Crop growth and tuber yield of "early" potato crop under organic and conventional farming

Intensive applications of farming inputs are generally associated to potato cultivation in several Mediterranean countries for "early" potato production. Recently, the enhanced interest for environmentally sustainable production systems has led to a major expansion in the organic farming sector. With the aim to identify cultivars which can be suitable for organically early potatoes crop in Mediterranean environment, a three-season experiment was carried out in Sicily (Southern Italy) to study the effects of comparison between organic and conventional cultivation systems on crop growth and tuber yield on five genotypes. These included three cultivars (Ditta for organic Arinda and Marabel for conventional cultivation systems) and two new genotypes, Bionica (Dutch cultivar specifically targeted for organic farming) and an Italian breeding clone ISCI 4F88 suitable for organic cultivation. The response of the 'early' crop potato to organic farming was genotype- and season-dependent. The organic cultivation system was less productive than the conventional one across the 3-season (-5% season I, -50% season II and -25% season III), due to a less availability of N and to appearance time and severity level of late blight infection. Moreover ISCI 4F88 deserve specific consideration due to its higher stability traits than the cultivar Ditta under organic cultivation system during the three seasons. Our results indicate that organic cultivation of 'early' potatoes can deliver acceptable agronomic performances. Further studies are still needed to assess the behavior of other genotypes adapted to "early" potato cropping as selection of appropriate cultivars is one of the key aspects to optimize this environmentally friendly production system. (C) 2013 Elsevier B.V. All rights reserved.