RESUMO: A mangabeira é uma espécie frutífera cujas populações naturais se encontram fragmentadas por ações antrópicas. Desse modo, são necessários estudos sobre a avaliação do impacto da fragmentação sobre a diversidade e estrutura genética dessas populações para o estabelecimento de estratégias de conservação adequadas. No presente estudo, foram utilizados dados de análises com marcadores microssatélites em simulações computacionais para estimar as taxas de migração e autofecundação de seis populações de mangaba. As populações estudadas estão localizadas nos estados nordestinos do Ceará, Pernambuco e Sergipe. Foram testadas diferentes taxas de autofecundação e migração, e selecionada a combinação que apresentou valores de heterozigosidade observada e esperada mais próximos dos obtidos com marcadores microssatélites. Com base nas simulações, a autofecundação foi de 0,3 e a taxa de migração variou de 0,5 a 0,6, valores que podem ter conduzido ao aumento da endogamia e deriva genética, resultando em baixa diversidade genética. Recomenda-se a expansão da área e a redução de perturbações para promover a ocorrência de polinizadores, que desempenham um papel importante no aumento da diversidade genética.

ABSTRACT: Mangaba tree is a fruit tree species whose natural populations are fragmented by anthropic actions. For this reason, studies assessing the impact of fragmentation on the diversity and genetic structure of these populations are required in order to establish suitable conservation strategies. In our study, we used data from analyzes through microsatellite markers in computer simulations to estimate the rates of migration and selfing of six mangaba populations. The studied populations are located in the northeastern states of Ceará, Pernambuco and Sergipe. We tested different selfing and migration rates and selected the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers. According to our simulations, selfing and migration were moderate. This may have led to an increase in inbreeding and genetic drift, resulting in low genetic diversity. We recommend expanding the area and reducing disturbance to promote the occurrence of pollinators, which play an important role in increasing genetic diversity.

ABSTRACT Microsatellites are short sequence repeats that make up the genomes of eukaryotes and prokaryotes. They are of great importance as DNA markers for studies in several fields of genetics. In the present review, we searched for studies published in the five years period of 2017 to 2021 regarding the use of microsatellites in studies with forest tree species from the Brazilian biomes, in order to examine the importance of these markers for forest resources conservation. We searched scientific papers in journals indexed on the Scopus and Web of Science databases. There were found 38 peer reviewed articles that used microsatellites in the Brazilian biomes. The Atlantic Forest was the biome with more studies (35.9 %) and most of the studies were published in 2018 (34.2 %). In addition, most of the studied species belonged to the Fabaceae family (34.2 %). The conclusions and recommendations made in these studies ratify the great contribution of microsatellite markers in the conservation of native forest species in Brazilian biomes.

ABSTRACT Gene flow allows connectivity of geographically isolated populations and which genetic diversity is reduced. Understanding how gene flow occurs is essential to conservation and selection of priority populations for intervention. In this study, the rates of migration and selfing of Copaifera langsdorffii Desf. sampled in Cerrado fragments in the State of São Paulo, Brazil, were estimated through computer simulations. Different selfing and migration rates were tested and the combination that showed values of observed and expected heterozygosity closest to those previously obtained with microsatellite markers was selected. According to the simulations, selfing and migration were low. Due to the high geographical distances among the fragments, gene flow was limited and may have led to low genetic diversity in the fragments. It is recommend enriching the area with high genetic diversity germplasm and reducing disturbance to promote the occurrence of pollinators, in order to increase the genetic diversity.

ABSTRACT Eugenia involucrata is an important Brazilian forest species, which it can be used for timber, such as firewood and charcoal, and non-timber purposes, for culinary and medicinal use. Considering the limitations of its seminal reproduction, vegetative propagation, particularly by micropropagation, becomes an alternative for plantlets production. In this study we evaluated the effect of the phytoregulators 6-benzylaminopurine (BAP) and 3-indolebutyric acid (IBA) on the in vitro multiplication stage of nodal segments. The experiment was carried out in a completely randomized design, in a 3 x 4 factorial array, the main factors were BAP (0; 0.1 or 0.2 µM) and IBA (0; 10; 20 or 30 µM). After 60 days of in vitro inoculation, evaluations on the the number of buds, number of shoots, number of leaves, callus formation (%) and number of roots per explant were carried out. BAP had not significant effect, however, the use of IBA alone favours the callogenesis and negatively affected leaves, shoots and roots formation. A moderate multiplication rate was obtained when considering in vitro bud formation. BAP and IBA are dispensable in in vitro multiplication of E. involucrata.

