Sample size for number of RAPD markers to estimate genetic diversity in Eucalyptus

Abstract

A total of 501 RAPD markers were generated for a population consisting of 84 Eucalyptus genotypes, 89.8% of which were polymorphic and 10.2% monomorphic. Coherent genotype clustering based on the estimated genetic distances was observed for the species. Bootstrap analyses based on the number of RAPD markers revealed that 393 or more markers achieved values below 5% for stress, lower than 5 for sum of squares, and higher than 95% for correlation statistics. The estimated diversity based on the Shannon index amounted to about 95-96% for E. urophylla and 85-88% for E. grandis. In an 84-genotype population, each species presented significant differences for the estimated genetic distances. On the other hand, when the sample was reduced to 10 genotypes, the difference was no longer detected by the t-test at 1% probability.