PLANT GROWTH REGULATORS ALTER FRUIT SET AND YIELD IN CRANBERRY (VACCINIUM MACROCARPON AIT.)

Proprietary plant growth regulators (PGR) of Abbott Laboratories, Inc., North Chicago, IL, were applied to ‘Searles’ cranberries in 1986 and 1987. In 1986 six compounds including kinetin plus gibberellin (6-benzyladenine + GA₄₊₇ and undesignated compounds ABG 3073 and ABG 3068 were applied at 100 ppm concentration at 50% bloom, 100% bloom and 7 days postbloom stages.
ABG 3028C and ABG3035 enhanced fruit set to 51–53% compared to 26% for the untreated control.
Mean berry weight was reduced but total yield was not affected.
Berry seed counts verified parthenocarpic fruit development in response to PGR treatment.
Most PGR treatments resulted in extensive elongation of vines (upright growth) and inhibited terminal fruit bud development.
The PGR 6-benzyladenine (6-BA) suppressed fruit set; 6-BA+GA₄₊₇ did not influence fruit set but reduced berry weight and yield.
In 1987, PGR treatments were reduced to 25 ppm and 75 ppm concentrations.
The lower concentration in general was as effective as the higher in increasing fruit set with all compounds tested.
Fruit set was increased to 34%–57% compared to 22% in the control.
ABG 3028C, ABG 3073 and ABG 3077 increased yield.
ABG 3077, a new compound (undesignated) increased fruit set by 71% and yield by 60% compared to the control.
Berry size was not altered, undesirable elongation of vines (uprights) did not occur and suppression of terminal bud set was not apparent.

IV International Symposium on Vaccinium Culture

Elden J. Stang, Brian A. Birrenkott

https://doi.org/10.17660/ActaHortic.1989.241.47