CU LTIVATION AND TECHNOLOGY Variety Presentation Days 2019: main objectives in breeding vary widely ! Colm McDonnel, IPM, Dublin (Ireland): ‘If you want to be successful in breeding, it's especially important to have a vision of the future. ‘What we, as growers, always try to aim for is to focus our breeding on demands from the market. However, the problem is always that you can only answer new questions in eight to twelve years’ time, because it takes at least that long to develop a variety. Some issues have been around for a long time, such as Phytophthora and nematode resistance. If you've been in the breeding business for a long time, you've undoubtedly been working on it for many years and that's also the case with IPM. But when it comes to suddenly emerging problems such as the recent virus issues, not every breeder has a readily-available answer. That’s the tricky part of our line of work. If you want to be successful in breeding, it's especially important to have a vision of the future. Years ago, for example, we already realised that crop protection chemicals would be restricted in the EU-5 countries. We’re losing sprout inhibitors, pesticides, nematicides, fungicides and insecticides. There will be fewer and fewer of all these products available soon. So, one day, there’ll be a demand for varieties that can survive without these products. Climate change is another factor that we saw coming many years ago and which we started to address in our breeding work. The result of this is that we now have a list of new varieties that you can definitely call robust. They can take a beating when it comes to climate extremes and they also harbour the desired resistances that require less spraying. A still young variety that contains all these characteristics is our Buster. When I go through the rating list, I see, for example, a 9 for nematode resistance, a 5 and 8 for Phytophthora resistance and an excellent rating for taste. Furthermore, this variety is easy to grow and also provides plenty of ‘We now have a list of new varieties that you can definitely call robust.’ tubers for the cultivation of seed potatoes. It’s quite a challenge to get this far with a variety, but it’s the type we have in mind at the moment.’ ! Sjefke Allefs, Agrico Research, Bant: ‘It’s imperative that we ‘We’re currently paying a lot of attention to our Next Generation varieties, whereby Phytophthora resistance is an important characteristic. A ware variety we have high expectations of in this context is Levante. However, given the virus problems we have this season, we need to incorporate a decent resistance into our varieties for this. I think that the problems with viruses are mainly caused by the scaling up in seed potato cultivation, combined with a number of hot summers and favourable conditions for virus infections. This increase in scale is not reversible. That’s why it’s important to crossbreed virus resistance into varieties in order to keep seed potato cultivation reliable for the future. Traditionally, as commercial breeders, we were told that we shouldn’t do too much about virus resistance. The fact that a variety like Santé is immune to viruses turned out to be commercially undesirable. The variety didn’t degenerate enough in the sales areas. At the moment, however, it’s important that we increase the level of resistance, but we must stay away from immunity. This is technically possible, because there are intermediate gradations in resistance. We’re now investigating how genetics currently relates to virus-related problems that occur in practice. What we’re seeing is substantial variety differences. We already have markers for the major genes, but how the intermediate levels relate is not yet clear. It’s important to find this out, because it allows us to determine the virus resistance at an early stage. At the moment there’s still a lot of work to be done to establish good resistance figures. We have to plant new varieties between diseased plants, harvest the tubers and have 22 Potato World 2020 • number 1 What is your most important focus in your breeding work at the moment ? Pagina 21

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