ARS | Publication request: MARKER-FACILITATED SELECTION OF MAINTAINER LINES IN ONION (ALLIUM CEPA L.)

Submitted to: Plant Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 12, 2000
Publication Date: N/A

Technical Abstract: Hybrid-onion seed is produced using systems of cytoplasmic-genic male sterility (CMS). The most widely used source of CMS in onion is conditioned by the interaction of sterile (S) cytoplasm and the homozygous recessive (msms) genotype at a single nuclear male-fertility restoration locus (Ms). Maintainer lines used to seed propagate male sterile lines possess normal fertile (N) cytoplasm and the homozyous recessive (msms) genotype at the Ms locus. Conventionally, it take four to eight years to establish if maintainer lines can be extracted from an uncharacterized population or segregating family. We previously reported development of a PCR marker that distinguishs N and S cytoplasms of onion. To tag the nuclear male-fertility restoration locus (Ms), we evaluated segregation at Ms over at least three environments. Segregations of AFLPs, RAPDs, and RFLPs revealed molecular markers flanking the Ms locus. We are working to convert these linked molecular markers to nonradioactive PCR based detection. We evaluated the flanking molecular markers among S1 families randomly selected from open-pollinated (OP) populations and commercial inbred families and determined the number of testcrosses required to identify maintaining genotypes.