Determination of nuclear DNA content and ploidy of some Bromus L. germplasm by flow cytometery

摘要

The objective of this study was to determine nuclear DNA content and ploidy of 48 Bromus L. gene bank accessions obtained from USDA by flow cytometry. Based on the results of the flow cytometric analysis, the mean 2C nuclear DNA content of Bromus accessions used in the study varied between 11.43 pg with 26.62 pg. The nuclear DNA content differences among Bromus L. accessions were statistically significant at P 0.01 level. The accessions were easily separated into three distinct groups according to their DNA contents. The mean 2C nuclear DNA content of the groups were 11.82, 22.43 and 26.17 pg (min. and max. values of group were between 11.43–12.65 pg, 21.45–22.77 pg, 25.48–26.62 pg, respectively). Nuclear DNA content of the accessions were correlated with their ploidy levels by counting chromosomes of the one plant from each group with classical staining methods. In conclusion, majority of the Bromus accessions (33 out of 48) analysed in the study were tetraploid with 2n=4x=28 chromosomes. Ten and five of the remaining accessions were octaploid (2n=8x=56) and (2n=10x=70) decaploids, respectively. No decaploid B. inermis plant reported until today. However, decaploids were reported for B. riparius and B. biebersteini species. Therefore, decaploid plants determined in this study should be considered as either B. riparius or B. biebersteini.