ARS | Publication request: Genomes of Diploid Bromus Erectus and Bromus Viriagatus

Submitted to: Asa-Cssa-Sssa Annual Meeting Abstracts
Publication Acceptance Date: August 10, 2004
Publication Date: October 1, 2004
Citation: Tuna, M., Vogel, K.P., Armuganathan, K. 2004. Genomes Of Diploid Bromus Erectus And Bromus Viriagatus. Annual Meeting. Agronomy Abstracts. Cd-Rom No. 4182. Asa, Cssa, Sssa. Madison, Wi.

Technical Abstract: Diploid B. erectus and B. variagatus are Eurasion bromegrasses that has been placed in the Pnigma section of genus Bromus. The objective of this study was to characterize the genomes of the diploid B. erectus and B. variagatus by cytogenetic methods and compare them to the genomes of the other species included in the section Pnigma. Genome size was determined by flow cytometry using propidium iodide staining. Genome size for diploid B. erectus and B. variagatus were 6.19 and 6.76 pg, respectively. C-banding procedure were used to identify individual mitotic chromosomes and to develop a karyotype for both B. variagatus and B. erectus. C-bands were located mainly at telomeric regions in both species, as all the chromosomes had telomeric C-bands. However, the intensity of the bands was different between the two species. It wasn't possible to identify all homologous chromosomes by chromosome morphology and C-banding patterns due to excessive similarity of chromosomes although the species were diploid. Results of flow cytometric study indicate that speciation at the diploid level in species of Bromus section Pnigma has not produced great differences in size of basic genome and therefore, both of the two diploid accessions could be possible progenitors of the polyploidy species of section Pnigma such as smooth bromegrass, B. inermis. However, the C-banded karyotypes of the species differ from the genomes of the polyploid species of the genus. The polyploidy genomes may have changed during their evolution.