Resistance to the potato cyst nematode (Globodera rostochiensis) of tetraploid potato clones with different genetic backgrounds

Resumo

Fifteen new potato clones were screened to pathotype Ro2 of the potato cyst nematode, Globodera rostochiensis. One dm} clay pots were filled with soil infested with 17 eggs of the nematode/em} and six of them were planted with tubers of each clone and arranged in a glasshouse at 18-22 0c. When thirty-five days old, all plants were uprooted and nematode infestation of the roots evaluated according to a visual score and by extracting all nematode developmental stages. All clones were invaded by a large number of nematode specimens. However, in seven potato clones (S90-1575-5, S90-157-19, S90-157-27, S90-157-28, S90- 157-49, S90-164-1, S90-164-7) most of the nematodes (71.4-94.8%) remained at the second stage and none or only a few developed further to become third, fourth and adult female stages and cysts. These clones were considered resistant.