Assessing genetic structure and diversity in natural populations of <i>Eucalyptus bosistoana</i> : insights from SNP genotyping for New Zealand breeding trials

Eucalyptus bosistoana (Myrtaceae) is a breeding species of NZDFI (New Zealand Dryland Forests Innovation), which aims to establish forestry plantations of ground-durable, high-value hardwoods in New Zealand. For this purpose, plants from E. bosistoana seeds collected from natural source locations in Australia between 2008–2012 have been used since 2009 to establish breeding trials in New Zealand. To inform the NZDFI breeding programme, leaf samples of 177 E. bosistoana breeding families were genotyped using a Eucalyptus 72K single nucleotide polymorphism (SNP) Axiom array. This was done to identify patterns of genetic structure among E. bosistoana breeding families and to assess the genetic structure and diversity of the natural source populations from which their seeds were obtained. PCoA and STRUCTURE analyses indicated that the E. bosistoana seeds were obtained from three natural source populations with similar levels of genetic diversity. Weak genetic structure among most natural source locations of E. bosistoana within these populations was observed, and families from nearby source locations were generally genetically more similar to each other than to those established from more distant locations. We also found that some families in the E. bosistoana breeding programme represent E. melliodora. These combined genetic patterns provide the genetic basis for establishing, maintaining, or improving NZDFI’s E. bosistoana breeding populations.