The phenology, yield and tuber composition of ‘early’ crop potatoes: a comparison between organic and conventional cultivation systems

Potato production in several Mediterranean countries is focused on the ‘early’ crop type, and is generally associated with intensive applications of farming inputs. Here we report, for the first time, a comparison of crop performance between organic and conventional cultivation systems. Three cultivars were tested over two seasons (2007 and 2008) to record their phenology, yield and tuber chemical composition. The organic cultivation system was less productive than the conventional one across both years with respect to total yield, but in the season (2008) when late blight infection was not severe the difference was narrowed from 7% (Ditta) to 20% (MN 2-1577 S1). The Italian breeding clones (MN 1404 O5 and MN 2-1577 S1) deserve specific consideration due to their higher total yield and nutritional value (in terms of total protein and vitamin C content) under organic cultivation system than the cultivar Ditta. In addition, the organic farming produced tubers with a lower nitrate content, an important benefit in the context of human health. In conclusion, our results indicate that organic cultivation of ‘early’ potatoes can deliver acceptable agronomic and qualitative performances. However, the response of the ‘early’ crop potato to organic farming depends upon both seasonal conditions and cultivar choice. In particular, the selection of appropriate cultivars is one of the key aspects to optimize this environmentally friendly production system.