A genetic linkage map of an inter-specific diploid Fragaria BC1 mapping population and its comparison with the Fragaria reference map (FV C FN)

We have produced a reduced linkage map of a diploid Fragaria backcross progeny (F. vesca [F. vesca F. viridis]) denoted 815 x 903BC from 31 microsatellite (SSR) and two gene-specific markers selected from the diploid Fragaria reference map FV FN. The 33 sequence tagged-site (STS) markers selected, segregated in seven linkage groups, and marker order was conserved between FV FN and 815 x 903BC. Significant segregation distortion, observed on three of the seven linkage groups, was accompanied by a reduction in observed recombination frequency and, therefore, genetic distance between markers mapped in these linkage groups. However, this distortion did not affect marker order compared to FV FN and may indicate non-random chromosomal divergence during speciation in Fragaria. Our findings indicate that no major genome reorganisation has occurred during speciation in the genus, and suggest that STS linkage maps of other Fragaria populations, including those of the cultivated strawberry F. ananassa, could be constructed using the diploid Fragaria reference map FV FN as a standard reference point.