Development of YLM, a codominant PCR marker closely linked to the Yd2 gene for resistance to barley yellow dwarf disease

The Yd2 gene in barley provides protection against barley yellow dwarf luteovirus (BYDV), the most economically devastating virus of cereals worldwide. Because resistance assays to identify Yd2-containing individuals from breeding populations are difficult, we have developed a closely linked, codominant PCR-based marker for Yd2 using AFLP marker technology. The marker, designated YLM, can be amplified from barley genomic DNA prepared using a rapid and simple extraction procedure and, in a survey of more than 100 barley genotypes, was found to be polymorphic between most Yd2 and non-Yd2 lines. The YLM therefore shows excellent potential as a tool for selecting Yn2-carrying segregants in barley breeding programmes.