Nuclear genome size analysis in Krascheninnikovia ceratoides s. l. (Amaranthaceae)

The total nuclear DNA amount (2C value) of 75 individuals of Krascheninnikovia ceratoides s. l. was assessed by flow cytometry in 16 populations. The mean 2C value in all samples ranged from 2.59 to 6.99 pg. The relationship between total 2C values and ploidy level was calibrated using chromosome counting in four populations. Diploids (2n = 18) and tetraploids (2n = 36) were revealed. In diploid plants, mean 2C value varied between 2.59 to 3.72 pg, in tetraploids − from 6.04 to 6.99 pg. The GS of diploids is approximately half the GS of tetraploids. Diploids were observed in seven populations from the Orenburg Region and the Republic of Tyva (Russia), Kyzylorda and Almaty Regions (Kazakhstan). Tetraploids were recorded in eight populations from Kazakhstan, Orenburg and Novosibirsk Regions, from the Republics of Altai and Sakha (Yakutia). One mixed population was found in the Republic of Khakassia represented by di- and tetraploids. We did not find any regularity in the geographical distribution of the two cytotypes. The studied plants showed no significant morphological features of taxonomic value, therefore we consider all the samples belong to Krascheninnikovia ceratoides s. str.