FLOW CYTOMETRIC ANALYSIS OF ACTINIDIA SPECIES

Nuclei were extracted from shoot apices of Actinidia species, treated with ribonuclease, stained with propidium iodide, and then analysed by flow cytometry. Nuclei from shoots and from callus of in vitro cultur es were also analysed. Diploid. tetraploid, hexaploid species, and hyb rids between diploid and hexaploid could be accurately identified. No mixoploidy or aneuploidy was found in shoots from potted plants or fro m shoots of tissue-cultured plants following repeated subculturing. Ho wever, two cytotypes (DNA dodecaploid) of A. deliciosa were identified in plant populations derived by adventitious organogenesis from callu s. The cytotypes were stable over a 2 year period. The nuclear DNA con tent of Actinidia species was determined by co-chopping shoot apices w ith Hordeum, Vigna, and Zea standards. Nuclear DNA contents were 1.53, 3.09, and 4.43 pg DNA per 2 C nucleus for A. chinensis var. chinensis , A. arguta var. arguta, and A. deliciosa var. deliciosa, respectively .