Veredeling van de aardappel op resistentie tegen Heterodera rostochiensis Wollenweber

Thousands of plants of tuber-forming species of the genus Solanum were tested for resistance to the potato-root eelworm. Much attention was given to breeding for resistance by using resistant andigenum lines in crosses with S.tuberosum. In 1952 for the first time large numbers of resistant andigenum seedlings (numbers CPC 1673 and 1685) could be crossed among themselves and with susceptible potato varieties. The explanation of the observed segregations into resistant and susceptible was based on the hypothesis that resistance was due to one dominant gene H and that a tetraploid inheritance scheme could be applied.Resistant offspring of CPC 1673 was tested at the Estación Experimental Agricola de la Molina, Peru. All the resistant offspring were severely attacked by the potato- root eelworms occurring in the soil of 'Maco Farm'. Therefore the Peruvian parasite, at least in one place, is of a different race from that. in the Netherlands.In Scotland an aggressive race of the parasite had been found in some places. This race multiplied profusely in resistant potato varieties derived from CPC 1673.It was advised that the legal restriction in the Netherlands against growing potatoes on the same field be provisionally maintained