Influence of Paclobutrazol on Shoot Growth and Flowering in a High-density Pecan Orchard

Paclobutrazol (PBZ) was applied to 6-year-old pecan ( Carya illinoinensis ) trees as a basal trunk drench (0, 30, 90, and 150 mg·cm −2 trunk cross-sectional area) in Dec. 2012. Terminal shoot growth was retarded for 1 year after a single application of PBZ. The total number of current season shoots showed a significant increase with 30- and 90-mg·cm −2 PBZ treatments. After PBZ application at 30, 60, and 90 mg·cm −2 , the percentage of very short shoots (30 cm) was decreased to 7.4%, 5.1%, and 7.6%, respectively, after PBZ application, compared with 18.7% with control. Shoots varying from 5 to 30 cm in length accounted for at least 63.3% of all pistillate inflorescences the following spring.