Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/25/2008
Publication Date: 6/1/2008
Citation: Feng, J., Jan, C.C. 2008. Identification of a new CMS cytoplasm and localization of its fertility restoration genes in sunflower. Proceedings of 17th International Sunflower Conference, June 8-12, 2008, Cordoba, Spain. p. 583-587. Interpretive Summary: Since the first sunflower CMS was reported in 1969, 72 CMS sources have been identified in the Helianthus genus (Serieys, 2005). So far, the CMS PET1 developed by Leclercq (1969) from Helianthus petiolars Nutt. is the only one that has been extensively used in commercial hybrid sunflower production. Genetic analyses indicated that almost all CMS restoration lines currently used in sunflower breeding carry the same restorer gene Rf1 (Serieys, 1996, 2005). In order to prevent cytoplasmic uniformity and reduce genetic vulnerability, alternative CMS and restorer sources are needed for sunflower breeding programs. The current research was devoted to identification of a new CMS and fertility restoration genes, and also localization of the fertility restoration genes on the sunflower genetic map.
Technical Abstract: Cytoplasm male sterility (CMS) and its fertility restoration genes (Rf) are critical tools for hybrid seed production. To broaden the genetic diversity of sunflower hybrid breeding materials, an initial F2 population of 113 individuals was generated from a single F1 plant from the cross H. giganteus/7*HA 89/3/H. giganteus/ 6* HA 89// H. maximiliani 1631 (amphiploid) and this population was used to develop the genetic model for the new CMS and fertility restoration (Rf) system. The bulked segregant analysis strategy was used to screen for markers polymorphic for the segregation populations. Equal amounts of DNA from 10 male-sterile and 10 male-fertile F2 plants were bulked to form the sterile and fertile pools, respectively. In total, 200 simple sequence repeat (SSR) markers relatively evenly distributed among the 17 linkage groups were selected to screen for polymorphism between male-fertile and male-sterile pools. The polymorphic markers were used to genotype F2 and F2-derived F3 populations. The results showed that a new CMS, designated as CMS GIG2, was identified from an interspecific cross between Helianthus giganteus accession 1934 and H. annuus cv. HA 89. We also identified the fertility restoration gene for CMS GIG2 from an amphiploid involving H. maximiliani accession 1631. The CMS GIG2 and its fertility restoration gene were introduced into HA 89 background through recurrent backcross and single plant selection techniques. Genetic analysis revealed that the CMS GIG2-fertility restoration system is controlled by a completely dominant gene, designated as Rf4, in a HA 89 background. The gene Rf4 was mapped onto linkage group 3 and tightly links with the markers ORS1114 and ORS13, based on 576-plant F2 and F3 populations. The CMS GIG2-Rf4 system tagged by molecular markers provides an alternative genetic source for hybrid sunflower breeding.