Intergeneric Transfer of Simple Sequence Repeat Molecular Markers for the Study of Chaenomeles as Fruit Crop Breeding Material

The genus Chaenomeles, part of the subfamily Maloideae within the Rosaceae family, comprises five recognized species and has long been valued for its ornamental qualities. However, the use of Chaenomeles japonica as a fruit crop is relatively recent, with its introduction into targeted breeding activities only occurring in the 1950s. Due to this, genetic information on the genus remains limited, and the application of molecular markers in crop breeding and further development have been narrow, relying primarily on non-specific marker applications in germplasm analysis. One potential solution is the transfer of molecular markers between genera, specifically from the related Maloideae genera. This study aimed to test the transferability of SSR markers developed for Malus to Chaenomeles, and to analyze the structure of available Chaenomeles germplasm. By including 74 Chaenomeles genotypes, 95 SSR markers originally developed for Malus were tested, with 25 proving effective for characterizing Chaenomeles germplasm. These adapted SSR markers successfully differentiated among Chaenomeles species, including Chaenomeles japonica, Chaenomeles speciosa, Chaenomeles cathayensis, and hybrids like Chaenomeles × superba and Chaenomeles × californica. The markers demonstrated high stability and repeatability, indicating their suitability for large-scale genetic research, species composition assessment, and breeding material evaluation. Given the limited studies on SSR markers in Chaenomeles, this research lays the foundation for further exploration, potentially expanding into the genetic diversity assessment and trait screening for breeding. As genetic research on Chaenomeles is still in its early stages, the development of additional markers will be crucial for advancing this crop.