Abstract
Potato dormancy is a major obstacle in post-harvest evaluations for the certification of seed. Objectives of this study were to evaluate the efficacy of several treatments to break dormancy and induce sprouting soon after harvest for Russet Burbank, Clearwater Russet, and Umatilla Russet. Treatments included: (a) control held at 18.3 C, (b) cold-stratification held at 4.4 C for two weeks, (c) temperature fluctuation held at 4.4 C for five days, 18.3 C for four days, then 4.4 C for five days, (d) a dip in 20 ppm gibberellic acid (GA) solution, e, f, g) three different applications of cold aerosol smoke, and h) a combination of cold aerosol smoke followed by a dip in GA solution. Treatments were applied at three separate timings (individual trials) approximately four (October), six (November), and 10 (December) weeks after harvest and repeated over two years. Sprout development was evaluated weekly following each application. Treatments were more effective at promoting sprouting at later application timings. Cold-stratification and temperature fluctuations did not significantly increase the odds or probability of sprout development for any application timing or cultivar compared to the control. Smoke and GA based treatments increased the odds of having greater sprout development compared to the control at each timing. The combination of smoke and GA significantly encouraged sprout development and sprout length compared to the control. This study provided efficacy data for several dormancy breaking techniques that could be used for seed certification post-harvest testing, greenhouse production, or multiple cropping within a year.