CARACTERÍSTICAS DENDROMÉTRICAS, QUÍMICAS E DENSIDADE BÁSICA DA MADEIRA DE HÍBRIDOS DE Eucalyptus grandis X Eucalyptus urophylla

http://dx.doi.org/10.5902/1980509821119The 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’s 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.http://dx.doi.org/10.5902/1980509821119O presente trabalho avaliou características dendrométricas, químicas e a densidade básica da madeira de cinco híbridos de Eucalyptus grandis x Eucalyptus urophylla, com 2,25 anos de idade. O experimento foi implantando no espaçamento 3,5 x 2 m, com 35 repetições e parcelas de uma planta. Quatro repetições do experimento foram cortadas avaliando-se o diâmetro 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 árvores abatidas foram retirados discos de 5 cm de espessura no DAP e a 0 (base), 25, 50, 75 e 100% da altura comercial, para determinação da densidade básica e caracterização química da madeira. Os dados foram submetidos à análise de variância e comparação de médias 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 básica da madeira foi maior na base da árvore; nas demais posições de amostragem, os valores de densidade foram semelhantes entre si; dentre os clones, o C5 apresentou densidade básica da madeira superior ao C3 e ao C4, assim como o C2 superou o C3. As características químicas da madeira foram semelhantes entre os clones e, apesar da avaliação ter sido realizada em plantas jovens, os clones demonstraram bom potencial em Jaboticabal - SP

Minimizing inter-genotypic competition effects to predict genetic values and selection in forestry genetic tests

The effect of competition is an important source of variation in breeding experiments. This study aimed to compare the selection of plants of open-pollinated families of Eucalyptus with and without the use of competition covariables. Genetic values were determined for each family and tree and for the traits height, diameter at breast height and timber volume in a randomized block design, resulting in the variance components, genetic parameters, selection gains, effective size and selection coincidence, with and without the use of covariables. Intergenotypic competition is an important factor of environmental variation. The use of competition covariables generally reduces the estimates of variance components and influences genetic gains in the studied traits. Intergenotypic competition biases the selection of open-pollinated eucalypt progenies, and can result in an erroneous choice of superior genotypes; the inclusion of covariables in the model reduces this influence

Tetrazolium test in Copaifera langsdorffii and Schizolobium parahyba seeds

Este trabalho objetivou padronizar o teste de tetrazólio para avaliação da viabilidade de sementes de copaíba e guapuruvu. Avaliou as seguintes metodologias: sementes escarificadas mecanicamente e embebidas por 24 e 48 horas, com posterior retirada do tegumento e imersas em solução de tetrazólio a 0,075, 0,10 e 0,20% por 2, 3 e 4 horas, a 35 ºC, no escuro. As metodologias avaliadas que foram eficientes na obtenção de coloração satisfatória, permitindo a diferenciação dos tecidos, e na avaliação da qualidade fisiológica das sementes, quando comparadas com o teste padrão de germinação, foram: para a espécie copaíba, sementes escarificadas e embebidas por 24 horas, a 35 ºC, com posterior retirada do tegumento, submetidas a solução de tetrazólio a 0,20% por 4 horas, a 35 ºC, no escuro; e para a espécie guapuruvu, sementes escarificadas e embebidas por 48 horas, a 35 ºC, com posterior retirada do tegumento, submetidas a solução de tetrazólio a 0,10% por 4 horas, a 35 ºC, no escuro.Palavras-chave: Sementes florestais; teste rápido; copaíba; guapuruvu. AbstractTetrazolium test in Copaifera langsdorffii and Schizolobium parahyba seeds. This research aimed to standardize the tetrazolium test for evaluation of viability of Copaifera langsdorffii Desf. and Schizolobium parahyba Vell. Blake seeds. It evaluated the following methodologies: seeds scarificated mechanically and soaked up by 24 and 48 hours, with posterior seed coat removal and immersed in tetrazolium solution at 0.075; 0.10 and 0.20% for 2, 3 and 4 hours, 35 ºC, the dark one. The evaluated methodologies that had been efficient in the attainment of satisfactory coloration, allowing the differentiation of tissues, and in the evaluation of the physiological quality of the seeds when compared with the germination test, had been: for the species Copaifera langsdorffii, seeds scarificated and soaked up by 24 hours, 35 ºC, with posterior seed coat removal, submitted to the tetrazolium solution 0.20% for 4 hours, 35 ºC, in the dark one, and for the species guapuruvu, seeds scarificated and soaked up by 48 hours, 35 ºC, with posterior seed coat removal, submitted to the tetrazolium solution 0.10% for 4 hours, 35 ºC, in the dark one.Keywords: Forest seeds; fast test; Copaifera langsdorffii; Schizolobium parahyba.This research aimed to standardize the tetrazolium test for evaluation of viability of Copaifera langsdorffii Desf. and Schizolobium parahyba Vell. Blake seeds. It evaluated the following methodologies: seeds scarificated mechanically and soaked up by 24 and 48 hours, with posterior seed coat removal and immersed in tetrazolium solution at 0.075; 0.10 and 0.20% for 2, 3 and 4 hours, 35 ºC, the dark one. The evaluated methodologies that had been efficient in the attainment of satisfactory coloration, allowing the differentiation of tissues, and in the evaluation of the physiological quality of the seeds when compared with the germination test, had been: for the species Copaifera langsdorffii, seeds scarificated and soaked up by 24 hours, 35 ºC, with posterior seed coat removal, submitted to the tetrazolium solution 0.20% for 4 hours, 35 ºC, in the dark one, and for the species guapuruvu, seeds scarificated and soaked up by 48 hours, 35 ºC, with posterior seed coat removal, submitted to the tetrazolium solution 0.10% for 4 hours, 35 ºC, in the dark one

