54 I EUROPEAN SEED I EUROPEAN-SEED.COM seed, which in some market segments for example in European countries, easily amounts to 50%, while in emerging coun- tries it is not uncommon to observe 90% FSS without compensation. “Considering that revenues from seed sales and royal- ties are breeders’ main source of income, much is lost that could otherwise be rein- vested in R & D activities,” she adds. Heselmans shares that in principle the goal is same as in any crop: combine positive traits to retrieve genetic gain. In case of potatoes to be marketed as vegetative crop there are no hurdles like inbreeding to reach homozygosity. This hurdle has to be taken in case route of F1-hybrid true potato seed (TPS) breed- ing is chosen. “Clonal multiplication of potatoes does require more time (factor 8-10) compared to true seed F1 hybrids. Overall, complexity of genetics of the nowadays cultivated potato is a chal- lenge due to its tetraploid and heterozy- gote nature, this applies for whole field of potato breeding,” he says. IMPORTANT BREEDING GOALS IN THE POTATO BREEDING PROGRAMS The potato market is not one market says Backx. Potato for processing (starch, crisps, French fries) requires other char- acteristics than the potatoes for the fresh consumption. For processing, items like colour, success in the processing and the efficiency in the factory are important. Also, taste, length, etc. “Those words translate easily in a long list of character- istics one has to search for. Next to that it needs yield, disease resistance/tolerances etc. for the grower. Can you store and handle the variety or not? Can you har- vest the variety mechanically? Can you produce seed potatoes of that variety? All those items are important“ he states. “On the other hand, for the fresh market, the taste, the skin, the colour, the appeal etc. are important. The fresh market is very diverse. Different areas have different preferences and consumers like to have potatoes for firm cooking, or to make mashed potatoes, or home French fries. All those uses require other characteris- tics. Therefore, we have clearly defined for what markets we like to create varie- ties and what selection criteria we need to score. For every sub-segment of the market, it is a long list of characteristics.” In short, Prigge says those include quality, agronomic performance, and disease resistance. “In reality, there are more than 50 traits that our potato breed- ers take into account during the selection process, which means that the selection intensity per trait is quite low. We develop improved potato varieties for many potato sectors, mainly the crisp and French fry industry, starch industry, and the retail sector, all on a global scale. Hence, next to a set of common goals like early maturity or yield capacity for all segments, there are always additional goals specific to the demands of a certain market segment,” she adds. According to Heselmans, yield, stability, resilience and quality in crop and processing are the most important. Potato crops grow for a period of 80-150 days exposed to climatic shocks and dis- eases. Then, in many regions, part of the crop has to be stored for a long time. “To have a reliable result of the potato crop within the whole chain it is a challenge to combine all these factors. Sustainability is the key factor in decision making in potato breeding.” For Bandsma, the most impor- tant goals are underwater weight (high dry matter content), early to medium early maturity (early tuberisation is also OK), a strong tolerance against heat and drought, and usefulness for French fries, crisps, export varieties and table potato (yellow fleshed). “Potato is attacked by several diseases, such as Late Potato berries after crossing (Source A. de Nijs & Zn B.V.) blight, Common Scab, Silver Scurf and Rhizoctonia, and many others, so we need a good resistance against those diseases.” Smeenge lists yield, consumer-accept- ance, resistance to diseases, adaptation to different climates and usefulness for table, crisps and French fries as the most impor- tant breeding goals for his company. FINDING THE GENETIC DIVERSITY FOR DISEASE RESISTANCES “We are shareholders of the breeding company FOBEK, and they are making crosses based on our wishes. They have quite a genetic diversity for resistances. They are getting their genetic diversity from their own seed lines/varieties, making their own crosses, backcrosses and cooperation between different com- panies” says Bandsma. “Secondly, we work with free hobby breeders. They also have a genetic diversity for the genes. They get their genetics from their own seed lines/varieties, making their own crosses, working together with other hobby breeders and trying to get seed lines/varieties from the potato compa- nies. Our goals on resistances are potato cyst nematodes (PCN), wart disease, virus, common, scab and late blight.” For Prigge, the relevance of a dis- ease for the potato breeding programme depends on the anticipated market. “For example, at the moment resistance to the white nematode Globodera pallida is in high demand for varieties for European farmers, no matter what market seg- ment. New and highly virulent nematode strains have been found which had over- come resistance of the commonly used resistant varieties. In this case, we return to the vast collection of potato relatives that are held in genebank collections to identify genotypes that are resistant against these more virulent G. pallida strains and try to introgress these loci Potato quality trials for crisps, fries and cooking (Source Solana)