Systemic Induction of Sprouting in White Potatoes by Foliar Applications of Gibberellin.

Gibberellin influences the rest period or dormancy of seeds (4), shoots (1), and other plant parts (2, 5, 9). In potato, Solanum tuberosum, a condition of physiological rest prevails from the time of tuber initiation until 6 to 12 weeks after harvest depending on varietal characteristics (3). The rest period has been markedly curtailed by immersing freshly harvested potato tubers in gibberellin (9, 10). This effect, couipled with the rapid stimulation of growth of various plants by gibberellin (6), suggested that preharvest foliar sprays of this chemical might shorten the rest period of the immature, developing tubers. Results of the experiments described herein indicate that gibberellin initiates the sprouting process of the tubers on the plant when sprouting is least likely; they suggest further (7, 12) that gibberellin moves systemically in plants. In a preliminary study (5) gibberellin applied as a foliar spray induced earlier sprouting of the subsequently harvested tubers. In a more detailed experiment, a spring crop of White Rose potatoes was grown in a split plot design with three replications of 20 plants per plot. The plants were sprayed to run-off four weeks, two weeks, or one week before harvest with solutions containinor 0. 10( 50. 100, and 500 mg/l of gibberellin.