Flow cytometric investigations on <em>Pelargonium</em> × <em>crispum</em>: an estimation of nuclear DNA contents with two different internal standards

Abstract

Seven Pelargonium × crispum cultivars, four breeding clones and the species P. crispum were analysed by flow cytometry. Tomato ‘Stupické’ (2C value = 1.96 pg) and cauliflower ‘Korso’ (2C value = 1.31 pg) were used as inter­nal standards to estimate the DNA content of the samples. As expected, the 2C values of the investigated diploid and tetraploid genotypes discriminated significantly. Overall, the mean 2C values ranged from 0.97 to 2.18 pg DNA and formed three significantly different groups. The estimation of the DNA content of the cultivars and breeding clones was independent of the standard used with one exception; for P. crispum the estim­ated DNA contents differed significantly. The standards ‘Stupické’ and ‘Korso’ are equally appropriate for flow cyto­metric investigation of genotypes with 2C values < 1.8 pg like diploid genotypes of the section Pelargonium. Tomato ‘Stupické’ is a rather impractical standard for geno­types with 2C values of about 2 pg, due to the overlapping positions of the 2C values of sample and standard.