Construction of Two Sweet Cherry Linkage Maps in Two Populations Derived From Commercial Cultivars

Despite the agronomical importance and high synteny with other Prunus species, breeding improvements for cherry has been slow compared to other temperate fruits, such us apple or peach. The recent release of the peach genome v1.0 provides an excellent basis for cherry genetic and genomic studies. The creation of saturated genetic linkage maps in well-assessed segregating populations would be  a valuable tool for breeders and geneticists. Using two sweet cherry intraspecific crosses between ‘Black Tartarian’ × ‘Kordia’ (BT × K) and ‘Regina’ × ‘Lapins’ (R × L), two high-density genetic maps of sweet cherry (Prunus avium L.) were constructed. Markers were primarily single nucleotide polymorphism (SNP) markers genotyped using the Illumin Infinium 6K cherry BeadChip developed within the RosBREED consortium and simple sequence repeat (SSR) markers with known position on the peach (Prunus persica L.) genome v1.0. For BT × K and R × L, 89 and 124 F1 plants were used for linkage mapping, respectively. A total of 5,696 SNPs markers were tested in each population. As a result of these analyses, 822 and 728 markers were mapped into eight linkage groups in BT × K and R × L, respectively. The resulting maps spanned 613.8 and 623.7 cM with an average distance of 0.75 and 0.86 cM between adjacent markers in BT × K and R × L, respectively. The maps displayed high synteny and colinearity between each other and with the Prunus T × E reference map for all eight linkage groups (G1-G8). Segregation distortion was detected in a large region on G1 due to an unknown cause in both populations, and in a region of G6 surrounding the self-incompatibility allele of Lapins in R × L. These maps provide a useful tool for investigating traits of interest in sweet cherry and represent a qualitative advance in the understanding of cherry genome and its synteny with peach.