ARS | Publication request: Genetic mapping of loci affecting bulb and seed colors in onion

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2006
Publication Date: January 13, 2007
Citation: Khar, A., Jakse, J., Havey, M.J. 2007. Genetic mapping of loci affecting bulb and seed colors in onion [abstract]. Plant and Animal Genome Conference. Available: www.intl.pag.org

Technical Abstract: Bulb color in onion (Allium cepa L.) is conditioned by the interaction of five major loci. White bulbs are conditioned by a dominant allele at the I locus or recessive alleles at the C locus. Colored bulbs (pink, red, yellow, or chartreuse) require the homozygous recessive genotype at the I locus and a dominant allele at the C locus. Pink to red bulbs are produced when both the L and R loci carry dominant alleles. If either the L or R locus is homozygous recessive, yellow bulbs are produced. The seed coat in onion is maternal tissue and black versus brown color is controlled by dominant and recessive alleles, respectively, at the B locus. We developed families segregating for dominant white (I-), recessive white (cc), yellow, and red bulb colors, as well as black versus brown seeds. We scored segregations for simple sequence repeats, bulb colors, and at candidate genes and were able to place C, R, L, and B on the genetic map of onion. Single nucleotide polymorphisms (SNPs) in dihydroflavonol 4-reductase (DFR) co-segregated with one of the loci conditioning red bulb color.