Hi! My name is Daan Langendoen and I have been a part time PhD student at the laboratory of Nematology since March 2023. Besides my PhD project, I am working as Phytopathology Specialist at the starch potato breeding company Averis Seeds in Valthermond. Averis Seeds is a subsidiary company to Avebe and the funder of my PhD project.
Potato cyst nematodes (PCN) are plant parasitic nematodes that feed on potato roots. They include two species: Globodera pallida and G. rostochiensis. In the northern regions of the Netherlands PCN are among the most damaging biotic stresses, causing substantial yield losses. With the introduction of PCN resistant potato varieties, the amount of PCN infected soil has steadily declined in the Netherlands. However, infection rates seem to be increasing once more, probably due to a resistance breakthrough by G. pallida. A similar build-up of virulent populations might be happening in G. rostochiensis.
Potato breeding companies use multiple genetic sources for potato cyst nematode (PCN) resistance in their breeding program regularly. The resistance loci Grp1 and Gpa5 have been used extensively in cultivars such as Seresta and Iledher, but their resistance has been overcome by virulent G. pallida populations. Various known major resistance QTLs have great potential, but their durability has never been tested. In order to prevent resistance breaking of important resistance loci in the future, more research on alternative durable strategies is necessary.
Strategies to be tested include four major topics that could ultimately be combined. Firstly, some varieties are known to inhibit nematode hatching from cysts, which could be an interesting breeding trait. Secondly, highly resistant varieties often contain an increased allele dosage of resistance genes, yet a positive correlation has not been scientifically proven. Thirdly, undescribed resistance traits are available in wild Solanum accessions, which are yet to be genetically mapped. Lastly, in current breeding efforts PCN resistance QTLs are stacked in one variety which has a high breeding effort, and ultimately leads to resistance breakthrough. A plausible strategy could be to use multiple stacks of different PCN resistance genes in rotation. Using the results of this research, a breeding strategy can be formulated to combine known and yet unknown PCN resistance traits in a (hybrid) potato breeding program to combat or live with PCN in the future.