Runner Formation in Everbearing Strawberry as Influenced by Growth-Promoting and Inhibiting Substances

The interactive effects of gibberellic acid, abscisic acid,and benzyladenine were studied in relation to runner formationof the everbearing strawberry. In two of three cultivars studied,Ozark Beauty and Superfection, exogenous gibberellic acid stimulatedrunner formation and inhibited flowering. In the Geneva cultivar,a shy runner producer, gibberellic acid application as a foliarspray failed to induce runners. When applied in combinationwith benzyladenine, gibberellic acid greatly stimulated runnerformation Benzyladenine alone had no effect on runnering. Exogenous abscisic acid inhibited petiole length and runnerformation and had no influence on the number of inflorescencesinitiated. Response to exogenous gibberellic acid or abscisicacid varied according to the reproductive or vegetative stagethe plant exhibited at the time of treatment. Activity of endogenous gibberellin-like substances was not substantiallydifferent between flowering and non-flowering field-grown Genevaplants when sampled in long day lengths of August. Endogenousinhibitors were highly active in flowering Geneva plants andrelatively inactive in non-flowering plants The implications of these findings on hormonal balance in thestrawberry are discussed.