Comparison of Experimental Designs for Clonal Forestry Using Simulated Data
Authors: Gezan, Salvador A.1; White, Timothy L.1; Huber, Dudley A.1
Source: Forest Science, Volume 52, Number 1, January 2006 , pp. 108-116(9)
Abstract:
Various alternatives for the design of clonal field trials in forestry were studied using simulated data to identify “optimal” or “near-optimal” scenarios for the estimation of genetic parameters. The simulated field site consisted of a rectangular grid on which 256 clones with 8 ramets each were installed. Estimates of genetic parameters were compared for (1) single-tree and four-tree row plots; (2) several experimental designs (completely randomized, randomized complete block, incomplete blocks of various sizes, and row–column); (3) no mortality versus 257% mortality; and (4) different patterns of environmental variability (only patches, only gradients, and both patches and gradients). Use of single-tree plots, on average, increased the correlations between true and predicted clonal values by 57% over four-tree row plots and increased genetic gain from selection. Starting with a parametric broad-sense heritability (H B 2) of 0.25 for a completely randomized design, the experimental designs resulting in the highest H B 2 were row–column designs for single-tree plots and incomplete blocks with 32 blocks per replication when four-tree row plots were used. These designs increased average heritability 107% and 147% over a randomized complete block design, respectively. The only effect of 257% mortality was an increase in the variability of some variance component estimates.Keywords: Mixed models; REML; field testing; environmental variability; heritability
Document Type: Research article
Affiliations: 1: Salvador A. Gezan, School of Forest Resources and Conservation, University of Florida, PO Box 110410, Gainesville, FL 32611—Phone: (352) 846-0894;, Fax: (352) 846-1277, Email: sgezan@ufl.edu.
