A Theory of Blossom Thinning to Consider Maximum Annual Flower Bud Numbers on

Tree fruit growers use chemical and mechanical thinning techniques in an attempt to maintain regular annualflower production and maximum repeatable yields of varieties susceptible to biennial bearing. If the percentage of floral buds an apple tree could produce without causing yield depression in subsequent years was known, it would be possible to better manage crop-thinning regimes. This study proposes that thinning is apartialtransferofpotentialflowerbudsfromoneyeartothenextyearandestimatesthe maximum repeatable sequence of flower buds without biennial bearing. The conceptual framework is tested on a 50-year simulation with 0% to 100% transfer of thinned flower buds. Results indicate that the maximum repeatable sequence of flower buds rises sharply when the final years of the orchard approach and declines when the percent transfer of thinned buds is near 0%.