Understanding biennial bearing in apples – 2018 update

August 2018 | Jens Wünsche, University of Hohenheim, and Dario Stefanelli, Agriculture Victoria | PIPS2 project update

Why some apple cultivars fall into alternating high- and low-crop years is the focus of this PIPS2 research update. Jens Wünsche and Dario Stefanelli discuss progress in the international project investigating the physiological, metabolic and molecular basis of biennial bearing in apple.

The project brings together Australian and German researchers to better understand the processes that regulate flowering. Biennial bearing is not simply a harvest-year problem: crop load, seed development, hormonal signals and the timing of flower induction in the current season all influence whether sufficient flower buds are formed for the next crop.

For growers, the work provides scientific context for practical strategies such as early crop-load adjustment, maintaining tree balance and avoiding excessive on-crops. The update also demonstrates the value of international collaboration in translating tree physiology research into orchard-management decisions.