Abstract Spatial and non-spatial analyses were conducted to estimate genetic parameters for the traits leaf mass weight (LMW), crown height (CH), crown diameter (CD), and crown volume (CV) for ages between 21 and 27 in 10 half-sib progeny trials of Ilex paraguariensis St. Hill. The spatial model gave a better fit than the base model in 87.2% of the analysed dataset, with reductions in residual and plot variances. The narrow-sense heritability estimates ranged from low to moderate for LMW trait (0.01 to 0.43) and from low to high for crown traits (0.08 to 0.74). The additive genetic coefficient of variation for the LMW trait was over 12.4%, while for CH and CD it was below 10%. Generally, the additive genetic correlations ( r ^ a ) between the LMW evaluations and between LMW and crown traits were greater than 0.70.

ABSTRACT Forest tree breeding activities in plantations with exotic species implies several instances of material selection where genetic variation can be affected. The objective of the work was to verify the genetic variability present in two plantations of Pinus caribaea var. hondurensis by microsatellite markers, initially designed for Pinus taeda fluorescent-labeled. Thus, 299 individuals were analyzed using eight polymorphic microsatellite markers. The results indicate that both plantations have adequate levels of genetic diversity that are representative of the Pinus genus. Through the Bayesian method, it was possible to detect two different population genetic structures (K = 2) between both plantations analyzed. In conclusion, this study suggests that microsatellites markers are useful tools to monitor genetic variation in genetic breeding programs. The genetic diversity estimated in both plantations is similar and typical for Pinus plantations, and as expected, there was a slight decrease in genetic variability in the commercial plantation in comparation with the base plantation.

RESUMO As atividades de melhoramento genético florestal em plantios com espécies exóticas envolvem várias instâncias de seleção de material, onde a variação genética pode ser afetada. O objetivo do trabalho foi verificar a variabilidade genética presente em duas plantações de Pinus caribaea var. hondurensis através de marcadores microssatélites, inicialmente desenhados para Pinus taeda. Assim, 299 indivíduos foram analisados utilizando oito marcadores microssatélites polimórficos. Os resultados indicam que ambas plantações têm níveis adequados de diversidade genética que são representativos do gênero Pinus. Através do método Bayesiano, foi possível detectar duas populações genéticas estruturadas (K = 2) entre as duas plantações analisadas. Em conclusão, este estudo sugere que os marcadores microssatélites são ferramentas úteis para monitorar a variação genética nos programas de melhoramento genético. A diversidade genética estimada em ambas plantações é semelhante e típica das plantações de Pinus, e como se esperava verificou-se uma ligeira diminuição da variabilidade genética na plantação comercial, em comparação com a plantação base.

Abstract: This work aimed to evaluate radial variation of tracheid morphology for hybrid pines. Radial increments cores were extracted from trees of hybrid pine “F1 INTA-PINDO” in two trials. The samples were taken at 1,30 m in height, they were dissociated, and the anatomical characteristics of individual tracheids obtained from the latewood fraction of growth rings 4, 7, 10, and 11 were measured by optical microscopy with image analysis. To obtain the microfibrillar angle, the technique "through individual tracheid pit apertures" was used. For microfibrillar angle within each age, significant statistical differences were found between sites and families for a confidence level of 95%, whereas the variations were not significant for others studied properties. Important changes with considered ages were observed in the cell morphology of the tracheids. The mean values of microfibrillar angle, lumen width, and the total width of tracheids decreased with age, regardless of sites and evaluated families. The mean values of cell wall-thickness and cell-wall ratio increased with age. These results indicate that wood properties would not be uniform in the radial direction and they must be taken into account for certain uses. Families with better growth performance and desirable parameters for structural wood quality were identified. The outstanding families belong to the best positions of growth genetic ranking. It is concluded that at 11 years old, this taxon produces mature wood, due to the characteristics of its cell morphology.

Resumen: El objetivo de este trabajo fue evaluar la variación radial de la morfología de las traqueidas de pinos híbridos. Se extrajeron tarugos radiales de árboles de pino híbrido “F1 INTA-PINDO”, en dos ensayos. Las muestras se tomaron a 1,30 m de altura, se disociaron y se midieron las características anatómicas de las traqueidas individuales obtenidas de la fracción de madera tardía de los anillos de crecimiento 4, 7, 10 y 11 mediante microscopía óptica con análisis de imagen. Para la obtención del ángulo microfibrilar se utilizó la técnica a través de las puntuaciones en traqueidas individuales. Para el ángulo microfibrilar dentro de cada edad, se encontraron diferencias estadísticas significativas entre sitios y familias para un nivel de confianza del 95 %, mientras que las variaciones no fueron significativas para las demás propiedades estudiadas. Se observaron cambios importantes en la morfología celular de las traqueidas para las edades consideradas. Los valores medios de ángulo microfibrilar, ancho del lumen y ancho total de las traqueidas disminuyeron con la edad, independientemente del sitio y las familias evaluadas. Los valores medios de espesor y la proporción de pared celular aumentaron con la edad. Estos resultados indican que las propiedades de la madera no serían uniformes en el sentido radial y deben ser tenidas en cuenta al momento de utilizarlas para determinados usos. Se identificaron familias con mejor performance en crecimiento y parámetros deseables para la calidad estructural de la madera, las mismas pertenecen a las mejores posiciones del ranking genético de crecimiento. Se concluye que, a los 11 años de edad este taxón produce madera madura, debido a las características de su morfología celular.

Abstract We report the first comprehensive multilocus molecular characterization of cultivated Ilex paraguariensis plants belonging to a breeding program. Using nuclear and homologous chloroplastidic molecular markers, we have genotyped 158 plants from four plantation sites. Analyses of the nuclear data (187 variable dominant loci) allowed detecting high diversity (0.569), the occurrence of four distinct genetic clusters, and a low but significant differentiation among sites. Additionally, 20 chloroplastidic alleles were identified applying five microsatellite polymorphic markers, and a high chloroplastidic diversity was recognized (0.505); two haplogroups were distinguished amongst the 63 haplotypes detected. Our results from both nuclear and plastidic markers indicate that most genetic variation reside within plantations sites (≥ 95%), and that these plantations were established on highly variable materials (either as seeds or plantlets) derived from, at least, 63 maternal lineages. Moreover, our study suggests that the genetic structure within each plantation site was most likely shaped by past admixture favored by farmers´ practices during the establishment of each plantation. Also, subsequent constraints in gene flow and/or a low level of shared polymorphism among plantations could have contributed to current structure.