EVALUATION OF COMPETITION EFFECT IN Eucalyptus PROGENY TESTS

Abstract

Muitos estudos t\ueam recomendado o uso de parcelas pequenas na experimenta\ue7\ue3o florestal, por\ue9m, n\ue3o consideram o aumento da competi\ue7\ue3o intergenot\uedpica que isto acarreta e que pode resultar na sele\ue7\ue3o incorreta dos materiais gen \ue9ticos. O objetivo deste trabalho foi o de avaliar sete covari\ue1veis de competi\ue7\ue3o sobre o car\ue1ter volume de madeira em dois testes de prog \ueanies de Eucalyptus spp. O delineamento utilizado foi de blocos casualizados, com seis repeti\ue7\uf5es de 10 plantas. As sete covari\ue1veis analisadas foram \uedndice de competi\ue7\ue3o de Hegyi (IC), autocompeti\ue7\ue3o (AT), alocompeti\ue7\ue3o (AL), m\ue9dia da autocompeti\ue7\ue3o (MAT), m\ue9dia da alocompeti\ue7\ue3o (MAL) e m\ue9dia aritm \ue9tica dos quatro (M4) e oito vizinhos mais pr\uf3ximos (M8). Essas covari\ue1veis foram avaliadas individualmente bem com em todas as suas poss \uedveis combina\ue7\uf5es, obtendo-se estimativas de componentes de vari \ue2ncias e suas altera\ue7\uf5es com o emprego das mesmas. A competi\ue7\ue3o influenciou os resultados de an\ue1lises de testes de prog \ueanies de eucalipto, em que, autocompeti\ue7\ue3o e alocompeti\ue7\ue3o interferem de forma diferenciada. As covari\ue1veis mais influentes s\ue3o a MAT, a MAL e o IC. A rotina de an\ue1lise que apresentou melhores resultados foi a que incluiu as covari\ue1veis IC/MAT, sendo eficiente na redu\ue7\ue3o do efeito competicional em testes de prog \ueanies de eucalipto.Many studies have recommended the use of small plots for forest experiments, although they do not consider the inter-genotype competition increase. If this competition is not isolated from the mathematics model, it can lead to incorrect selection of genetic materials. The aim of this work was to evaluate the effect of seven competition covariates in two Eucalyptus spp. progeny tests. Data from the two half-sib eucalyptus progenies were analyzed, using the randomized blocks design. The seven analyzed covariates were HegyI\u2019s competition index (IC), self-competition (AT), alo competition (AL), self-competition mean (MAT), alo competition mean (MAL), and arithmetic means of four (M4) and eight (M8) nearest neighbors. Individual and combined analyses of covariates were used for the wood volume trait. All the variance components and the changes caused by covariates use were evaluated. The competition affects the results of eucalypt progeny analysis in different ways, according to its type, self or alo competition. Most influential covariates were MAT, MAL and IC. Most promising results of competition effects reduction were observed for the IC/ MAT covariates inclusion in eucalypt progeny tests