ABSTRACT
Object To analyze the rDNA ITS sequences between wi ld plants and cultivars of Trapa L. and study the utility in p hylogenesis and identification of these two groups. Methods The ITS gene fragments were PCR amplified and sequenced. The rDNA ITS regions w ere analyzed by means of the software of Clustal and Mega 2.0. Result s The rDNA sequences of 234-236 bp ITS1, 220-221 bp ITS2 gene fragment , and 5.8 S rDNA for 164 bp evenly were obtained from ten populations of Trapa L. The intraspecific substitution varies from 0.22% to 2. 94%. The variable sites are 16 while informative sites are six. The phylogenet ic tree based on ITS data was set up by NJ method. Conclusion ITS sequence is a pretty good molecular marker which can identify wild plants of Trapa L. from their cultivars. Diversity of ITS in differen t populations is less at intraspecific level. It is infered that the plants of Trapa L. may be derived from the same population of one species .