Influence of Paclobutrazol Plant Growth Regulator on Strawberry Plant Growth, Fruiting, and Runner Suppression

Abstract

Paclobutrazol (ICI PP333), an inhibitor of gibberellin biosynthesis, suppressed early season number of berries but did not affect seasonal yield of field grown strawberry plants. Plant growth was greatly suppressed at all application rates. Petioles, peduncles, and pedicels were shortened with leaves and fruit tightly appressed to the crown. Green leaf color was intensified in all paclobutrazol treatments, but fruit color was not appreciably influenced. Runner suppression was obtained in mid-July field applications, but runners were not inhibited by August application. In the greenhouse, PP333 applied directly to the soil of potted plants was more effective than foliar applications in suppressing crown, leaf, and root growth. The degree of suppression generally was related to increasing the concentration of the chemical.