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Made available in DSpace on 2019-10-06T15:32:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Microsatellite loci were used to assess pollen contamination and mating patterns in an Eucalyptus urophylla seedling seed orchard (SO2) along with inbreeding and outbreeding depression in a second generation progeny test (PT2) established with SO2 seeds. We measured survival, diameter at breast height (DBH), and height (H) in SO2, PT2, and two other stands (SO1, PT) located at a distance of at least 210 m from SO2. Pollen contamination was substantial (11.9%), with the largest proportion coming from the closer SO1 stand (6.1%) than PT (4.7%) and 1.1% from unknown sources. The pollen dispersal pattern was isolation by distance but reached long distances (600 m). PT2 offspring were mainly the result of outcrossing (92.6%), but mating in SO2 was not random due to self-fertilization (7.4%), mating among relatives (6.6%), correlated mating (13.7%), and high male fertility success of trees with large DBH. Thus, families are a mixture of different levels of relatedness and some inbreeding (12.7%). Inbreeding depression was variable among traits; it was higher for selfing (39.6–49.5%) than mating among relatives (11.6–20.9%) and higher for mating between full-sibs (4.4%) than half-sibs (2.2%). Outbreeding depression was higher for pollen immigration from less improved sources (33.9–41.2%). Non-random mating resulted in a coancestry (0.152) higher than expected for half-sib families and an overestimation of heritability by 17.8%. Our results indicate that isolation distances greater than 600 m are necessary to avoid pollen contamination in Eucalyptus seed orchards. Furthermore, pollen immigration results in outbreeding depression, and selfing results in higher levels of inbreeding depression than mating among related trees. Universidade Estadual de São Paulo (UNESP/Ilha Solteira), Av. Brasil Centro, 56, CP 31, CEP 15385-000, Ilha Solteira Instituto Florestal de São Paulo (IF), CP 1322, CEP 01059-970 Universidade Estadual Paulista (UNESP/Botucatu), Rua José Barbosa de Barros, 1780, CEP 18.603-970 Instituto de Pesquisas e Estudos Florestais (IPEF), Via Comendador Pedro Morganti, 3500, CEP 13.415-000 Eldorado Brasil, Rodovia BR 158 – km 231, CEP 79.641-300 Suzano Papel e Celulose, Avenida Dr. José Lembo, 2215, CEP 18207-780 Universidade Estadual de São Paulo (UNESP/Ilha Solteira), Av. Brasil Centro, 56, CP 31, CEP 15385-000, Ilha Solteira Universidade Estadual Paulista (UNESP/Botucatu), Rua José Barbosa de Barros, 1780, CEP 18.603-970 FAPESP: 2014/03407-7

Made available in DSpace on 2021-06-25T10:27:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-01 While a recent study showed that significant amounts of the nitrogen (N) requirements of young Eucalyptus trees can be provided by nitrogen-fixing trees (NFTs) in mixed-species plantations through short-term belowground N transfer, the consequences of soil fertility on this facilitation process remain unknown. We assessed the effect of fertilization on the percentage of N derived from transfer (%NDFT) from Acacia mangium trees to Eucalyptus trees in mixed-species plantations. A complete randomized block design with two treatments (fertilized vs unfertilized) and three blocks was set up in mixed-species plantations of A. mangium and Eucalyptus in Brazil, with 50% of each species at 2.5 m × 2.5 m spacing. Collection of litterfall and forest floor made it possible to estimate the annual N release from forest floor decomposition between 46 and 58 months after planting, close to harvest age. 15N-NO3- was injected into the stem of one dominant Acacia tree in each plot, 58 months after planting. The x(15N) values of Acacia and Eucalyptus fine roots sampled within 1.8 m of the labelled A. mangium tree were determined at 7, 14, 30 and 60 days after labelling. The x(15N) values in wood, bark, branch and leaf samples were also determined for the 6 labelled Acacia trees and their two closest Eucalyptus neighbours, just before and 60 days after labelling. The amount of N released from forest floor decomposition was 31% higher in fertilized (F+) than in unfertilized (F-) plots. Sixty days after labelling, the aboveground compartments of Eucalyptus trees were significantly 15N enriched in both treatments. The x(15N) values of Acacia fine roots were higher than background values from 7 days after labelling onwards in F+ and 30 days after labelling in F-. The x(15N) values of Eucalyptus fine roots were higher than background values in both treatments, from 30 days after labelling onwards. Mean %NDFT values were 18.0% in F+ and 33.9% in F- over the first 60 days after labelling, and 22.8% in F+ and 67.7% in F- from 30 to 60 days after labelling. Fertilization decreased short-term transfer belowground of N from Acacia trees to Eucalyptus trees. Our study suggests that belowground facilitation processes providing N from NFTs to Eucalyptus trees in mixed-species plantations are more pronounced in low-fertility soils than in nutrient-supplied stands. USP ESALQ Forest Science Department Eco&Sols INRA CIRAD IRD Montpellier SupAgro University of Montpellier CIRAD UMR Eco&Sols UNESP School of Agriculture São Paulo State University ‘Julio de Mesquita Filho,’ Department of Forest Science and Wood UFES IPEF Instituto de Pesquisas e Estudos Florestais UNESP School of Agriculture São Paulo State University ‘Julio de Mesquita Filho,’

