Inheritance of resistance towards Septoria nodorum blotch in winter wheat, assessment by conventional and alternative screening techniques.

摘要

The aim of this project is to develop alternative breeding strategies for selection against Septoria nodorum blotch (SNB) caused by the fungal agent Stagonospora nodorum. In previous studies, crude extracts of S. nodorum were used as selective agent,allowing to distinguish resistant and susceptible cultivars in an in vitro test with zygotic (Keller et al., 1994) and mature wheat embryos (Wicki et al, 1999). Our project aims to improve the in vitro test and thereby to have a better understand about involved pathotoxins and genetic background of resistance. For that purpose culture conditions leading to a selective extract were determined. Further steps include fractionation by HPLC of the extract that would enable to choose the most selective components and to characterise it chemically. Special attention will be given to the application of the in vitro test for screening 226 Recombinant Imbred Lines (RILs) derived from the cross of a resistant spelt variety (Oberkulmer) with a susceptible wheat cultivar (Forno). Quantitative traits loci (QTLs) calculated on this bases will be completed by QTLs calculations based on resistance at a seedling plant state. The calculated QTLs will be correlated with the QTLs calculated on the basis of field evaluation (results to be presented) enabling us to conclude, whether the in vitro test using crude extracts and seedling plants assessment is a useful tool for breeding programs. Furthermore we aim to develop molecular markers linked to these QTLs for molecularassisted selection.