Partial resistance to Erwinia carotovora SUBSP. carotovora and plant vigour among F1 hybrids of Zantedeschia cultivars

The potential of breeding Zantedeschia cultivars for resistance to soft rot caused by Erwinia carotovora subsp. carotovora (syn. Pectobacterium carotovorum subsp. carotovorum) was determined. Hybrids of six cultivars (`Back Magic`, Galaxy`, Pink Persuasion`, Sensation`, `Treasure` and `Florex Gold`) were screened using a non-destructive resistance test (leaf disk test) and scored different levels of susceptibility. Some hybrid families were less susceptible than the very susceptible reference `Florex Gold`, while all hybrid families were more susceptible than the partial resistant reference Z. rehmannii. The half-sib family of `Pink Persuasion` was more resistant, but less vigorous than the half-sib family of `Florex Gold`. We concluded that resistance and vigour may be negatively correlated in the deployed cultivars and that resistance should be bred from other sources than the used cultivars