Temperaturas para a germinação de sementes de capixingui (Croton floribundus - Spreng - Euphorbiaceae)

O presente trabalho objetivou avaliar a influência de diferentes temperaturas e da imersão em água na germinação de sementes de capixingui (Croton floribundus Spreng). Inicialmente, as sementes foram submetidas à germinação a 15, 20, 25, 30, 35, 40, 20-30 e 25-35ºC, com e sem imersão das mesmas em água fria (temperatura ambiente) por duas horas. Posteriormente, sementes sem imersão prévia em água fria foram submetidas à germinação a 20-25, 25-30, 30-35, 20-30, 25-35 e 20-35ºC. Foram avaliadas a porcentagem e a velocidade de germinação das sementes, a matéria seca e o comprimento de plântulas. Os dados foram submetidos à análise de variância, no delineamento inteiramente casualizado (DIC) e esquema fatorial 8 x 2 no primeiro experimento e no DIC com seis tratamentos no segundo experimento, com quatro repetições de 25 sementes, seguido da comparação de médias (Tukey a 5%). Não houve germinação a 15, 20 e 40ºC e esta foi mínima a 25ºC. As temperaturas alternadas de 20-30 e de 25-35ºC favoreceram o processo germinativo. A imersão das sementes em água fria não favoreceu a taxa de germinação. No segundo experimento, a maior germinação ocorreu a 20-30ºC. Assim, pode-se recomendar a temperatura de 20-30ºC para a condução do teste de germinação de sementes de capixingui, o qual pode ser encerrado aos 28 dias.The aim of this research was to evaluate the influence of different temperatures, constant and alternating, on the germination of Croton floribundus­ Spreng (Euphorbiaceae) seeds and also the efficiency of a previous soaking treatment in cold water (room temperature). In the first test, the seeds were submitted to the standard germination test at the following temperatures 15, 20, 25, 30, 35, 40, 20-30 and 25-35ºC, with and without previous soaking treatment. In the second test, the seeds were submitted to germination at temperatures of 20-25, 25-30, 30-35, 20-30, 25-35 and 20-35ºC. The characteristics evaluated were the percentage and speed of germination and seedling mass and length, with four replications of 25 seeds. A completely randomized design was used with 8x2 treatments in the first essay and six treatments in the second. The averages were compared by the Tukey test (P<0.05). In the first experiment, germination was not observed at 15, 20 and 40ºC; at 25ºC the germination was minimum; high germination was observed at the alternating temperatures. Soaking in cold water did not improve the germination. In the second experiment, the highest germination rate was observed at 20-30ºC. Thus, the standard germination test can be conducted at 20-30ºC for 28 days.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES