Molecular genetic linkage map for allotetraploid colonial bentgrass

Interspecific hybridization is a widely used approach to improve crop species. We are pursuing the possibility of using interspecific hybridization between the turfgrass species colonial bentgrass (Agrostis capillaris L.) and creeping bentgrass (A. stolonifera L.) for the improvement of resistance to the fungal disease dollar spot (Sclerotinia homoeocarpa F.T. Bennett) in creeping bentgrass. From a field evaluation of a backcross population, it appears that introgression of dollar spot resistance from colonial bentgrass to creeping bentgrass is possible. We used the backcross population to generate the first genetic linkage map for colonial bentgrass. The map length was 1156 cM and consisted of 212 amplified fragment length polymorphic markers and 110 gene-based markers. Colonial bentgrass is an allotetraploid species (2n = 4× = 28, A₁ and A₂ subgenomes). The map consisted of the expected 14 linkage groups, which could be assigned to either the A₁ or A₂ homoeologous subgenomes. Although there were dollar spot resistant individuals in the mapping population, no quantitative trait loci associated with resistance were detected.