Improving Sclerotinia resistance to assist red clover breeding

General introduction

Clover cancer, a disease caused by the fungus Sclerotinia trifoliorum, can cause heavy damage to red clover crops during winter. The disease is difficult to control and completely resistant varieties do not exist. Breeding for resistance is slowed down by a lack of artificial infection assays (bio-tests). Moreover, little is known about the genetic diversity of the pathogen. In this project, genetic diversity and aggressiveness of the pathogen are studied on a European scale. Additionally, we construct a new bio-test and examine the inheritance of Sclerotinia resistance in red clover.

Research approach

First, the genetic diversity of a large number of Sclerotinia isolates from various countries in Europe is studied using AFLP. Secondly, a new high-throughput bio-test is developed that can be used in breeding programmes. This bio-test is used to compare the aggressiveness of a subset of isolates and to allocate possible sources of resistance among a large collection of red clover varieties. Finally, pair crosses are made between resistant and susceptible plants. A progeny screening will give an estimate of the heritability and the number of major genes involved.

Relevance/Valorisation

Research results are published in scientific journals and are used in ILVO's red clover breeding programme. This may lead to new red clover cultivars with sustainable resistance against clover cancer.