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ResumoPopulações de Eucalyptus grandis foram introduzidas no Brasil a partir de Queensland e New South Wales, Austrália. No entanto, no Brasil, estas plantas têm sido severamente prejudicadas pela ferrugem (Puccinia psidii Winter). Portanto, objetivamos estimar os parâmetros do sistema de reprodução e a herdabilidade para resistência a ferrugem em E. grandis por meio de um teste de progênies. Nós avaliamos a resistência a ferrugem em vinte e cinco progênies de polinização aberta, que foram severamente afetadas por P. psidii, utilizando quatro marcadores de microssatélites. A taxa de cruzamento foi significativamente menor do que a unidade ( = 0.782) e a diferença entre as taxas multilocus e unilocus foi significativamente maior do que zero ( = 0.077). Esses resultados mostram que algumas sementes eram endogâmicas como confirmado pelo índice de fixação ( = 0,144, P< 0,05). Além disso, a correlação de paternidade ( = 0,102) indicou um pequeno número de irmãos-completos dentro de progênies. O coeficiente de parentesco estimado dentro de progênies ( ) foi significativamente maior (0,421) do que o esperado para meios--irmãos (0,25). O coeficiente de herdabilidade entre progênies ( = 0,956), bem como em nível individual ( = 0,634) e dentro de progênies ( = 0,515) foram elevados. Nossos resultados evidenciaram forte controle genético para o caráter resistência à ferrugem, indicando que o melhoramento dessas populações pode ser feito pela seleção massal ou pela seleção simultânea entre e dentro de progênies.Palavras-chave: Parâmetros genéticos; teste de progênie; Puccinia psidii; sistema de reprodução. AbstractPopulations of Eucalyptus grandis were introduced into Brazil from Queensland and New South Wales, Australia. However, in Brazil, these plants have been severely injured by rust (Puccinia psidii Winter). Therefore, we aimed at estimating mating system parameters and heritability of rust resistance in E. grandis through progeny testing. We evaluated rust resistance in twenty-five open-pollinated progenies severely affected by P. psidii using four microsatellite markers. Outcrossing rate was significantly lower than unity ( = 0.782), and the difference between multilocus and single-locus was significantly higher than zero ( = 0.077). These findings highlight that a few seeds are inbred lines as confirmed by the fixation index ( = 0.144, P< 0.05). Furthermore, the paternity correlation ( = 0.102) indicated a small number of full-sibs within progenies. The estimated relatedness coefficient within progenies ( ) was significantly higher (0.421) than that expected for half-sibs (0.25). The mean heritability coefficient among progenies ( = 0.956), as well as at the individual level ( = 0.634) and within a progeny ( = 0.515) were high. Given that, our results indicated a strong genetic control on rust resistance and the feasibility in improving the populations by mass selection for both among and within progenies.

The aim of this work was to analyze the population structure and the spatial distribution of Copaifera langsdorffii Desf. in two areas of the Cerrado biome. The study was carried out in two physiognomies of the Cerrado biome: cerrado sensu stricto and cerradão, both located in the southern region of the state of Tocantins. The spatial distribution was evaluated using Morisita and dispersion indices, as well as the population structure of C. langsdorffii. We quantified 318 individuals of C. langsdorffii in the two studied areas. There were 200 individuals sampled in the cerrado sensu stricto and 118 in the area of cerradão. Regarding the type of spatial distribution of individuals of C. langsdorffii, the value found for the Morisita index was 2.67 in the physiognomy of cerrado sensu stricto, suggesting grouped spatial distribution (I >1). The dispersion index calculation showed that, in fact, the spatial distribution of the individuals sampled in the two areas was the grouped type; for the area of cerrado sensu stricto, the variance (S2) found was 24.21 and for the cerradão it was 9.67, higher than their means 10.00 and 9.67 respectively. By analyzing the age structure of the population of C. langsdorffii, we found a typical trend of the inverted-J curve, suggesting that the areas studied are self-regenerating communities composed of young and developing individuals.

This study aimed to quantify the accumulated litter of a fragment of cerrado sensu stricto, besides estimating the organic carbon stored from the organic matter. We conducted the study in a sensu stricto cerrado fragment in the municipality of Formoso do Araguaia, State of Tocantins, where samples of litter were collected in six random plots of 10 m x 50 m (500m2) using a 0.5 m x 0.5 m iron template by throwing it into the ground to collect the material. We separated the collected litter into two fractions, dry and green litter. Those collected were conditioned in paper containers for oven drying at 70°C for 48 h. It was weighed 1.5 g of the biomass ground in porcelain crucibles, which were dried in an oven at 105°C for 24h, then in the muffle at 550°C for 3h, at the Madeira Laboratory from the Federal University of Tocantins. For the litter, it was quantified 4.36 t ha-1 (value below the ones found in the literature), 69.08% of organic matter for the dry material, 95.42% of organic matter for the green material, 0.546 t ha-1 of organic carbon in the dry material, 0.769 t ha-1 of organic carbon in the green material.

The objective of this study was to verify changes in the vegetative growth of Peltophorum dubium before flowering induced by the application of plant growth regulators. The experimental design was randomized blocks with three replications of four plants/plot. The variables height, stem diameter, chlorophyll content, and peroxidase activity were evaluated. Statistical analysis was performed using SAS. Plant size reduction (73%) was induced by the plant inhibitor paclobutrazol. Plant height growth was stimulated by GA3 (18%). Ethephon caused death of the apical buds.