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Improved rust resistance

Project members: Prof. Jan Stenlid, Ass. Prof. Berit Samils

Rust fungi are severe pests in many agricultural crops. Also in willow plantations a leaf rust fungus (Melampsora larici-epitea) has shown to cause great damage. Production losses of up to 40% have been estimated in susceptible varieties. In order to maintain a high production level it is important that the cultivated varieties are resistant to the leaf rust. A problem is that the fungus causing leaf rust on willows has a high capacity to change and overcome resistance of the plant. This is especially true for the kind of resistance that is governed by a single or few genes which is common in cultivated crops. It is therefore preferable to utilize also other types of resistances that are governed by many genes and hence more complicated for the fungus to adapt to. The aim is that the cultivated willow varieties should have many different resistance genes and that it should be possible to combine these resistance genes in various ways in the varieties.

We are now working on developing molecular markers for the various resistance genes in Salix. To achieve this, we study Salix families consisting of hundreds of plants that are genetically different but closely related (siblings). By doing controlled infection experiments in growth chambers we are able to characterize various resistance reactions in these families. Examples of measurements are latent period and number and size of the fruiting bodies in the fungal attacks. We are also doing comparative assessments of rust resistance in the field on the same individuals. The data on resistance reactions are combined with the molecular marker data from the genetic maps for the Salix families. By QTL mapping we can find the regions in the genome where the resitance genes are located. When we have managed to identify markers close to the genes we can use them to examine which resistance genes are present in various Salix varieties and for selection of specific resistance genes in breeding of new varieties.

Download (printable): pdf Improved rust resistance

 

Updated 2016-11-29 |Berit Samils