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United States Department of Agriculture

Agricultural Research Service

Title: Allelic Relationships among Newly Identified Fertility Restoration Genes for the Cms Pet1 Cytoplasm

Authors
item Seiler, Gerald
item Jan, Chao-Chien

Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2001
Publication Date: N/A

Interpretive Summary: Cultivated hybrid sunflower is the second largest hybrid crop in the world. It has a very narrow genetic base because it depends on a single cytoplasm and a limited number of male pollinators. This narrows the genetic base putting the crop in a potentially dangerous position in terms of genetic vulnerability. The wild sunflower species have served as a source of new male pollinators for hybrid sunflower. It was not known whether the genes of the male pollinators of the wild species are different from the commonly used male gene. The objective of the present study was to determine the genetic relationships among the commonly used male gene and the genes of eight populations derived from wild species. Progenies of the cross combinations among the nine parents did not segregate for male fertility. Non-segregation indicates that the fertility genes of the wild species are at the same location on the chromosome as the commonly used male gene. While the male fertility genes from the eight wild sunflower populations may be located at the same location as the commonly used male gene, it is possible that they are different in their mode of action. This relationship needs to be studied further.

Technical Abstract: Cultivated hybrid sunflower production depends on a single male-sterile cytoplasm (French PET1) and a few fertility restoration genes. This narrows the genetic base putting the crop in a potentially dangerous position in terms of genetic vulnerability. The wild species have served as a source for new fertility restoration genes for the PET1 cytoplasm. It was not known whether the fertility restoration genes from the wild species for the PET1 cytoplasm were different from the commonly used Rf1 gene. The objective of the present study was to determine the genetic relationships among the Rf1 gene and the restoration genes of eight fertility restoration populations derived from wild species. F1's from the half-diallel cross combinations among the nine parents were testcrossed onto cms HA89. Testcross progenies of crosses of RHA 274 with other lines did not segregate for fertility restoration, except for crosses with Rf ANN-1742 and Rf ANN-1064. Non-segregation indicates that the restoration genes are at the same locus as the commonly used Rf1 gene in RHA 274. It is therefore likely that the restoration gene(s) of these lines are at the same locus as the Rf1 gene, and that a few plants in some populations were not homozygous for fertility restoration, as originally hypothesized. The restoration genes from the eight wild sunflower accessions are likely to be alleles of the Rf1 gene. Further studies to compare them with the Rf1 gene are needed.

Last Modified: 4/15/2014
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