Pests and diseases have been a scourge to agriculture since agriculture began, and they still destroy about 20 percent of crops planted globally, even though farmers spray 2.7 million tons of insecticides and fungicides on fields globally each year, according to the International Potato Center (CIP).
Those agrochemicals constitute a significant expense and risk to human and environmental health, but the good news is breeding approaches to develop disease-resistant varieties of staple crops are progressing in leaps and bounds. This is particularly the case with biotechnology, yet consumer fears are holding back the development or release of many biotech varieties, leaving the field clear for devastating outbreaks of crop diseases such as potato late blight.
A ubiquitous, airborne disease that destroyed potato crops in Ireland and resulted in a famine that caused one million deaths in the 19th century, late blight still affects most of the 18 million hectares used to grow potato crops today. While fungicide spraying can reduce the losses it causes, not all farmers have access to or can afford that agrochemical, especially small-scale growers in developing countries, where late blight costs farmers an estimated USD 2.75 billion annually in production loss and fungicides.
Breeding disease resistant potato varieties
Breeders have successfully developed high-yielding potato varieties well-adapted to a wide range of countries, but resistance to late blight has been a challenge. While some of the potato’s wild relatives are highly resistant, getting the genes responsible for that resistance from wild potatoes into commercially viable ones has resulted in potatoes with bitterness or other characteristics people don’t like. This requires a long and tedious process of backcrossing to weed out undesirable “wild” traits.
“It could take multiple decades to produce a variety that has the wild plants’ disease resistance and the characteristics of a commercially popular potato,” explains Marc Ghislain, Principal Scientist, Biotechnology at the International Potato Center (CIP) and a co-author of the study. “
Ghislain explains that biotechnology has enabled breeders to transfer resistance genes from wild potato species into established varieties without changing any of their other characteristics. “Farmers who grow those potatoes have little risk of crop loss or need for fungicides. They are also likely to quickly adopt them because they know there is market demand for them,” he says. “To take those varieties to scale, however, we need consumer support.”
While food safety agencies agree that crop varieties developed using gene technology in plant breeding are as safe for human consumption as those bred conventionally, genetically modified (GM) food crops continue to evoke strong consumer reactions – mostly negative – particularly in Europe.
Field trials with a late-blight-resistant transgenic potato in Sweden
Ongoing field trials in southern Sweden presented an opportunity for researchers at the Swedish University of Agricultural Sciences to let a group of consumers see one of those crops for themselves. They placed an advert on social media inviting people to join a visit to a potato field trial, making no mention of the crops they were going to see being transgenic. The 28 participants who attended that field day completed a questionnaire before and after the visit to capture changes in attitudes and willingness to purchase.
The trials were of a late-blight-resistant transgenic potato developed from the King Edward variety – a 100-year-old variety that is still very important in Sweden – into which three genes from two potato wild relatives had been introduced. The results of three years of trials showed that this transgenic version of King Edward was completely late blight resistant.
“We could reduce the use of agricultural fungicides in Sweden by several percent just by using this new resistant potato,” says Erik Andreasson, co-author and Professor in Plant Protection at the Swedish University of Agricultural Sciences.
“While the transgenic potato had shown good results over three seasons in terms of resistance, reduced costs, and the time it would take to get the improved variety into farmers’ fields, we know from previous studies that just communicating facts is not enough to gain consumer acceptance; you need to address the reasons behind their concerns,” says Marc Ghislain.
Feedback from participants in field visit
Feedback captured from the participants prior to the field visit indicated some important acceptability issues for GM crops, including that they should be perceived as being healthier than other potatoes, be the same price or cheaper, and be organically produced. Other concerns included perceptions that GM crops help big businesses more than they help farmers and consumers, and that using biotechnology in plant breeding leads to unacceptable risks.
Following the field visit, there was a positive change in risk perceptions and attitudes, indicating that personal experience and access to reliable sources of scientific information, in combination with discussion with public sector scientists, can increase the acceptance of GM products. Though the study sample was small and not representative of the wider population, it does present an approach that could be scaled up and used on other types of products.
“Farmers stand to benefit from resistant varieties improved through biotechnology, which have positive implications for human health and the environment, since fewer potentially harmful and expensive chemicals such as fungicides will need to be used,” observes Marc Ghislain.
“GM crops cannot solve all the problems farmers face on their own, but early evidence shows that if we can overcome regulatory barriers and create more positive consumer attitudes toward them, they could certainly make a significant contribution to farmer incomes, food security, and the environment,” concludes Ghislain.
Source: International Potato Center (CIP)