TOLERANCE TO CYST-NEMATODE ATTACK IN COMMERCIAL POTATO CULTIVARS AND SOME POSSIBLE MECHANISMS FOR ITS OPERATION

Ten commercial potato cultivars, one resistant to Globodera rostochiensis Ro1 and the others susceptible, were grown on two sites, one heavily infested with G. rostochiensis Ro1 and the other uninfested. The only resistant cultivar, Maris Piper, suffered least yield loss; of the susceptible cultivars Pentland Crown suffered least loss and the early maturing Maris Peer most. The degree of tolerance to nematode attack was related to the amount of calcium accumulated in the dry matter of plants growing on the uninfested site and this relationship may have been due to the efficiency with which different cultivars used water. Other mechanisms which might lead to tolerance include reduced ability to stimulate hatching, reduced root invasion by juveniles and the formation of fewer adult females. © 1979 BRILL.