New set of microsatellite markers for the walnut hybrid progeny Mj209xRa and assessment of its transferability into Juglans genus

Aim of the study: The research was aimed to design microsatellite markers for genotyping and differentiation of trees from the walnut hybrid progeny Mj209×Ra. As a secondary objective, the transferability and classificatory capacity of some of these loci were assessed for Juglans genus.Area of study: The most widely spread walnut hybrid progeny used in Europe for wood production was used. Pure species from Juglans genus as Arizona black walnut (J. major (Torrey) Heller) and European or common walnut (J. regia L.), as well as a different hybrid Mj209xRa lots, were also included.Materials and methods: Genomic DNA from a hybrid tree was used for the construction of libraries enriched with dinucleotides repeats (CA/GA). From approximately 700 fragments containing SSR regions, 18 loci were finally selected for the genetic characterization. Eight of these genomic microsatellite markers were used to assess their transferability into Juglans genus. Main results: Despite the high degree of kinship of the hybrid progeny, it was possible to differentiate random trees with a low probability of error. Markers also allowed to differentiate unambiguously between Arizona black walnut and European walnut. They were even able to discriminate two hybrid Mj209×Ra lots with a high degree of certainty.Research highlights: This new set of microsatellites might be considered a complement for the markers published up to date to perform studies into Juglandaceae family.Keywords: Juglandaceae; wood production; genotyping; genotype identification; simple sequence repeats; SSR.