Development of Multiplexed Marker Sets to Identify the Most Relevant Poplar Species for Breeding

Within the genus Populus, about 30 species are classified into six sections, of which some are cross-compatible. Besides naturally occurring hybrids, huge breeding programs have led to a high number of artificially produced hybrids, for which the determination of genetically involved species by morphological characteristics is often difficult. This necessitates the use of molecular markers for the identification of both maternal as well as paternal species, and in the case of complex hybrids, the genealogy. For this reason, we developed new chloroplast and nuclear markers for the differentiation of up to 19 poplar species, with one to 32 individuals per species regularly used in breeding programs based on already known barcoding, other chloroplast regions, and nuclear genes of interest. We developed methods to identify species by either species-specific nucleotide variations or, when no initial information for the species was given, by using a set of markers either in a procedure of exclusion or in a multiplexed marker set. The developed markers can all be used with low-cost equipment, and some can additionally be applied using a genetic analyzer. We combined these markers in multiplexes for a very fast and easy-to-use application for the identification of poplar species and their hybrids