GENETIC DIVERSITY ANALYSIS BY RAPD IN CATHAYA ARGYROPHYLLA CHUN ET KUANG

Genetic diversity level of Cathaya argyrophylla was confirmed by rando m amplified polymorphic DNA (RAPD) markers. Seventy five samples (indi viduals), collected from Hunan and Sichuan provinces of China were use d in the study. 21 10-mer oligonucleotide primers detected 106 sites, and 34 (32%) of them were polymorphic. The level of genetic variation in C. argyrophylla was lower than those of other conifers, and was con sidered to be associated with the complexity of habitats. The percenta ges of polymorphic sites (PPS) in the Hunan and Sichuan populations we re 18 % and 25 % respectively. 7.99 % of genetic variation existed bet ween the two populations; this value was higher than the mean value (6 .8 %) among populations in conifers displayed by allozyme. Some subpop ulations of C. argyrophylla were greatly differentiated because of sit e mutation and genetic drift. The highest value of genetic difference between subpopulations amounted to 16.23 %. In addition, a concept of diversity coefficient (DC), a value used to measure the genetic divers ity level, and its calculation were proposed. The low genetic diversit y level of C. argyrophylla was thought to be one of the factors causin g its endangered status.