New Fertility Restoration Genes from Wild Sunflowers for Sunflower PET1 Male-Sterile Cytoplasm
1994
Seiler, Gerald J. | Jan, C. C.
Cultivated hybrid sunflower (Helianthus annuus L.) production depends on a single male-sterile cytoplasm, PET1, derived from H. petiolaris Nutt. and a few fertility restoration genes. This study was conducted to locate new restoration genes for the PET1 cytoplasm from the wild species of the genus Helianthus. Ten wild species populations from the USA were grown in a field nursery and crossed with cytoplasmic male-sterile inbred line cmsHA 89 to determine the presence and inheritance of restoration genes in wild annual and perennial species. Standard sunflower breeding techniques were used to obtain F₁ and B₁CF₁ seed, whereas F₂ seed was produced by sibbing F₁ plants instead of selfing due to the low self-compatibility. All H. annuus L., H. argophyllus T. & G., H. praecox ssp. runyonii Heiser, and H. tuberosus L. populations possessed dominant fertility restoration genes at high frequencies, varying from 57 to 100%. Segregation ratios of male-fertile to male-sterile plants in the BC₁ (1:1) and F₂ (3:1) generations of nine crosses suggested a single dominant gene for fertility restoration. Other segregation ratios suggested that three genes were involved in one cross of H. argophyllus and that fertility was restored when at least two dominant alleles were present at any of the three loci. The new sources of fertility restoration genes from wild sunflowers will be valuable for sunflower breeding and selection programs by providing additional genetic diversity.
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