Exploring rest-breaking alternatives in South Africa

The South African pome industry has been searching for chemical rest-breaking alternatives to hydrogen cyanamide.  Rest-breaking agents are crucial for ensuring a uniform bud break, which is essential for the consistent quality and yield of apple crops.

Rest-breaking agents stimulate and synchronise bud break in fruit crops that do not receive adequate winter chilling to overcome dormancy. Since most South African fruit-growing regions have mild winters, chemical rest-breaking is essential for pome-fruit production in most regions.  This is especially vital in regions with mild winters, like many parts of South West WA.

Current Research:

·       The research is evaluating several alternatives, including ammonium nitrate, potassium nitrate, vegetable oil, and biostimulants. These are being compared to the standard treatments of hydrogen cyanamide and mineral oil. 

·       Trials have been conducted over two seasons on Golden Delicious and Cripps Red apples, as well as Packham’s Triumph pears.

·       Undertaken by master’s student Jan Theron, funded by Hortgro

Preliminary Results:

·       Bud Break Performance: Hydrogen cyanamide treatments have shown the highest bud break rates so far. However, some alternative treatments have performed comparably, though generally less effectively.

·       Potential Alternatives: While alternatives like ammonium nitrate and biostimulants show promise, further research is needed to optimize their effectiveness.

·       Testing late and early applications along with combining products at different concentrations.

The South African apple industry heavily relies on hydrogen cyanamide, but with potential future restrictions, finding effective alternatives is a priority. This research is crucial for ensuring the sustainability and productivity of their apple orchards.

For more information:

Rest-breaking alternatives for apples and pears – Fresh Quarterly