The effect of pedigree error by misidentification of individual trees on genetic evaluation of a full-sib experiment

A simulation based on real data shows how increasing rates of individual tr ee misidentification result in increasing underestimation of additive genet ic variance and narrow-sense heritability as well as increasing overestimat ion of the dominance variance. The data used came from a Pinus sylvestris L . progeny trial with 202 full-sib families from 52 unrelated parents at abo ut one-third of the rotation. When 1% of 4970 individual trees were misiden tified, the estimates of additive variance and heritability decreased by an order of magnitude that corresponded to the standard errors. The estimate of dominance variance approached that of additive variance when the error r ate increased to 2%, after which further misidentification made the estimat es diverge beyond the expected parameter space of the genetic model. The er ror effect was less pronounced when selecting the best parents using approx imate best linear unbiased predictors, but their predicted performance was increasingly underestimated as the error rate increased.