ABSTRACT Decontamination of explants is a requirement for micropropagation efficiency. The aim of this work was to evaluate the use of the antibiotic streptomycin sulfate (SE) in the control of endogenous bacterias in micropropagated nodal segments of Eugenia involucrata. The treatments were: T1 (explants without previous contamination); T2 (explants with previous contamination); T3 (explants without contamination and immersed in SE solution at 100 mg L-1 for 5 min); T4 (contaminated explants and immersed in SE solution at 100 mg L-1 for 5 min); T5 (explants without contamination and inoculated in a medium containing 100 mg L-1 of SE); and T6 (contaminated explants and inoculated in medium containing 100 mg L-1 of SE). After 30 days of in vitro culture, there was no significant effect on the variables survival (mean 94.44%) and fungal contamination (mean 6.94%). The highest bacterial contamination was observed in T3 and T4 (100%), whereas in T5 (16.67%) the lowest average was observed. In T5 was observed the greatest number of leaves (mean 3.83), which differed statistically from T2 and T4, which presented the lowest averages. Immersion does not control the bacteria proliferation. Inoculation in the absence of prior contamination controls bacteria proliferation whereas inoculation with contaminated explants does not reduce it. Leaf development is hindered by the presence of bacteria.

RESUMO A descontaminação dos explantes é requisito para a eficiência da micropropagação. O trabalho teve como objetivo avaliar o modo de utilização do antibiótico sulfato de estreptomicina (SE) no controle de bactérias endógenas em segmentos nodais micropropagados de Eugenia involucrata. Os tratamentos foram: T1 (explantes sem contaminação prévia); T2 (explantes com contaminação prévia); T3 (explantes sem contaminação e imersos em solução de SE a 100 mg L-1 durante 5 min); T4 (explantes com contaminação e imersos em solução de SE a 100 mg L-1 durante 5 min); T5 (explantes sem contaminação e inoculados em meio contendo 100 mg L-1 de SE); e T6 (explantes com contaminação e inoculados em meio contendo 100 mg L-1 de SE). Decorridos 30 dias de cultivo in vitro não houve efeito significativo sobre as variáveis sobrevivência (média de 94,44%) e contaminação fúngica (média 6,94%). As maiores contaminações bacterianas foram observadas em T3 e T4 (100%), já em T5 (16,67%) observou-se a menor média. Ocorreu maior número de folhas em T5 (3,83), que diferiu estatisticamente de T2 e T4, os quais apresentaram a menor média. A imersão não controla a proliferação de bactérias. A inoculação na ausência de contaminação prévia controla a proliferação, mas não reduz as bactérias quando há contaminação. O desenvolvimento das folhas é prejudicado pela presença de bactérias.

Resumo O objetivo deste trabalho foi avaliar a produtividade, a área foliar, a condutância estomática, a fotossíntese, a transpiração e a fração de água transpirável no solo crítica (FATSc) de genótipos de milho híbrido e crioulo, em função do deficit hídrico caracterizado pela FATS. Foram realizados dois experimentos, nos anos agrícolas de 2015/2016 e 2016/2017: um a campo e outro em casa de vegetação. Os seguintes genótipos foram avaliados em sistema irrigado e não irrigado: os crioulos Cinquentinha e Bico de Ouro e a cultivar melhorada AS 1573PRO. A produtividade a campo é maior para 'AS 1573PRO', seguida por Bico de Ouro e Cinquentinha, em ambos os anos de avalição. O deficit hídrico reduz a abertura estomática, a fotossíntese e a taxa de transpiração, o que resulta no fechamento total dos estômatos de 'AS 1573PRO' e Bico de Ouro, e no fechamento parcial dos de Cinquentinha. Houve redução da área foliar de 'AS 1573PRO', Bico de Ouro e Cinquentinha sob deficit hídrico durante o período reprodutivo. No primeiro ano agrícola sob condições de deficit hídrico, 'AS 1573PRO' e Cinquentinha mostram alta tolerância ao deficit hídrico com FTSWc de 0,71, e 'AS 1573PRO' também mostra a maior tolerância no segundo ano agrícola com FTSWc de 0,73. Além disso, Bico de Ouro apresenta sensibilidade ao deficit hídrico nos dois anos agrícolas.

