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

Submitted to: Onion Research National Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 25, 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 is conditioned by the interaction of sterile (S) cytoplasm and the nuclear homozygous recessive genotype at the nuclear male-fertility restoration locus (Ms). Maintainer lines used to seed propagate male-sterile lines possess normal fertile (N) cytoplasm and the homozyous recessive genotype at the Ms locus. We previously developed a PCR marker useful to distinguish 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 at 1.9 and 7.1 cM. These organellar and nuclear markers are being used to select plants from open-pollinated onion population and determine the reduction in testcrosses required to identify CMS-maintaining genotypes.