DENDROMETRIC AND CHEMICAL TRAITS AND BASIC DENSITY WOOD OF Eucalyptus grandis X Eucalyptus urophylla HYBRIDS

O presente trabalho avaliou caracter\uedsticas dendrom\ue9tricas, qu\uedmicas e a densidade b\ue1sica da madeira de cinco h\uedbridos de Eucalyptus grandis x Eucalyptus urophylla , com 2,25 anos de idade. O experimento foi implantando no espa\ue7amento 3,5 x 2 m, com 35 repeti\ue7\uf5es e parcelas de uma planta. Quatro repeti\ue7\uf5es do experimento foram cortadas avaliando-se o di\ue2metro a altura do peito (DAP, a 1,3 m do solo), altura total e comercial, biomassa seca de folhas, galhos, madeira e casca, volume com e sem casca e volume de casca. Das \ue1rvores abatidas foram retirados discos de 5 cm de espessura no DAP e a 0 (base), 25, 50, 75 e 100% da altura comercial, para determina\ue7\ue3o da densidade b\ue1sica e caracteriza\ue7\ue3o qu\uedmica da madeira. Os dados foram submetidos \ue0 an\ue1lise de vari\ue2ncia e compara\ue7\ue3o de m\ue9dias pelo teste de Tukey a 5% de probabilidade. Os clones de Eucalyptus grandis x Eucalyptus urophylla diferiram quanto ao volume e biomassa com destaque para o C5 com valores superiores aos demais clones. A densidade b\ue1sica da madeira foi maior na base da \ue1rvore; nas demais posi\ue7\uf5es de amostragem, os valores de densidade foram semelhantes entre si; dentre os clones, o C5 apresentou densidade b\ue1sica da madeira superior ao C3 e ao C4, assim como o C2 superou o C3. As caracter\uedsticas qu\uedmicas da madeira foram semelhantes entre os clones e, apesar da avalia\ue7\ue3o ter sido realizada em plantas jovens, os clones demonstraram bom potencial em Jaboticabal - SP.The present study evaluated the dendrometric, chemical and basic density wood from five hybrids of Eucalyptus grandis x Eucalyptus urophylla at 2.25 years old. The experiment was implemented in 3.5 x 2 meters spacing, with 35 replicates of a single tree. Four replicates were harvester, we evaluated the diameter at breast height (DBH, 1.3 m above the ground), total and commercial height, biomass of leaves, branches, wood and bark, volume with and no bark and volume of bark. Besides it was obtained discs at 0, 25, 50, 75 e 100% of commercial height and at DBH for the determination of wood density and chemical characterization of wood. Data were subjected to analysis of variance and comparison of means by Tukey\u2019s test at 5 % probability. Clones of Eucalyptus grandis x Eucalyptus urophylla exhibited different growth highlighting the C5 with greater volumetric and biomass. The basic density wood is higher when assessed at base of tree, but it was verified similar values in other positions of the stem. Among the clones, the basic density wood of C5 is higher than C3 and C4 and C2 is higher than C3. The chemicals wood characteristics were similar among clones of Eucalyptus grandis x Eucalyptus urophylla. Despite the evaluation have been performed on young plants, 2.25 years old, the clones have demonstrated satisfactory potential in Jaboticabal, SP

Early selection viability in Eucalyptus spp clonal tests

Com o objetivo de avaliar a efici\ueancia da sele\ue7\ue3o precoce em Eucalyptus spp. foram usados dados de dois testes clonais avaliados quanto ao crescimento em altura (ALT), di\ue2metro \ue0 altura do peito (DAP) e volume individual de madeira (VOL) aos 25, 50 e 72 meses de idade. O delineamento experimental nos dois testes clonais foi o de blocos casualizados, com trinta tratamentos (clones), seis repeti\ue7\uf5es, sendo um deles com seis e o outro com dez plantas em linha por parcela, no espa\ue7amento de 3,0 m x 3,0 m. Foi feita a an\ue1lise de vari\ue2ncia para cada caracter e idade. Foram obtidas as estimativas de coeficiente de determina\ue7\ue3o genot\uedpico e de correla\ue7\uf5es genot\uedpicas entre os caracteres nas idades juvenis e na idade de rota\ue7\ue3o. Para verificar a viabilidade da aplica\ue7\ue3o da sele\ue7\ue3o precoce, foi simulada a sele\ue7\ue3o de 30% dos clones nas idades juvenis e na idade de rota\ue7\ue3o para cada um dos caracteres e idades avaliadas, obtendo-se as estimativas de ganhos gen\ue9ticos com a sele\ue7\ue3o direta e indireta. Houve diferen\ue7as significativas entre os clones avaliados nos dois experimentos para todos os caracteres e idades. Com base nos resultados obtidos, \ue9 poss\uedvel efetuar a sele\ue7\ue3o precoce aos 2 anos de idade sobre o caracter DAP em testes clonais de eucalipto.With the aim of evaluating Eucalyptus spp. for early selection efficiency, the height (HGT), diameter at breast height (DBH) and individual wood volume (VOL) of two clonal tests were assessed at the ages of 25, 50, and 72 months. The experimental design consisted of randomized blocks, containing 30 treatments (clones), 6 replications and linear plots, one of them with 6 plants and the other with 10 plants, at the spacing of 3.0m x 3.0m. Variance analysis for each trait and age were carried out in the trials. The estimates of genotypic determination coefficient and the correlation between the early and mature ages for each trait were obtained. In order to confirm the viability of early selection, a simulated selection was performed at young and mature ages, adopting 30% of selection proportion for each trait and age considered. The genetic gains were estimated by using both direct and indirect selection. There were significant differences among clones evaluated in the two experiments for all traits and ages. Based on the results obtained for DBH in eucalyptus clonal tests, the use of early selection at the age of 2 years is feasible

EVALUATION OF COMPETITION EFFECT IN Eucalyptus PROGENY TESTS

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