Fine Mapping of the Dw7 Dwarfing Gene in Oat

Dwarfing genes have been of great value for improving productivity in modern cereal breeding programmes but as yet few such genes have been available for oat with only two, Dw6  and Dw7, being widely used. Here, we have used a variety of molecular markers and two independent biparental populations to map the semi-dominant Dw7 locus with the closest linked marker showing linkage of less than 0.5cM. Positioning of markers on the Avena atlantica diploid zipper and screening of linked gene content provided a number of potential candidate genes. An indel marker derived from one of these showed perfect co-segregation with reduced height in the relevant mapping populations, and was nearly perfectly associated in a range of varieties tested. The presence of the Dw7 associated allele in some old varieties indicates that the polymorphism is not directly causal, however.