Gibberellin A4/7 enhanced flowering in Pinuscaribaea var. hondurensis

Abstract

Gibberellin A4/7 was applied to field-grown grafts of sexually mature poor and good flowering clones of Pinuscaribaea Morelet var. hondurensis. Barr. & Golf. Continuous applications of gibberellin A4/7 over a 6-week period significantly enhanced seed-cone production in poor flowering clones but had no effect on good flowering clones. Poor flowering clones also showed slight decreases in pollen-cone production with gibberellin A4/7, while clones that normally flowered well did not. Gibberellin A4/7 increased final shoot lengths in the lower (male) and upper (female) crown region of both poor and good flowering clones. A series of timed gibberellin A4/7 applications suggested that a single treatment near the onset of reproductive bud development may be used to enhance seed-cone production.