Submitted to: Onion Research National Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 25, 2000
Publication Date: N/A
Technical Abstract: The primary source (S cytoplasm) of cytoplasmic-genic male sterility (CMS) used to produce hybrid-onion Allium cepa) seed traces back to a single plant identified in 1925 in Davis, CA. Many open-pollinated populations also possess this cytoplasm, creating an undesirable state of cytoplasmic uniformity. Transfer of cytoplasms from related species into cultivated populations may produce new sources of CMS. In an attempt to diversify the cytoplasms conditioning male sterility, the cytoplasm of Allium galanthum was backcrossed for seven generations to bulb-onion populations. The flowers of galanthum-cytoplasmic populations possess filaments with no anthers and upwardly curved perianth, making identification of male-sterile plants easier than for either S- or T-cytoplasmic male-sterile onion plants. Mean seed yield per bulb of the galanthum-cytoplasmic populations was measured using flies as pollinators and was not significantly different from that of one of two S-cytoplasmic male-sterile F1 lines, a T-cytoplasmic male-sterile inbred line, or N-cytoplasmic male-fertile lines. Male sterile lines possessing S and galanthum cytoplasms were crossed with populations known to be homozygous dominant and recessive at the nuclear locus conditioning male-fertility restoration of S cytoplasm and progenies scored for male-fertility restoration. Nuclear restorers of S cytoplasm did not condition male fertility for the galanthum-cytoplasmic populations. It is intended that these galanthum-cytoplasmic onion populations be used as an alternative male-sterile cytoplasm for the commercial production of hybrid-onion seed.