Breeding 17 July 2018

Growing demand
for organic potatoes
encourages breeding

Organic potatoes are on the rise, especially now that the large supermarkets have embraced the product. But what to do against the dreaded disease Phytophthora? A conversation with professor of organic plant breeding, Edith Lammerts van Bueren.

‘The market share of organic products is growing rapidly. In the Dutch supermarkets, turnover is increasing by 10 percent annually, but the potato is lagging behind’, says Edith Lammerts van Bueren. She has been working on the improvement of organic vegetable and potato cultivation for decades.

Potato fields cannot do without crop protection. Traditional growers spray against Phytophthora, or late blight, at least once a week. Organic farmers only have a small number of varieties at their disposal that do not offer complete protection against the devastating disease.

Green breeding

According to the professor, at least 20% of the organic farmers stopped growing potato between 2000 and 2007. ‘They could no longer cope with the intense waves of this disease.’ Lammerts van Bueren then initiated a scientific research programme into green potato breeding with support of the Dutch Ministry of Agriculture and a number of breeding companies. ‘I felt that as a leading arable farming country, the Netherlands could not afford to drop organic potato cultivation.’ HZPC is also involved in the Bioimpuls project.

There are now a handful of varieties available that are resistant to late blight. However, the ‘technical’ restriction of these varieties is that they contain only one resistance gene. Breeder Peter Vos of HZPC is concerned. ‘Phytophthora is so ingenious that the disease sometimes seizes the opportunity to bypass single genetic protection. We all have to be careful not to place the current resistance genes at risk that way”.

Edith Lammerts van Bueren agrees with him. ‘We also prefer to work with stacked genes, but that takes longer and the organic sector can no longer wait for resistant varieties. It was a deliberate choice of the sector to start with single genes. ‘She also points out that although the current number of resistant varieties is low, they still contain five different resistance genes. ‘That is already a satisfactory result for the time being.’

An extra lock on the door

HZPC is developing varieties that include at least two genetic resistances. ‘This offers more effective protection against late blight. You then have an extra lock on the door,’ explains breeder Peter Vos. According to HZPC, this is the best way to actually achieve sustainable resistance.’

‘Everyone wants farmers to spray less. In future, we aim to provide the entire potato sector, organic and conventional, with resistant varieties that are multi-resistant. Vos admits that this will not happen overnight. ‘Genetic progress takes time.’

HZPC currently has one resistant variety, Zarina, which is being introduced in East Africa. ‘We also have several varieties in development, one of which has the potential to be introduced onto the Dutch market very soon.’

Moral duty

The professor nevertheless shares HZPC's concern about the vulnerability of the resistant varieties. Growers have to check their crop effectively. As soon as the disease breaks through the resistance somewhere, they immediately have to act and spray or burn the crop. ‘In our programme we are on top of that. It is a moral obligation of the growers to be careful with this heritage’.

Lammerts van Bueren expects the breeding for resistant varieties to make larger steps in the coming years, also with multi-resistance. This is badly needed now that large supermarkets like Albert Heijn, Jumbo, and Aldi have signed the covenant ‘Robust potato varieties’. By 2020 all potato varieties in the organic range must be resistant to Phytophthora.

The professor has confidence in the progress of the breeding research. ‘We are constantly expanding and gaining practical experience with demo fields in different areas. The entire potato sector is aware of the importance.’



Edith Lammerts van Bueren (1952) studied plant breeding and horticultural plant production. In 1978 she started working as a teacher at the Warmonderhof, the technical college for biodynamic agriculture.

In 1985 she moved to the Louis Bolk Institute for sustainable agriculture, nutrition and health. Since 2005, Lammerts van Bueren has also worked as an extraordinary professor of organic plant breeding at Wageningen University.

She is the initiator and driving force behind the green breeding programme Bioimpuls and together with Bionext co-created the covenant 'Robust potato varieties'.

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