2017 ASHS Annual Conference

In the genus Pyrus, High-density genetic linkage maps have been constructed with an effort to identify quantitative traits loci (QTLs), evaluate whole genome structure, and apply to marker-assisted selection. In this study, a population of 93 progenies of ‘Whangkeumbae’ (P. pyrifolia) and ‘Minibae’ (P. hybrid) was used to construct a saturated linkage map using genotyping by sequencing-based 2,331 SNP and 12 InDel markers according to the pseudo-testcross mapping strategy. For the detection of InDel markers, ‘Whangkeumbae’ and ‘Minibae’ were aligned to the pear whole genome sequence of Chinese pear ‘Suli’ (P. bretschneideri). After grouping, 17 strongly linked groups consisted of 982 SNP and 2 InDel markers in ‘Whangkeumbae’ and 907 SNP and 5 InDel markers in ‘Minibae’, respectively. The map for ‘Whangkeumbae’ consisted of 988 loci on 17 linkage groups (LGs) over totals of 1,111.6 cM, with an average distance of 1.13 cM between markers whereas that for ‘Minibae’ included 921 loci encompassing a genetic distance of 1,293.5 cM, with an average distance of 1.40 cM. The shortest LG of ‘Whangkeumbae’ was 10.0 cM in LG17, while that of ‘Minibae’ was 30.3 cM in LG2. However, the longest LG of ‘Whangkeumbae’ was 105.1 cM in LG10, while that of ‘Minibae’ was 119.2 cM in LG11. In our results, 3 InDel markers fitting a Mendelian fashion were not mapped, indicating a relatively unevenness of restriction sites across the genome. This genetic map should be continuously integrated with published SSRs for the construction of consensus genetic linkage map.