ALLOZYME VARIATION IN 4 POPULATIONS OF TAIWANIA-CRYPTOMERIOIDES IN TAIWAN

Genetic diversity within and genetic differentiation among 4 populatio ns of Taiwania (Taiwania cryptomerioides HAY.) in Taiwan were investig ated using 327 offspring growing in a 10-year-old provenance/progeny t est plantation. Eight of the 15 loci examined were polymorphic. The av erage proportion of polymorphic loci per population was 50.2% (99% cri terion for polymorphism). Mean expected heterozygosity was 0.145, rang ing from 0.126 to 0.173 in the different populations. On average, the percent heterozygous loci/individual ranged from 12.3 to 19.4, the num ber of alleles/locus from 1.53 to 1.67, and the effective number of al leles/locus from 1.16 to 1.26. The slightly lower number of alleles/lo cus compared to other coniferous species probobly reflects the insular nature of Taiwania's distribution. Partitioning the genetic variabili ty into within- and among-population components with F-statistics led to an estimate of within-population variation amounting to 94.7% of to tal variation. This suggests a lack of barriers to gene flow among pop ulations. Geographic distance and NEI'S genetic distance appear to be positively related, except the Ta-Jiann population differs from the ot hers in terms of genetic distance to a greater degree than they do amo ng themselves. This may result from topographic isolation of the Ta-Ji ann population.