Development and Application of Molecular Markers in Gerbera (Gerbera hybrida)

Gerbera is one of the most important floricultural crops in the world.  Gerbera breeding is active in a number of countries.  Gerbera breeders have expressed strong interest in developing and applying molecular markers to facilitate the selection of breeding parents and lines with resistance to fungal diseases such as powdery mildew and Botrytis gray mold, differentiate gerbera cultivars, and protect breeders’ rights or plant patents of new gerbera cultivars.  In response to these needs, we have developed microsatellite, sequence-characterized amplified region, and cleaved amplified polymorphic site markers for use in gerbera breeding.  These markers have proven to be highly discriminatory in distinguishing gerbera cultivars.  UPGMA clustering and population structure in commercial gerbera cultivars were found to be largely corresponding to breeding approaches and/or propagation methods, rather than cultivar series, breeding company, or country of origin.  Bulked segregant analysis has identified putative molecular markers that appeared to be associated with powdery mildew resistance.  QTL mapping using these markers revealed the existence of one locus that account for up to 71% of the variance in powdery mildew resistance in two backcross populations.  Next-gen sequencing is being pursued to discover and develop single nucleotide polymorphism markers for use in gerbera breeding and genetic studies.