Made available in DSpace on 2018-12-11T16:39:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-11-15 We investigated the rate of pollen-mediated flow and realized reproductive success at increasing distances from the source, across fragmented clonal stands of hybrid eucalypts in Brazil by parentage analysis of grown out seedlings using genetic data at 15 microsatellite markers. Two study areas were employed: a pollen donor area composed of a clonal stand of a single pollen donor clone (PD) and a pollen sink (PS) area composed of a mixed clonal stand of two other clones (PS1 and PS2). In the pollen sink area four plots with 30 trees each, located at 25, 200, 400 and 550. m from the PD were established as sink islands. Before flowering, the entire clonal stands of clones PS1 and PS2, with exception of the sink islands were clear cut. Seeds were harvested from five randomly sampled trees in each sink island and the paternity of 15 seedlings per tree, 75 seedlings per island totaling a sample of 300 seedlings, was determined with PD as the alleged father. The self-pollination rate in the sink islands varied from zero to 24%. Paternity assignment to the PD was highest in the island at 25. m (17.3%) and rapidly decreased to 4.0% at 200. m and 2.7% at 550. m, suggesting a pattern of isolation by distance, while revealing a large pollen contribution from unaccounted sources across all islands. Our results in a fragmented clonal site agree with previous estimates of general pollen movement in eucalypt seed orchards, showing that pollination will take place by and large at relatively short distances of less than 200. m, consistent with the expected range of flight of pollinator bees. Nevertheless the exponential distribution observed also indicates that low levels of pollination success are to be expected over longer distances. Our data provide useful guidelines regarding the distance at which seed orchards should be established away from potentially large pollen pressure of clonal stands to minimize unwanted pollen introgression. Furthermore, our results on dispersal rate and distance of pollen have direct implications on gene containment strategies and modeling studies, as pollen-mediated gene flow is one of the key determinants of the potential ecological and biosafety impacts of prospective transgenic eucalypts. Instituto de Pesquisas e Estudos Florestais (IPEF), Avenida Pádua Dias 11, Caixa Postal 530 Instituto Florestal de São Paulo, CP 1322 Faculdade de Engenharia de Ilha Solteira/UNESP, Caixa Postal 31 Plant Genetics Laboratory EMBRAPA Genetic Resources and Biotechnology Universidade Católica de Brasília SGAN Qd 916 Faculdade de Engenharia de Ilha Solteira/UNESP, Caixa Postal 31

Made available in DSpace on 2018-12-11T16:44:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-02-01 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, open-pollinated 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. Instituto de Pesquisas e Estudos Florestais (IPEF), Avenida Pádua Dias 11, Caixa Postal 530 Graduate Program in Forest Sciences FCA/UNESP Instituto Florestal de São Paulo, CP 1322 Faculdade de Engenharia de Ilha Solteira/UNESP, Caixa Postal, 31 Plant Genetics Laboratory EMBRAPA Genetic Resources and Biotechnology Graduate Program in Genomic Sciences Biotechnology and Universidade Católica de Brasília, SGAN Qd 916 ArborGen Tecnologia Florestal, Rua Dr. Emilio Ribas n.174 Graduate Program in Forest Sciences FCA/UNESP Faculdade de Engenharia de Ilha Solteira/UNESP, Caixa Postal, 31

Organized forestry in Brazil began in the late 1960s, stimulated by a government policy which subsidized afforestation programs from 1967 to 1989 to develop an internationally-competitive wood-based industry, managed by the private sector. Currently, planted forests in Brazil total about 6.9 million ha, from which 4.9 million ha is planted with eucalypt (around 25% of world plantation), 1.6 million ha with pine, and 0.42 M ha with other species. Roundwood consumption of forest plantations totaled 170.1 million m(3) in 2011, eucalypt plantation accounted for 80.6% of this total. Most eucalypt plantations are managed in short rotations (6-8 years) and are established in regions with water, nutritional and frost stresses of low to high degrees. The mean annual increment is 40 m(3) ha(-1) year(-1) roundwood, ranging from 25 to 60 m(3) ha(-1) year(-1) depending on the level of environmental stress. Improving natural resources use efficiency by breeding and matching genotypes to sites and using appropriate site management practices is a key challenge to sustain or increase productivity. The wide range of eucalypt species and hybrids with different climatic and edaphic suitability associated with the easy propagation by seeds and cloning allow the adaptation of plantations to various tropical and subtropical regions in Brazil. The possibility of using eucalypt wood in a range of purposes has led large and small enterprises to establish eucalypt forests for multiple uses. The desirable characteristics in association with the accumulated knowledge on eucalypt silviculture encourage the use of this genus in most plantations. The most important factors in the selective process for a genotype are wood characteristics, productivity level, susceptibility to pests and diseases, drought tolerance, especially in tropical regions (frost free), and frost tolerance in subtropical regions (mostly without water deficit). In regions with pronounced seasonality and moderate to long drought periods, the planting of hybrid genotypes predominates, propagated by cloning. Under subtropical conditions, the planting of single species predominates, propagated by seed. Clonal plantations with interspecific hybrids have been fundamental for eucalypt adaptation in regions under water and nutritional stresses. Given the rapid advances in eucalypt breeding, regarding adaptation to water stress and resistance to diseases and pests, and the adoption of clonal propagation techniques, genotypes are rapidly becoming obsolete and are replaced by more productive ones after harvesting. Thus, the replanting of crops has become a common procedure after the second half of the 1990s in Brazil. This paper describes the basic requirements for integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in eucalypt plantations. (c) 2013 Elsevier B.V. All rights reserved.