Construction of genetic linkage maps of ‘Fina Sodea’ clementine (Citrus clementina) and Byungkyul (C. platymamma), a Korean landrace, based on RAPD and SSR markers

In this study, genetic linkage maps were constructed for ‘Fina Sodea’ clementine (Citrus clementina) and Byungkyul (C. platymamma) using 152 F₁ clones as a mapping population. Reference-guided whole-genome sequencing, using next-generation sequencing technology, along with 82 randomly amplified polymorphic DNA markers and seven genomic simple-sequence repeat (gSSR) loci, mined 41 polymorphic gSSR loci from the direct comparative analysis. The generated linkage map for ‘Fina Sodea’ clementine contained 22 markers distributed into 10 linkage groups, with a total length of 417.7 cM and an average interval of 19.0 cM. The map for Byungkyul contained 57 markers distributed into 10 linkage groups, with a total length of 684.9 cM and a smaller average interval of 12.0 cM. Comparison of shared gSSR markers between the two maps identified collinearities, such as linkage groups B3 and C7 and groups B9 and C7. The newly developed gSSR markers greatly enrich the limited amount of gSSR markers in Citrus, providing markers that can be useful for comparative mapping and other genetic studies.