Genome sizes of 227 accessions of Gagea (Liliaceae) discriminate between the species from the Netherlands and reveal new ploidies in Gagea

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Table 2 Summary of genome sizes in pg (2C), number of accessions and inferred chromosome numbers of species of Dutch and German gageas

Species	Average pg/2C	Inferred ploidy	Chromosome number	Number of accessions
Gagea minima (L.) Ker Gawl.	14.9	Diploid	2x = 24	2
Gagea villosa (M.Bieb.) Sweet	17.0	Diploid	2x = 24	14
Gagea villosa (M.Bieb.) Sweet	32.3	Tetraploid	4x = 48	6
Gagea lutea (L.) Ker Gawl.	42.7	Hexaploid	6x = 72	22
Gagea lutea var. glauca L.Klein	42.3	Hexaploid	6x = 72	16
Gagea spathacea (Hayne) Salisb.	46.7	Nonaploid	9x = 108	17
Gagea pratensis (Pers.) Dumet.	32.8	Tetraploid	4x = 48	30
Gagea pratensis (Pers.) Dumet.	39.9	Pentaploid	5x = 60	85
Gagea pratensis (Pers.) Dumet.	45.6	Hexaploid	6x = 72	20
Gagea pratensis (Pers.) Dumet.	75.8	Decaploid	10x = 120	2
G. × pomeranica R.Ruthe	34.9	Hexaploid	5x = 60	11
G. × megapolitana Henker	46.8	Hexaploid	6x = 72	2

The term ‘inferred ploidy’ indicates that the ploidy is derived from the genome size and not based on chromosome counts. It is preferred to the proposed term ‘DNA ploidy’ (Suda et al. 2006) as this seems more ambiguous. Inferred decaploidy is found for the first time in G. pratensis. The hybrid G. × megapolitana, is only collected in Germany so far. The largest genome contains roughly 60 × 10⁹ more base pairs than the smallest. A difference of 1 pg amounts to a difference of nearly 1 × 10⁹ base pairs, so far exceeds a single taxonomic character.