Apples are being genetically modified in the Netherlands to make them resistant to scab and in due course other diseases, too.
The technique being used should be more acceptable to environmentalists and consumers because the resistance genes being used come from wild apple species rather than a foreign source.
This type of genetic modification, called cisgenesis, was described by Henk Schouten of Plant Research International, based at Wageningen University, at Agrovista's spring fruit meeting, which took place on 11 February at Ashford, Kent.
He explained that with conventional breeding the production of scab-resistant varieties of good eating quality and suitability for commercial production takes as long as 50 years. This has been done using a crab apple, Malus floribunda, as the source of scab resistance. The trouble is that only one resistance gene is involved and in Holland this resistance has broken down within 10 years of the resistant variety being introduced.
The big advantages of cisgenesis, Schouten claimed, are that it is a much quicker process; several resistant genes can be used, making the breakdown of resistance unlikely; and the genes are inserted into the genomes of good-quality, established varieties, so no lengthy cross breeding is required to get commercially acceptable varieties.
Furthermore, as the production of resistant GM varieties takes only seven years, cisgenesis is potentially cheaper than the conventional approach.
"Science now knows how to isolate genes (for resistance) and introduce them into the DNA of existing varieties," said Schouten. "Once we've got the right gene in our hands it will cost about EUR500,000 (£440,000) to get it into a variety."
However, he admitted that there is a potential problem in getting a cisgenesis variety approved by the EU Commission for commercial production. This is because EU laws do not differentiate between varieties containing genes introduced from foreign and same-species sources and to get a GM variety approved is very time-consuming and costs around EUR6.8m (£6m).
"We are proposing (lobbying for) much faster and more cost-effective approval for cisgenesis varieties by getting them exempted from the GM regulations," said Schouten. "In Holland this is supported by all political parties."
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