Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2001
Publication Date: N/A
Interpretive Summary: The use of a single cytoplasm male-sterile (cms) cmsPET1 cytoplasm and the Rf1 fertility restoration gene for hybrid sunflower production since the early 1970s makes the crop genetically vulnerable. One reason for not having other cms-fertility restoration systems is the inability to find stable and complete cms sources and corresponding strong fertility restoration genes. Of the over 60 cms sources reported, only 17 have been examined in inheritance studies. This report characterizes cms and fertility restoration from two wild H. annuus, six induced mutants, one Native American cultivar, and one H. pauciflorus (rigidus), all of which are suitable for sunflower hybrid breeding use.
Technical Abstract: Male-sterile plants were observed in two accessions of H. annuus, PI413178 and PI413180, in 1987. Fertility restoration genes were identified from PI 413178, P21, and RMAX1 for cmsPI413078, and from PI413180, P21, RHA280 and RPET2 for cmsPI413180. Single dominant genes were responsible for fertility restoration in all lines except RHA280, in which two dominant complementary genes controlled restoration. Twenty-two cms mutants were obtained from mitomycin-C and streptomycin seed treatment of HA89, and six of them from the male-sterile sectors on M1 heads were further examined. More recently, a Native American line, PI432513, also possessed male- sterile cytoplasm. Male fertility of the six cms mutants and cms PI432513 were completely restored by six USDA restoration lines RHA265, RHA266, RHA274, RHA294, RHA296, and RHA801, as well as, by restoration genes in PI432513, Armavir, VNIIMK, and P21. Inheritance studies indicated restoration was controlled by a single dominant gene at the Rf1 locus. Seed of a H. pauciflorus (rigidus) cms source, cmsRIGX, in a cultivated background was obtained through a scientific exchange with USSR scientists in 1987. Restoration genes were identified in Luch and RCMG1 for the cmsRIGX, and the inheritance study suggested 2-complementary-gene control of fertility restoration. All the cms sources were typical male-sterile; without extruding anthers and no pollen production. The cms lines produced no seeds under self-pollination, indicating complete male sterility. Observation of pollen stainability or seed set of hybrids with fertility restoration genes indicated satisfactory fertility restoration. All cms lines in an HA89 background, and germplasm populations containing fertility restoration genes will be made available in spring 2001.