Pink rot resistance in celery (SCLEROTINIASELDER)

In Flanders celery is an important niche market, both in the fresh market and in frozen foods. Pink rot by Sclerotinia can develop and damage celery plants at any stage of growth and storage, although most losses occur at harvest time. In this project we search for resistance against this fungus with bioassays in isolation for screening on genetically diverse material. We keep resistant genotypes alive for use in further breeding towards new, more tolerant varieties.

In a first step we collect sclerotia (the survival organs of the fungus) in a production field and develop conservation techniques for them. We also can grow the fungus in vitro and induce sporulation. We use these spores together with mycelial fragments in a bioassay for the infection on celery plants with a diverse genetic background. In the next step we maintain the resistant plants and cross them in a half-sib family breeding sheme towards new candidate varieties (candivars) of celery. Finally, we test the candivars in a production field and evaluate their resistance and agricultural value.

Research information about epidemics of pink rot as well as the growth of the fungus on isolated celery plants leads to a useful protocol for further investigation and screening. Knowledge about the critical factors and values of climate, nutrition, etc. are important here. Field experiments with the more resistant material confirm the accuracy of the bioassay. With the most resistant plants, we aim to create new varieties of celery that guarantee yield security for the growers.