Genome size in Chinese soybean accessions - Stable or variable?

Abstract

Variation in genome size up to 1.12-fold has been recently reported in 90 Chinese accessions of Glycine max (soybean). Generally such results have to be viewed with reservation if rigorous internal standardization and control tests for the repeatability of the results have not been done. Therefore, we reinvestigated ten accessions (five allegedly ranking high and five low) for genome size using propidium iodide flow cytometry and Feulgen densitometry. Using flow cytometry, the maximum difference between accessions was 1.018-fold (non-significant); the difference between the means of the high-ranking and low-ranking group was 1.002-fold (non-significant). With Feulgen densitometry, the maximum difference between accessions was 1.034-fold (non-significant). The present data suggest genome size constancy, in terms of cytometric evidence, for the Chinese soybean accessions in question. Likewise, no reasonable evidence was obtained for a difference between Chinese and American soybeans.