friendship' cultivar.

KEYWORDS:
Gladiolus x grandiflorus Hort; plant growth regulator; cut flower