Microsatellite genotyping in New Zealand's poplar and willow breeding program : fingerprinting, genetic diversity and rust resistance marker evaluation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Plant Breeding at Massey University, Palmerston North, New Zealand
Poplars (Populus spp.) and willows (Salix spp.) are the most employed sustainable soil stabilisation tools by the pastoral sector in New Zealand. The poplar and willow breeding program at the New Zealand Institute for Plant & Food Research Limited (PFR) supports and improves the versatility of poplars and willows as soil stabilisation tools. Good germplasm management involves being able to accurately and objectively identify breeding material and characterise genetic diversity and relationships. Poplar rust is the primary pathogen of concern for the breeding program and evaluating candidate resistance markers could improve selection efficiency. We employed microsatellite markers to fingerprint and characterise the genetic diversity of the germplasm collection. In addition, we also evaluated SSR marker ‘ORPM277’s potential usefulness as a molecular marker to screen for rust resistance in New Zealand. We found that most microsatellite markers utilised in this study were moderately to highly polymorphic with Polymorphic Information Content values averaging 0.482 and 0.497 in the poplar and willow collections respectively. A DNA fingerprinting database was generated that differentiated between 95 poplar accessions and 197 willow accessions represented by 19 and 55 species groups respectively. Genetic variation was high and very similar in both poplar and willow groups, with the main source of variation coming from within genotypes. No correlation was found between phenotypic and genotypic rust resistance data using the ORPM277 microsatellite marker.