ARS | Publication request: MARKER-FACILITATED SELECTION OF MAINTAINER LINES IN ONION

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 8, 2002
Publication Date: December 15, 2002
Citation: Havey, M.J., Gokce, A. 2002. Marker-facilitated selection of maintainer lines in onion. Meeting Abstract.

Technical Abstract: Cytoplasmic-genic male sterility (CMS) is used to produce hybrid-onion (Allium cepa L.) seed. For the most widely used source of onion CMS, male sterility is conditioned by the interaction of the male-sterile (S) cytoplasm and the homozygous recessive genotype at a nuclear male-fertility restoration locus (Ms). Maintainer lines are used to seed propagate male-sterile lines, possess normal (N) male-fertile cytoplasm, and are homozyous recessive at the Ms locus. Identification of nuclear markers tightly linked to the Ms locus would allow for molecular-facilitated selection of maintainer lines. We evaluated testcross progenies from a segregating family and randomly selected plants from three open-pollinated populations for nuclear restoration of male fertility over at least three years. Because the proportion of male-sterile testcross progenies showed significant (P<0.01) year effects, it is imperative to score male-fertility restoration over environments. Too many male-sterile testcross progenies were often observed, indicating that the dominant allele conditioning fertility restoration for S cytoplasm may not show complete penetrance. Segregations of amplified fragment length polymorphisms (AFLPs), randomly amplified DNAs (RAPDs), and restriction fragment length polymorphisms (RFLPs) revealed RFLPs flanking the Ms locus at 0.9 and 8.6 cM. The RFLPs and Ms were at linkage equilibrium in the three open-pollinated onion populations. Single nucleotide polymorphisms (SNPs) were identified within the genomic sequence of AOB272, which reveals the RFLP closest to the Ms locus, and can be used for marker-facilitated selection of maintainer lines.