Abstract The objective of this work was to evaluate the yield, leaf area, stomatal conductance, photosynthesis, transpiration, and critical fraction of transpirable soil water (FTSWc) of hybrid and landrace corn (Zea mays) genotypes, as affected by the water deficit characterized by the FTSW. Two experiments were carried out in the 2015/2016 and 2016/2017 crop years: one in the field and the other in a greenhouse. The following genotypes were evaluated in irrigated and nonirrigated systems: the Cinquentinha and Bico de Ouro landraces and the AS 1573PRO improved cultivar. Yield in the field was higher for 'AS 1573PRO', followed by Bico de Ouro and Cinquentinha in both evaluation years. Water deficit reduces stomatal opening, photosynthesis, and transpiration rate, resulting in the total closure of the stomata of 'AS 1573PRO' and Bico de Ouro, and in the partial closure of those of Cinquentinha. There was a reduction in the leaf area of 'AS 1573PRO', Bico de Ouro, and Cinquentinha under water deficit during the reproductive period. In the first crop year under water deficit conditions, 'AS 1573PRO' and Cinquentinha show a high tolerance to water deficit with a FTSWc of 0.71, and 'AS 1573PRO' also shows the highest tolerance in the second crop year with a FTSWc of 0.73. Moreover, Bico de Ouro is sensitive to water deficit in the two crop years.

RESUMO: Eugenia involucrata DC. é uma espécie florestal com elevado potencial ambiental e econômico. O presente trabalho teve por objetivo quantificar a variabilidade e analisar a estruturação genética em três fragmentos naturais localizados na região central do estado do Rio Grande do Sul, Brasil. Com o emprego de quatro locos microssatélites desenvolvidos para a espécie congênere Eugenia uniflora e usando-se o software GenAlEx 6.5, foram estimados parâmetros de variabilidade genética, para cada loco, e sua partição entre e dentro dos fragmentos. Foram observados altos índices de variabilidade genética (3,67 alelos por loco; HO = 0,815; HE = 0,625; FIS = -0,294), com a maior proporção (93%) distribuída dentro dos fragmentos, sugerindo que os indivíduos estudados são provenientes de uma única população original. O fluxo gênico foi elevado entre os fragmentos, variando de 2,35 a 4,56 migrantes por geração, resultando em baixo índice de diferenciação genética (FST), entre 0,052 a 0,096. Os fragmentos estudados apresentam elevada variabilidade genética, a maior parte distribuída dentro dos próprios remanescentes, e baixa diferenciação genética. Os resultados observados têm repercussões no planejamento de coleta de germoplasma com adaptação local para programas de restauração florestal, assim evitando a implantação de populações com depressão exogâmica.

ABSCTRACT: Eugenia involucrata DC. is a forest species with high environmental and economic potential. The objective of this study was to quantify the genetic variability and analyzed the genetic structure of three natural fragments located in the central region of the Rio Grande do Sul state, Brazil. We used four microsatellite loci developed for the congener species Eugenia uniflora and using GenAlEx 6.5 software, parameters of genetic variability and its partition among and within fragments were estimated for each locus. We observed high levels of genetic variability (3.67 alleles per locus; HO = 0.815; HE = 0.625; FIS = −0.294), most of which (93%) were distributed within the fragments, suggesting that these individuals came from a single original population. Gene flow between fragments was high (2.35 to 4.56 migrants per generation), resulting in low genetic differentiation indexes (FST values ranging from 0.052 to 0.096). The fragments showed high genetic variability, distributed within the remnants themselves, and low genetic differentiation. Our results have repercussions for planning locally adapted germplasm collections for forest restoration programs, thereby avoiding the implantation of populations with an exogamous depression.

Abstract Seminal Luehea divaricate seedling production has been limited by the low availability of seeds with appropriate physiological and health atributes. Studies regarding the vegetative propagation of Luehea divaricata Mart. & Zucc showed that the species has a potential multiplication through methods alternative to seeds. The aim of this study was to evaluate the response of cultures initiated from Luehea divaricata Mart. & Zucc. epicotyl, to stimuli from different sources and concentrations of cytokinin in vitro multiplication. Epicotyls containing one or two axillary buds were used, in which treatments were 0, 5, 10 or 15μM of cytokine: 2-isopentenyladenine (2iP), 6-benzylaminopurine (BA), Kinetin (KIN) and Thidiazuron (TDZ) sources added to the nutrient broth medium, distributed in a completely randomized design. At 45 days of culture, there was an interaction between the sources and the cytokinin concentrations used, affecting the percentage of in vitro establishment (86.2%), number of buds (6.82), number of shoots (2.48), number of leaves (8.5), while the percentage of callus formation was influenced by the concentrations of cytokinins (48%). It was concluded that the in vitro multiplication of cultures initiated from epicotyls of Luehea divaricata Mart. & Zucc, the use of cytokinins 6-benzylaminopurine (BAP), 2-isopentenyladenine (2iP), Kinetin (KIN) and Thidiazuron (TDZ) is dispensable. In the absence of cytokinins nutrient broth medium, better responses were observed in relation to in vitro survival and establishment, bud number and number of leaves formed and BAP, 2ip, KIN and TDZ at concentrations between 5 and 15μM, promote callus formation.

