Evaluation and application of molecular probes for incorporating alien-direved resistance to Barley yellow Dwarf Virus (BYDV) into Bread wheats (1996-99)

Ms. Ligia Ayala-Navarrete, CIMMYT, Lisboa 27, 06600 Mexico D.F.
Prof. I. Potrykus, Institute of Plant Science ETHZ, 8092 Zürich

Goal
This project concerns a disease in which little has been achieved in the realm of true resistance (as opposed to tolerance). The novel, alien sources available today warrant the rapid incorporation of true resistance into selected wheat germplasm.

Tolerance is certainly not a sufficient or even desirable mechanism of defense. In effect, tolerance could depend on genes that do not impede virus multiplication, which would have no effect on reducing the virus reservoir and might even increase it through increased biomass (Plourde et al. 1992). Finding and incorporating true resistance is therefore a primary aim of CIMMYT’s wheat research.

The identified resistance involves a segment from an alien source which can easily be characterized within a bread wheat genotypic background using molecular markers. Therefore, such markers could be used as selection criteria for the presence of the introgressed alien segment and, ultimately, resistance to BYDVs.

Objectives

• To develop wheat germplasm resistant to BYDVs.
• To develop a more effective and efficient breeding approach for BYDV resistance based on molecular marker selection technologies.
• To provide information on the genetics of resistance and its stability resulting from the eventual combination of several sources of BYDV resistance/tolerance genes.