Author
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Havey, Michael |
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KHRUSTALEVA, LIUDMILA - Moscow State University |
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Submitted to: National Allium Research Conference
Publication Type: Abstract Only Publication Acceptance Date: 11/5/2014 Publication Date: 12/6/2014 Citation: Havey, M.J., Khrustaleva, L.I. 2014. Why are there so many molecular markers tagging the Ms locus of onion [abstract]. National Allium Research Conference. Paper No. 4. Interpretive Summary: Technical Abstract: The primary source of male sterility used to produce hybrid-onion cultivars is conditioned by the interaction of the cytoplasm (N versus S) and alleles at one nuclear male-fertility restoration (Ms) locus Due to the biennial life cycle of onion and the necessity to score testcross progenies, the determination of genotypes at Ms is expensive and time consuming. The Ms locus maps to chromosome 2 of onion and linked genetic markers have been identified by numerous research groups. However it is not clear why so many researchers have enjoyed success in tagging the Ms locus, often after evaluating relatively few polymorphisms. We used Tyramide-FISH to identify the physical location of molecular markers tightly linked to Ms, and demonstrate these markers are located near the centromere of chromosome 2. Recombination occurs rarely in the centromeric regions of onion chromosomes, and therefore tightly linked markers may be physically quite distant from Ms. Using DNAs from plants from open-pollinated populations genotyped at Ms, we estimated the most likely linkage arrangement of molecular markers closely associated with Ms. These markers should be useful for selection of the recessive Ms allele to aid in the development of maintainer lines for hybrid-onion development. |
