DNA contents of oil palm (Elaeis guineensis Jacq.) cultivars were analyzed by flow cytometry using different external reference plant species. Analysis using corn (Zea mays line CE-777) as a reference plant gave the highest DNA content of oil palm (4.72±0.23 pg 2C-1) whereas the DNA content was found to be lower when using soybean (Glycine max cv. Polanka) (3.77±0.09 pg 2C-1) or tomato (Lycopersicon esculentum cv. Stupicke) (4.25±0.09 pg 2C-1) as a reference. The nuclear DNA contents of Dura (D109), Pisifera (P168) and Tenera (T38) cultivars were 3.46±0.04, 3.24±0.03 and 3.76±0.04 pg 2C-1 nuclei, respectively, using soybean as a reference. One haploid genome of oil palm therefore ranged from 1.56 to 1.81±109 base pairs. DNA contents from one-year-old calli and cell suspension of oil palm were found to be significantly different from those of seedlings. It thus should be noted that genomic DNA alteration occurred in these cultured tissues. We therefore confirm that flow cytometric analysis could verify cultivars, DNA content and genomic DNA alteration of oil palm using soybean as an external reference standard.
