Nuclear and cytoplasmic interactions for petaloid male-sterile accessions of wild carrot (Daucus carota L.)

Abstract

Male-sterile carrot plants with petaloid-stamens were discovered in wild populations in the vicinity of Guelph, Ontario, Canada and inheritance of phenotype was assessed. Genetic analyses were also conducted to identify nuclear restorer genes of petaloid cytoplasmic male sterility (CMS) from wild carrot, and determine if Guelph, Cornell and Wisconsin cytoplasmic male-sterile accessions interacted similarly with alleles of restorer genes from different sources. Petaloid male-sterility was inherited cytoplasmically for the new Guelph accessions, and nuclear genotypes which normally produce 'green' or 'white' petaloid-stamens in combination with the Cornell cytoplasm also produced corresponding phenotypes when backcrossed to Guelph cytoplasmic accessions. Two duplicate restorer genes were identified from wild carrot. Dominant alleles of single restorer genes from three sources, one from wild carrot and two from cultivated germplasm, restored stamen production to Guelph, Cornell and Wisconsin petaloid cytoplasmic accessions, suggesting that the cytoplasms were genetically identical.