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Single Nucleotide Polymorphisms in Linkage Disequilibrium with the Male-fertility Restoration (Ms) Locus in Open-pollinated and Inbred Populations of Onion
- Havey, Michael J
- Journal of the American Society for Horticultural Science 2013 v.138 no.4 pp. 306
- alleles, chromosome mapping, cultivars, genetic markers, genotype, hybrids, inbred lines, isogenic lines, linkage disequilibrium, loci, maintainer lines, male fertility, onions, open pollination, single nucleotide polymorphism
- Maintainer lines are used to seed propagate male-sterile lines for the development of hybrid-onion cultivars. The identification of maintainer lines would be more efficient with molecular markers distinguishing genotypes at the nuclear male-fertility restoration (Ms) locus. Ms has been mapped to chromosome 2 of onion and linked genetic markers identified. However linkages of markers with Ms were detected using F2 or BC1 families at maximum linkage disequilibrium and, for many markers, their efficacy to predict genotypes at Ms in onion populations at or near linkage equilibrium remains unknown. In this research, near isogenic lines homozygous dominant and recessive at Ms were developed and screened for 932 single nucleotide polymorphisms (SNPs). Three SNPs tightly linked on chromosome 2 remained in linkage disequilibrium with genotypes at Ms among randomly selected plants from three open-pollinated populations of onion, as well as among inbred lines . These SNPs should be useful for selection of the recessive ms allele to aid in the development of maintainer lines for hybrid production.