This paper was aimed at studying the genetic structure of populations of Cryptocarya moschata and proposing conservation strategies for the species. Allozyme data of 18 polymorphic loci were collected from 214 trees sampled from four natural populations located in two regions of the State of São Paulo, Brazil. Estimates of Wright's F statistics were computed on the basis of observed and expected heterozygosities. The analysis of variance, pooled over loci and alleles, was also used to compare corresponding estimates of F (= FIT), <FONT FACE="Symbol">q</font>P (= FST) and f (= FIS). Both methods provided similar results with <img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)">IT = 0.142, <img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)">ST = 0.140, <img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)">IS = 0.002 and <img src="http:/img/fbpe/rbb/v22s2/f.gif" alt="f.gif (76 bytes)">= 0.116, <img src="http:/img/fbpe/rbb/v22s2/a3form05.gif" alt="a3form05.gif (151 bytes)">P = 0.123 and <img src="http:/img/fbpe/rbb/v22s2/a3form06.gif" alt="a3form06.gif (144 bytes)">= 0.008. Results indicated that individuals within populations are probably panmitic. Diversity among populations was very high, similar to what would be expected for groups of plants with a half-sib family structure. Estimates of <img src="http:/img/fbpe/rbb/v22s2/a3form05.gif" alt="a3form05.gif (151 bytes)">P, obtained for populations taken two at a time, indicated that diversity tended to increase with distance and suggested that isolation by distance is a factor to be considered. An estimated gene flow of 0.9 migrants per generation corroborated to the pronounced divergence found among populations. Due to the negligible <img src="http:/img/fbpe/rbb/v22s2/a3form07.gif" alt="a3form07.gif (245 bytes)">IS value found, the variance effective size for each population is equivalent to its sampling number. In this case, management and conservation strategies aimed at preserving high intrapopulation genetic variation, will imply in the maintenance of large populations. In addition, due to the relatively large divergence detected among populations, the preservation of the species as a whole will also require the maintenance of many such populations.
Genetic structure; effective population size; gene flow; Cryptocarya moschata