RESISTANCE OF POTATO VARIETIES TO FIELD POPULATIONS OF THE POTATO CYST-NEMATODE GLOBODERA-PALLIDA IN THE NORTHEASTERN PART OF THE NETHERLANDS

In the northeastern part of the Netherlands starch potatoes are grown intensively. From 392 fields in that area, soil samples that contained the potato cyst nematode Globodera pallida were used to analyze the r esistance of 7 varieties of starch potatoes. Differences and similarit ies in resistance of the varieties to the field populations of G. pall ida could well be explained by their descent from distinct sources of resistance. The G. pallida-populations that showed a relatively high v irulence to the varieties Producent, Elles, and Darwina were not equal ly distributed over die area, but were confined to a small number of r egions.