Flow cytometric classification of oil palm cultivars
Efficiencie in each nuclear lysis buffer on flow cytometric analysis (FCM) of oil palm were compared for cultivar classification. Embryos and unopened leaves of one to twelve months-old seedlings were used as initial materials with five nuclear lysis buffers, including LB01, WPB, Otto’s, Tris.MgCl2 and Galbraith. Although these buffers showed distinct peaks of propidium idodide (PI) fluorescence for oil palm embryos, the buffers differed considerably in fluorescence intensity (FL), coefficient of variance (%CV), debris factor (%DF) and yield factor (YF) values when analyzed with their seedlings. The results show that LB01 was the most suitable buffer (lowest %CV and high FL value) for oil palm embryos resulting in 3.7 pg of 2C-DNA. For all the seedlings, only WPB gave the highest value of FL and lowest value of %CV resulting approximately in 3.8 pg of 2C-DNA, whereas the highest value of YF and lowest value of %DF were mostly found in LB01. Of interest is the fact that only WPB showed consistency position of PI fluorescence histograms when analyzed with all seedlings. WPB was therefore used to classify the cultivars of hybrid Tenera and its parents (Dura and Pisifera) by means of DNA contents. DNA contents of Dura and Pisifera ranged from 6.3 to 7.6 and 5.3 to 6.1 pg and their genome size (1C DNA contents) is therefore greater than 3,000 and 2,000 Mbp, respectively. The results confirmed that Dura, Pisifera and Tenera cultivars could be classified using FCM-derived DNA contents.
Key words: 2C-DNA value, cultivars, flow cytometry, nuclear lysis buffers, oil palm.