Development of DNA-based Markers for Enhanced Strawberry Flavour

Improvement of strawberry (Fragaria x ananassa Duch.) fruit flavour is one of the top priorities in the Australian Strawberry Breeding Program. This study aims to develop DNA-based markers closely linked to genes controlling strawberry flavour by integrating an innovative target enrichment technique known as Subtracted Diversity Array (SDA) with a conventional breeding method called Bulked Segregant Analysis (BSA). A subtracted genomic library was constructed using two commercial varieties (Albion and Juliette) and three promising breeding lines (07-102-41, 07-095-35 and 04-069-91) as tester and nine non-angiosperms (Dryopteris kuratae, Wollemia nobilis, Dicksonia antartica, Cupressus macrocarpa, Cycas revoluta, Asplenium australasicum, Blechnum tabulare, Ginkgo biloba, and Juniperus communis) as driver. A total of 291 clones specific to strawberry fruit quality were selected and printed on aminosilane-coated slides to produce a SDA. The DNA fingerprint unique to each strawberry genotype was generated by hybridizing the genomic DNA from the respective genotype onto the SDA. Hierarchical cluster analysis revealed that 07-102-41, 07-095-35 and 04-069-91 are genetically closely related whereas Albion and Juliette are more diverse than the others. To identify DNA markers associated with flavour compounds by BSA, the DNA of F₁ progenies from Juliette and 07-102-41 cross will be bulked according to two extreme phenotypes determined by gas chromatography-mass spectrometry (GC-MS) and hybridized onto the SDA platform. Significant differences of spots intensity between two bulks will be identified and their potential as molecular markers will be investigated.