1 March 2004 Researcher Tackles Olive Problem

Olive trees don't like frosts any more than people do. Depending on when the tree is exposed to frost, olives suffer damage to their leaves, stems or fruit.

A new project at Lincoln University aims to find out whether spraying olives trees with a newly imported natural product before the start of the hard frost season can prevent frost damage.

It is also hoped that this new treatment will hasten flowering and fruit set before the onset of early frosts and also protect the trees throughout the cold season.

Severely frosted olive trees may take several years to recover and during that time they produce much smaller crops.

Alex Houliston, Head of Science at Christchurch Girls' High School, is taking a year out from teaching chemistry to study the frost problem in olives. He is one of 58 teachers nationwide granted a Government funded teaching fellowship that is administered by the Royal Society of New Zealand. At Lincoln University, Mr Houliston is working with Nutritional Biochemist Dr Geoff Savage of the Animal and Food Sciences Division.

"As an owner of a number of olives trees myself, I was keen to find out how to avoid frost damage. I read about this new treatment using glycine betaine and discussed it with Graham Colley of TCL Marketing Ltd who has agreed to supply it for my trial.

“There is anecdotal evidence that this product may help prevent frost damage and my trial will be the first in New Zealand for this product,” said Mr Houliston.

“Some olive growers have recently told me they are very keen to see the results of my work after being shocked last winter at the amount of damage their four to five year old trees received after a series of 13 degree frosts.”

Glycine betaine is extracted from sugar beet as a by-product of the sugar production process and appears to protect plants from metabolic inactivation during environmental stresses – water deficit, high soil salinity and extreme temperatures such as frost, by changing the osmolarity of plant cells.

“What I plan to do is obtain some reliable data on this subject by carrying out an investigation in Canterbury, a region known for its early autumn frosts.”

Mr Houliston has designed an experiment where some trees will have glycine betaine applied to them at regular intervals and some will not (as a control).

“This means that I will be able to find out if the treatment is successful at preventing frost damage in olives.”

Measurements will be taken of the total yield, the oil yield by volume and the free fatty acid content of the olives – this is a measure of the quality of the oil.

“It is important to not only know if a treatment helps avoid frost damage but also to check that the treatment does not have any unexpected effect on the quality of the oil produced,” said Mr Houliston

Janette Busch, Technical Writer, Lincoln University, Canterbury, New Zealand