Identification of Tetraploid Potato Clones with Good Processing Quality among Genotypes with Reduced Zebra Chip Disease Symptomatology

Zebra chip (ZC) disease caused by the bacterium ‘ Candidatus Liberibacter solanacearum’ (Lso) and vectored by the potato psyllid ( Bactericera cockerelli Šulc.) inflicts significant yield and quality losses in potato. Potato plants infected with Lso produce tubers with an internal brown stripe pattern that is unacceptable to the potato processing industry. Potato varieties tolerant of ZC disease could reduce yield and quality losses caused by the disease, as well as diminish insecticide usage to control potato psyllids. Tetraploid potato clones selected from breeding programs in the US were screened in Texas under both greenhouse and field conditions. Chipping quality in tubers harvested from plants infested with Lso-infected psyllids and those harvested from from non-infested plants were compared, and tuber symptoms associated with ZC disease were evaluated. Clones showing good chipping quality and promising ZC tolerance in the greenhouse and first field trials were independently tested in a second field trial. Clones of the A07781 and TX12484 families consistently showed good processing quality and ZC tolerance over multiple evaluations. These findings indicate that good processing clones with tolerance to ZC disease are available. These clones could be used by potato breeding programs as parents and could also be used to study the genetics of tolerance to ZC disease.