Genome size variation and C-band polymorphism in Alstroemeria aurea, A-ligtu and A-magnifica (Alstroemeriaceae)

Among a total of 43 accessions of Alstroemeria aurea, A. ligtu and A. magnifica nuclear DNA amounts (2C-values) showed significant intraspecific variation, 1.09, 1.21 and 1.15 fold, respectively, when determined through flow cytometric measurements of fluorescence of propidium iodide (PI) stained nuclei. After staining with another fluorochrome, 4',6-diamidino-2-phenylindole (DAPI), an intraspecific variation of 1.10, 1.11 and 1.12 fold, respectively, was found. C-band polymorphisms were present among and within the accessions of all three species. In some cases only very small differences in C-banding pattern were observed. In other cases, however, differences were more prominent. Besides C-band polymorphism, there were also instances of chromosome length polymorphism, which concerned the total chromosome complement or single chromosomes. The variation in nuclear DNA amount in A. aurea and A. ligtu was more or less continuous, except for one accession of A. ligtu subsp. simsii. Artificial selection and possibly introgression of chromosomes from other species may have moulded the karyotypes of some of the accessions of A. aurea, a species that has been under cultivation for more than 160 years. The variation as observed in A. magnifica subsp. magnifica was discontinuous and could be due to a broad species concept.