Resistance to Meloidogyne chitwoodi Identified in Wild Potato Species

Meloidogyne chitwoodi (Columbia root-knot nematode, CRKN) can cause serious damage in potato production systems, decreasing tuber value in the fresh market and processing industries. Genetic resistance to CRKN was first identified from the wild diploid potato species Solanum bulbocastanum accession SB22 and was successfully introgressed into tetraploid potato breeding material. To expand the base of genetic resistance, 40 plant accessions representing nine wild potato species were screened for their resistance to M. chitwoodi. Greenhouse screening identified fifteen clones from S. hougasii, one clone from S. bulbocastanum, and one clone from S. stenophyllidium with moderate to high levels of resistance against three isolates of M. chitwoodi. Geographical mapping showed that the resistance sources identified in this and previous studies primarily originated in the states of Jalisco and Michoacán in west-central Mexico. These new sources of resistance will be introgressed into elite potato populations to facilitate the development of potato cultivars with durable resistance to M. chitwoodi.