GM maize test results announced

3 October 2002

The Ministry of Agriculture and Forestry (MAF) and ERMA New Zealand today announced that they had completed their investigations into the genetically modified (GM) maize crops harvested earlier this year at Pukekohe and Gisborne.

In summary, their findings were that: 

  • hybrid maize containing very small concentrations of GM varieties was grown at Gisborne and Pukekohe;
  • the most likely source of this material was from very small concentrations of GM seed in the imported parent seeds;
  • it is most unlikely that any GM seed in the hybrid maize harvested was due to cross-pollination from adjoining crops during growth in New Zealand;
  • it is most unlikely that the affected crops pollinated nearby fields containing maize or sweet corn crops.

The concentrations of GM seed in the crops was very small - less than 0.05% or one in 2,000 seeds in the Gisborne samples and probably even smaller than that in the Pukekohe samples. Of the approximately 1.8 million maize plants grown in these fields, probably fewer than 800 contained GM material.

No GM seed was detected in the male parent seed grown at Gisborne, meaning that there was no risk of GM cross-pollination from fields on which this seed was grown. The Gisborne female parent seed contained the GM variety "YieldGard" and probably Bt176 as well. "YieldGard" and Bt176 are GM maize varieties resistant to corn-borer insects. Although the Gisborne female lines contained very small concentrations of GM seed, the removal of their tassels - normal practice for hybrid seed production - meant they were unable to produce pollen.

At Pukekohe, GM seed was detected in both male and female parent seed. The female seed contained "LibertyLink". The variety in the male seed was not identified but it is suspected to be a "YieldGard" variety. "LibertyLink" is a variety resistant to the herbicide "Liberty".

Although both male and female parents at Pukekohe contained a minute concentration of GM seed, the fields in which they were grown were well separated from other fields of maize or sweet corn in the area. All but one of these nearby crops also flowered at a time when they would not have been receptive to pollen from the affected maize.

It is most likely that the GM seeds in the imported parent lines were not detected because of the minute concentrations present. This is evidenced by GM seed being detected in Pukekohe hybrid seed samples taken by Pacific Seeds but not being detected in the samples taken by MAF. The likelihood of detecting GM seed in a line using a sample of 3,200 seeds at a GM seed concentration of 0.04% is 71%.

MAF and ERMA New Zealand have agreed management protocols with Pacific Seeds for the fields at Gisborne and Pukekohe where these crops were grown. These protocols include regular inspections for maize plants that germinate from residual seeds and the destruction of these plants by measures such as cultivation or spraying with a herbicide. MAF will inspect each field to verify it is clear of volunteers before that field is available for normal use and freed from continued monitoring.

MAF and ERMA New Zealand note that Pacific Seeds has co-operated fully throughout this investigation and have agreed to manage the sites as requested.

Media contact:

Brett Sangster, MAF Director Corporate Communications

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