Microsatellite marker for homozygosity testing of putative doubled haploids and characterization of Mimulus species derived by a cross-genera approach

Abstract

A codominant marker for homozygosity testing and species discrimination needed in breeding programs was developed and applied to different Mimulus L. species and cultivars. Degenerative primers used to amplify intron 10 of topoisomerase 6 subunit B (top6B) in distant species also amplified the locus in all analyzed Mimulus species. The sequences obtained revealed the presence of a microsatellite motif and were used to design a specific microsatellite primer pair, Mim-top6B, for Mimulus species. The microsatellite marker showed a high degree of polymorphism in Mimulus species, and the heterozygous nature of most M. aurantiacus Curtis cultivars. The marker was further used to analyze putative doubled haploids of M. aurantiacus and showed that all but one was heterozygous, indicating their hybrid origin.