Efficacy of molecular markers jnurf13 and AcPms1 for prediction of genotypes at the nuclear Ms locus in North American open-pollinated populations of onion

Authors: Havey, Michael; VON KOHN, CHRISTOPHER - University Of Wisconsin

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2017
Publication Date: 8/15/2017
Citation: Havey, M.J., Von Kohn, C. 2017. Efficacy of molecular markers jnurf13 and AcPms1 for prediction of genotypes at the nuclear Ms locus in North American open-pollinated populations of onion. HortScience. 52(8):1052–1053. https://doi.org/10.21273/HORTSCI11954-17.
DOI: https://doi.org/10.21273/HORTSCI11954-17

Interpretive Summary: Seed of hybrid onion (Allium cepa L.) is produced using cytoplasmic male sterility (CMS). Male sterility is conditioned by the interaction of male-sterile (S) cytoplasm and the homozygous recessive genotype at the nuclear male-fertility locus Ms. Due to the biennial generation time of onion, classical crossing and segregation analyses take years to establish cytoplasms and genotypes at Ms. Two nuclear markers (jnurf13 and AcPms1) have been reported to cosegregate with Ms and correctly predict genotypes in commercial breeding lines and diverse onion germplasm; however these markers were less predictive for open-pollinated (OP) populations from India. We evaluated the efficacy of jnurf13 and AcPms1 to correctly classify genotypes at Ms using 144 random plants from three OP populations of North American onion. No recombination events were detected between AcPms1 and the Ms locus and three events had occurred between jnurf13 and AcPms1/Ms. Our results support either marker as a useful tool to predict genotypes at Ms in North American populations of onion, with AcPms1 being the better of the two. These results will be of use for onion breeders in the public and private sectors to more efficiently develop male-sterile inbreds for the production of new onion hybrids.

Technical Abstract: Seed of hybrid onion (Allium cepa L.) is produced using cytoplasmic male sterility (CMS) and the for most widely used source of onion CMS, male sterility is conditioned by the interaction of male-sterile (S) cytoplasm and the homozygous recessive genotype at the nuclear male-fertility locus Ms. Due to the biennial generation time of onion, classical crossing and segregation analyses take years to establish cytoplasms and genotypes at Ms. Numerous molecular markers have been developed to distinguish onion cytoplasms and estimate genotypes at Ms. Two nuclear markers (jnurf13 and AcPms1) have been reported to cosegregate with Ms and correctly predict genotypes in commercial breeding lines and diverse onion germplasm; however these markers were less predictive for open-pollinated (OP) populations from India. We evaluated the efficacy of jnurf13 and AcPms1 to correctly classify genotypes at Ms using 144 random plants from three OP populations of North American onion. No recombination events were detected between AcPms1 and the Ms locus and three events had occurred between jnurf13 and AcPms1/Ms. Our results support either marker as a useful tool to predict genotypes at Ms in North American populations of onion, with AcPms1 being the better of the two.