Risk assessment for volunteer and seedling GM potatoes in the northernmost European growing areas

Abstract

Commercial production of genetically modified (GM) potatoes (Solanum tuberosum L.) could represent a risk to conventional production if volunteer plants develop from tubers or true seeds that survive until the following growing season. We studied such risks under northernmost European conditions and monitored the effects of cultivar, tuber size and tuber depth in the soil on winter survival at MTT Agrifood Research Finland, Jokioinen (61°06′N, 23°02′E) from 2004–2007. Tubers of two non-GM cultivars, Saturna and Asterix, and two size classes, 25–30 mm and 45–50 mm, were planted at depths of 10 and 20 cm in autumn, soon after harvest. In winters 2004–2005 and 2005–2006 all tubers planted in the soil in autumn were killed by frost. In 2005–2006, the field was covered by up to 30–40 cm of snow and the minimum soil temperatures ranged between ?0.4^oC and ?0.9^oC, but only 0.0–3.5% of the tubers survived and there was no difference between cultivars, tuber sizes and planting depths. Under laboratory conditions compared with ?2.0°C and ?2.5°C, treatment at ?3.0°C for 72 h resulted in significantly lower survival rate of the tubers (8.2%). Asterix, a late maturing table potato cultivar, was more resistant to low temperatures than the processing cultivar Saturna. In general, volunteer tubers are not currently a significant risk for coexistence of GM and conventional potato production in northern Europe due to the cold winter conditions but also due to possibilities to control the sporadic volunteers from the next crop. However, we noted that seedlings initiated from true potato seed are able to produce tubers despite the short growing season. Such a risk could be reduced by accepting only non-berry-producing GM cultivars for cultivation.