RAPD analysis of 30 American hickory varieties introduced from America was carried out with leaf as material, using improved CTAB method and 16 Operpon. The result showed that the distinct differences of gene type among varieties exist, the ratio of which is up to 78.1%; the marker gene of each variety was identified based on RAPD strip, therefore, the American hickory clones can be identified on the DNA level; the result of system cluster using marker gene is mainly ...