ACCURACY OF GENETIC PARAMETERS ESTIMATION AND PREDICTION OF GENOTYPIC VALUES IN EUCALYPTUS USING DIFFERENT PLOT TYPES

Evandro Vagner Tambarussi,Amanda Roberta Vergani,Mateus Chagas Andrade,Matheus Perek,Marcos Rafael Amâncio,João Gabriel Zanon Paludeto,Odair Bison,Andrea Nogueira Dias

doi:10.1590/01047760202026042710

Evandro Vagner Tambarussi, Amanda Roberta Vergani + Show 6 more

Open Access

https://doi.org/10.1590/01047760202026042710

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Abstract

A suitable experimental design should control the environmental effect and be capable of discriminating genotypes. Two clonal tests of Eucalyptus were planted side by side in a randomized block design with the same 32 treatments under two different plot designs. The first trial was designed with five plants per plot (linear plot, LP) and six block replicates at a spacing of 3 x 2 m. The second trial was designed with one plant per plot (single-tree plot, STP) and 30 block replicates also at a spacing of 3 x 2 m. Diameter at breast height (dbh), height (h), and individual volume (vol) were measured at five years of age. The STP design presented broad-sense heritabilities values of 0.23 for h and 0.41 for vol, which were higher than those found for the LP design (0.12 for h and 0.22 for vol). The ratio between the standard error and the estimated genotypic variance (Sg^ ) was lower for the three evaluated traits in the STP trial. The correlations between the genetic values were positive and of high magnitude, ranging from 0.87 (h) to 0.91 (vol), but there were many differences between the two designs with regard to the ranking of clones. The STP presented better discriminant power according to the biplot analysis, as well as more accurate and reliable estimates.

Highlights

Eucalyptus is a very widely planted genus throughout the world
Similar results were found by Scarpinati et al (2009), who reported that this was probably due to the fact that the singletree plots (STPs) design has a lower environmental effect, since the tree is the plot itself
Our study presented higher correlations than those reported in the study by Zhang et al (2015), in which the authors found a moderate correlation (0.61) for individual volume in Pinus spp. between the predicted genotypic values obtained for STPs and a trial with multiple plants per plot

Summary

Introduction

Eucalyptus is a very widely planted genus throughout the world. Species of Eucalyptus are grown for lumber, paper pulp, piling and posts, fuel wood, medicinal products, tannins, and oils and are used as windbreaks and ornamentals.Experimental trials are designed to take into account the evaluative components and to minimize spatial effects to obtain accurate predictions (De Faveri et al, 2016). In forest breeding programs, the planning of clonal and progeny tests presents several challenges to the researcher, the arrangement of the materials in trials, the selection of proper statistical tools for analyses, and the determination of both the plot size and the form and number of plants per plot (Steel and Torrie, 1980; Fins et al, 1992). These types of tests are necessary but are time-consuming and are associated with high costs (Zobel and Talbert, 1984; Jansson et al, 1998). Some authors affirm that plots with a higher number of plants, such as linear plots (LPs), allow more accurate estimations of genetic variability and genetic gains (Lin et al, 1993; Williams and John, 1996; Zhang et al, 2015)

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