Confined field trials of genetically modified (GM) trees are the essential step toward the identification of the most productive cultivars and the assessment of the likely environmental impacts of the GM trees including the potential for gene flow by pollen and distance dispersal by seeds. Our study investigated the potential for wildling establishment and realized pollen flow from a clonal GM eucalypt field trial in Southeastern Brazil. The GM eucalypt stand was established in 2009, surrounded by a 3 m wide forest road and signal grass (Bracharia sp.) fields. No seedling regeneration was found between 2010 and 2014 in and around the stand, confirming the expectations of the unlikelihood of eucalypt seedling establishment based on its limited invasive potential in competitive tropical environments. In 2014, openpollinated seeds were collected from 28 non-GM eucalypts located between three and 650 m distance from the GM trial. A total of 420 seedlings were grown in a greenhouse and screened for the presence of the transgenic construct by a multiplexed PCR assay targeting two transgenes and an internal control. The highest average transgene pollen flow (16%) was seen at short distances (3-15 m), rapidly diminishing to 3% by a 240 m distance and continued at this low rate up to the furthest distance assessed (650 m) from the GM trial. The negative exponential distribution of GM pollination success was similar to that observed in non-GM eucalypt pollen flow studies, indicating that low levels of effective pollination are expected over long distances. To the best of our knowledge, this is the first experimental assessments of realized pollen flow measured by the effective production of seedlings from a genetically modified tree in field conditions.
Eucalyptus planted forests contribute to maximizing lumber production but problems such as longitudinal growth strain can negatively influence the quality of the products. Knowing dendrometric variables and wood properties can help in the prediction of longitudinal growth strain, mainly with the help of artificial intelligence. Thus, the aim of this research was to evaluate the use of artificial neural networks to predict longitudinal growth strain in Eucalyptus trees based on dendrometric variables, spacing between trees and wood density. The longitudinal growth strain was measured in trees of four Eucalyptus clones planted in three spacings. The diameter and height of each tree were measured. The basic wood density was determined. Artificial neural networks were used to estimate longitudinal growth strain as a function of dendrometric variables, tree spacing
RESUMO O estudo foi desenvolvido para avaliar o potencial de cinco novos clones de eucalipto para a produção de madeira serrada. Foram utilizadas toras de três clones do híbrido Eucalyptus grandis x Eucalyptus urophylla, um clone de Eucalyptus grandis e um clone de Eucalyptus urophylla. Em todos os materiais genéticos foram avaliados a porcentagem de cerne, o índice de rachaduras de topo das toras e das tábuas, o arqueamento e o encurvamento verde e seco nas tábuas. Houve influência significativa dos clones na qualidade das toras e na qualidade da madeira serrada. Para o arqueamento (verde e seco) e encurvamento (verde) todos os clones foram classificados com empenamento leve. Após o desdobro, os clones 3 (Eucalyptus grandis x Eucalyptus urophylla), clone 4 (Eucalyptus grandis) e clone 5 (Eucalyptus grandis x Eucalyptus urophylla) apresentaram rachadura leve. Sendo assim, os clones 3, 4 e 5 mostraram-se como potenciais fontes de matéria prima para produção de madeira serrada. Palavras-chave: Qualidade da tora; Qualidade da madeira; Processamento da madeira. Quality of the log and wood of Eucalyptus clones for use in lumber industry ABSTRACT The study was conducted to evaluate the potential of five new eucalyptus clones for lumber production. Logs of three clones of the hybrid of Eucalyptus grandis x Eucalyptus urophylla, one clone of Eucalyptus grandis and one clone of Eucalyptus urophylla were used. In all genetic materials were evaluated the core percentage and the top splits index for the logs and the spring, bow and splits for the green and dry boards. The clones had a significant influence on the logs and lumber quality. Considering spring (green and dry) and bow (green), all clones were classified with light warping. After sawing, the clone 3 (Eucalyptus grandis x Eucalyptus urophylla), clone 4 (Eucalyptus grandis) and clone 5 (Eucalyptus grandis x Eucalyptus urophylla) presented light splits. Therefore, the clones 3, 4 and 5 proved to be potential sources of raw material for lumber production.
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