RE SEARCH Searching for root properties for more robust potato varieties N o, it’s not the Wageningen campus we’re visiting this time to hear more about potato research. In the Linnaeusborg on the Zernike Campus of the University of Groningen (RUG), Jan Henk Venema has been working on the roots of the potato plant since 2017. In the greenhouse, which is built against the building, he shows pots of coarse sand in which various potato varieties are just emerging. In the coming weeks, they will be exposed to water with different salt concentrations, after which he will map out how the root system reacts to this. The researcher, who was trained as a plant physiologist, works in a research group that studies interactions between plants and their environment, both wild and cultivated crops. A few years ago, Venema worked on a method for the selection of robust rootstocks in tomatoes, which also revolved around the development of roots. With the help of POP3 money (European money distributed through the provinces), this research is now being extrapolated to the potato. The need for robust varieties is growing in potato cultivation, too, due to increasing weather extremes, advancing salinisation, and increasingly stringent fertilisation standards. This is a three-year research project involving three northern breeders: Fobek, Biemond and Mansholt. They supplied the varieties that are used in the research and know the differences in the field. Venema focuses on the fundamental knowledge. ‘We want to map out how the plant adapts its root system and on which physiological differences they are based,’ explains the researcher. ‘When we know this, we’ll be able to look more specifically at the genes that regulate this, and the breeders will be able to find stronger varieties more quickly, through marker technology. Furthermore, there are still many questions about exactly how potato plants deal with abiotic stress, such as drought, salinity, lack of nitrogen and too much water. We’d like to know the mechanisms behind it.’ Pampered Last year, Venema started screening around thirty varieties, which he subjected to different levels of stress. What immediately stood out was that varieties under ideal growing conditions show few differences in the root-sprout ratio. ‘As long as you pamper them, the variation is small. The ratio between the What happens to the roots if a potato plant has wet feet for a long time? The left box in the photo shows that. On the right a control plant.It can be seen that in particular the deeper basal roots (left pile of roots per plate) do not survive due to lack of oxygen. Of the higher-formed stolon roots (the rightmost pile of roots per plate) survive more. It is to be expected that varieties with more of this type roots, more resistant to flooding. 6 Potato World 2019 • number 4 Pagina 5
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