Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Jernej Jakse x
Clear All Modify Search

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.

Free access

Onion (Allium cepa L.) bulb color is controlled by at least five major loci (I, C, G, L, and R) and seedcoat color by one locus (B). The authors developed families segregating for bulb and seedcoat colors, simple sequence repeats (SSRs), and single nucleotide polymorphisms (SNPs) in genomic amplicons of dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). The B and C loci were linked to SSRs on chromosomes 1 and 6 respectively. For all of three families, SNPs in DFR cosegregated with the R locus conditioning red bulb color. In the family from B2246 × B11159, red bulbs versus yellow bulbs were controlled by DFR and a locus (L2) linked at 6.3 cM to ANS. The authors propose that yellow bulb onions have been independently selected numerous times and that yellow populations carry independent mutations in structural or regulatory genes controlling the production of red bulb color in onion.

Free access

The commercial production of onion (Allium cepa L.) inbreds, hybrids, and open-pollinated (OP) cultivars would benefit from a robust set of molecular markers that confidently distinguish among elite germplasms. Large-scale DNA sequencing has revealed that single nucleotide polymorphisms (SNPs), short insertion-deletion (indel) events, and simple sequence repeats (SSRs) are relatively abundant classes of codominant DNA markers. We identified 398 SNPs, indels, and SSRs among 35 elite onion ulations and observed that all populations could be distinguished. Phylogenetic analyses of simple-matching and Jaccard's coefficients for SSRs produced essentially identical trees and relationships were consistent with known pedigrees and previous marker evaluations. The SSRs revealed that elite germplasms from specific companies or breeding programs were often closely related. In contrast, phylogenetic analyses of SNPs and indels did not reveal clear relationships among elite onion populations and there was no agreement among trees generated using SNPs and indels vs. SSRs. This discrepancy was likely due to SNPs and indels occurring among amplicons from duplicated regions (paralogs) of the onion genome. Nevertheless, these PCR-based markers will be useful in the quality control of inbred, hybrid, and OP onion seed lots.

Free access