Fecha de publicación: 05/10/2024 Fuente: ISHS (International Society for Horticultural Science) Post date: Saturday 5 October 2024
Author:
ISHS Secretariat

Ilex crenata or box-leaved holly has gained popularity for use as an ornamental shrub for topiary and hedges in Western Europe. I. crenata prefers acidic soils, which makes it less than ideal for the typically pH-neutral private garden. When grown in neutral pH soils, I. crenata experiences problems with nutrient uptake. A higher soil pH also creates favorable conditions for the soil-borne fungus Berkeleyomyces basicola, the causal agent of black root rot. This combination of abiotic and biotic stress poses a serious threat to I. crenata planted in gardens. More resistant and tolerant cultivars can be developed through breeding. Up to now, new cultivars of I. crenata have primarily resulted from lucky finds, but interest is growing in targeted breeding to improve tolerance or resistance to abiotic and/or biotic stress. In this study, rooted cuttings of 15 genotypes were planted in substrate with pH 4.1 and 7.5, and a spore suspension was mixed into the substrate to inoculate the roots with B. basicola. All treatments were compared to control plants in a low pH substrate without inoculation. Evaluated parameters were root and shoot weight, chlorophyll fluorescence and a root score based on the level of fungal root necrosis. Furthermore, a qPCR assay developed within this project was used to quantify fungal DNA in the plant roots. Our findings revealed that tolerance to high soil pH varied among the 15 genotypes tested, with one genotype showing significantly better tolerance. The genotypes also showed differences in tolerance to black root rot, but no genotypes showed resistance or a high level of tolerance. Furthermore, this study shows the efficacy of bioassays as a selection step in plant breeding programs. The better performing genotypes will now be used in crossbreeding and the pH and disease tolerance tested in the progeny using the same bio-assay.
Esther Geukens is a PhD student at Flanders Research Institute for Agriculture, Fisheries and Food and KU Leuven. She won the ISHS Young Minds Award for the best oral presentation at the V International Symposium on Woody Ornamentals of the Temperate Zone in Japan in April 2024. This research is funded by a Baekeland mandate (VLAIO).
Esther Geukens, ILVO, Caritasstraat 39, 9090 Melle, Belgium, e-mail: esther.geukens@ilvo.vlaanderen.be
The article is available in Chronica HorticulturaeTags: Ilex crenataCategories: Young Minds Award Winners