FLOW CYTOMETRIC ANALYSIS OF GENOME SIZE VARIATION IN CULTIVATED AND WILD PISUM-SATIVUM (FABACEAE)

Fifteen cultivars, landraces, and wild accessions of Pisum sativum sub species, and one accession of P. abyssinicum were analysed with flow c ytometry (DAPI staining) using P. sativum 'Kleine Rheinlanderin' as in ternal standard. Applying the method of jointly isolating, staining, a nd measuring nuclei of individual seedlings of test and standard mater ial, it was found that in all P. sativum comparisons G 1 and G 2 peaks were invariably unimodal and symmetric at coefficients of variation m ostly less than 2%. This is strong evidence for absence of significant genome size variation in the P. sativum strains analysed. These data are markedly at variance to results of other authors reporting conside rable genome size variation within P. sativum. However, in P. abyssini cum flow cytograms and Feulgen densitometric measurements indicate 4-8 % more DNA, at same chromosome number (2n = 14), than in P. sativum. T his result demonstrates that genome size variation is indeed existent in the genus and requires further examination.