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ABSTRACTping system, the crop species, and the cultivar. Organic farmers require cultivars that can be multiplied and culture assigns an ethical value to this integrity, and encourages propagation, breeding, and production systems that protect or enhance it.

Average potato yields in Dutch organic farming systems vary from 15 to 29 Mg/ha and are limited by low input of nitrogen and severe late blight attacks caused by the oomycete Phytophthora infestans. Under Dutch late blight regulations it is mandatory to kill the haulm at 7% infestation. The late blight attacks have been so early in the organic potato production of the past few years that its acreage is now gradually decreasing whereas consumer demand is increasing. Agronomic control strategies have limited success. First priority lies in breeding for highly resistant varieties to safeguard organic potato production in the Netherlands. Cisgenesis, however, is not an option for the organic sector. Although the product of cisgenesis does not contain genes from non-crossable species it is a result of a genetic engineering process which is excluded from use in organic agriculture. As the principles and standards of organic agriculture are process-based, cisgenesis does not comply with the norms and standards of organic agriculture. The arguments of the organic sector go well beyond the alleged risks of the gene technology and relate to the technology itself. Breeding at DNA-level, instead of at whole-plant level, violates the integrity of life as described in the concept of naturalness. The Dutch organic sector is now aiming at increasing the traditional breeding activities including the participation of farmer-breeders in close cooperation with the formal breeding companies. Additional selection methods need to be developed to include required traits other than late blight resistance, such as nutrient efficiency. Recently

Thrips tabaci is a major problem in the cultivation of cabbage for storage, as this pest causes symptoms that necessitate the removal of aVected leaves from the product. Between cabbage varieties large diVerences in susceptibility occur. This study aimed to identify plant traits associated with these diVerences, in Weld experiments with natural infestation in 2005 and 2006. One factor aVecting the amount of thrips damage was the timing of the development of the head. In an experiment with diVerent planting dates especially the early maturing, more susceptible varieties were shown to beneWt from later planting. In comparisons of multiple varieties in both years, regression studies showed that more advanced plant development in August and early September increased thrips damage at the Wnal harvest. However, no single plant trait explained more than 25% (2005, Brix) or 48% (2006, compactness) of the variation in thrips damage. Optimal regression models, explaining up to 75% of the variation in thrips damage included Brix and leaf surface wax late in the season, as well as an indicator of plant development earlier in the season, and in 2005 also leaf thickness. The possible role of these plant traits in relation to thrips is discussed.

In organic agriculture the use of genetically modified organisms (GMOs) is banned. Recently, two novel breeding techniques have been developed, i.e., cisgenesis and reverse breeding, both of which are based on gene technology but should raise less moral concerns from the public. Whether the products of these breeding processes are classified as GMOs depends on the interpretation of the relevant EU regulations. In cisgenic plants, the genes introduced through genetic modification are from a crossable donor plant so that the source of the genes is considered to be of the same nature. In reverse breeding, the recombinant genes, essential to the breeding process, are no longer present in the product resulting from the entire breeding process, and thus the product as such is not transgenic. Should varieties obtained through cisgenesis or reverse breeding be allowed in organic agriculture? The answer to this question depends on whether the product or the process of breeding is taken into account. Assessment based on the product implies a choice of an ethical approach that only considers the extrinsic consequences of human action by making a risk-benefit analysis. It neglects so-called intrinsic, ethical arguments related to the applied technology (the process) itself. The organic movement uses the intrinsic argument of 'unnaturalness' against genetic engineering. We therefore conclude that products of cisgenesis and reverse breeding should be subject to the current GM0-regulations in organic agriculture and should thus be banned from organic agriculture.