Resumo A produção de mudas de Luehea divaricata (açoita-cavalo), pela via seminal tem sido limitada pela reduzida disponibilidade de sementes com adequada qualidade fisiológica e sanitária. Estudos relacionados à propagação vegetativa de açoita-cavalo, usando diferentes técnicas, apontaram que a espécie apresenta potencialidade de multiplicação por meio de métodos alternativos à via sementes. O objetivo do presente estudo foi avaliar a resposta de culturas iniciadas a partir de epicótilos de açoita-cavalo, aos estímulos de diferentes fontes e concentrações de citocinina na multiplicação in vitro. Foram utilizados epicótilos contendo uma ou duas gemas axilares, em que os tratamentos consistiram de 0; 5; 10 ou 15μM das fontes de citocinina: 2-Isopenteniladenina (2iP), 6-Benzilaminopurina (BAP), Cinetina (CIN) e Thidiazuron (TDZ), acrescidos ao meio nutritivo MS, distribuídos em delineamento inteiramente casualizado. Aos 45 dias de cultivo, foi verificado interação entre as fontes e concentrações de citocinina usadas, afetando a porcentagem de estabelecimento in vitro (86,2%), número de gemas (6,82), número de ápices caulinares (2,48), número de folhas (8,5), enquanto a porcentagem de formação de calos foi influenciada pelas concentrações das citocininas (48%). Conclui-se que na multiplicação in vitro de culturas iniciadas a partir de epicótilos de açoita-cavalo, é dispensável o uso das citocininas 6-Benzilaminopurina (BAP), 2-Isopenteniladenina (2iP), Cinetina (CIN) e Thidiazuron (TDZ). Na ausência das citocininas no meio nutritivo MS observa-se melhores respostas em relação à sobrevivência e estabelecimento, número de gemas e número de folhas formadas e, BAP, 2ip, CIN e TDZ, nas concentrações entre 5 a 15µM, promovem a formação de calos.

Resumo Eugenia involucrata é uma espécie florestal nativa do Brasil com grande potencial para uso madeireiro, frutícola e medicinal. O presente estudo objetivou avaliar a influência de fitorreguladores e da luminosidade sobre a calogênese em discos foliares de Eugenia involucrata. Foi conduzido um experimento bifatorial (2x5), cujos tratamentos consistiram na combinação da ausência ou presença de luz durante o cultivo e de cinco diferentes empregos de fitorreguladores: ANA, 2,4-D, BAP e as combinações ANA + BAP e 2,4-D + BAP, todos a 5 μM, em meio nutritivo MS. Após 45 dias de cultivo in vitro foi observado que a ausência de luz durante o período de cultivo reduz a oxidação fenólica favorecendo, assim, a calogênese , especialmente na presença de ANA e das combinações ANA + BAP e 2,4-D + BAP. O uso de 2,4-D e de BAP, isoladamente, não é favorável à calogênese em discos foliares de Eugenia involucrata.

Abstract Eugenia involucrata is a native forest species from Brazil with great potential for timber, fruit and medical purpouses. This study aimed to evaluate the influence of growth regulators and the effect of light on calli induction from leaves disks of Eugenia involucrata. A bifactorial experiment (2x5) was conducted, in which the treatments consisted in the combinations of absence or presence of light during cultivation and five different uses of phytoregulators: NAA, 2,4-D, BAP and combinations of NAA and BAP, 2,4-D and BAP, all at 5 μM, in the nutritious medium MS. After 45 days of in vitro cultivation, it was observed that the absence of light during the cultivation period reduced phenolic oxidation, thus stimulated calogenesis, mainly in the presence of ANA and the combinations NAA + BAP and 2,4-D + BAP. The use of 2,4-D and BAP, on isolated way, did not favor calli formation in leaves disks of Eugenia involucrata.

Abstract The objective of this study was to evaluate the effect of sucrose and substrates on the acclimatization of micropropagated Luehea divaricata plants. First, the effect of sucrose on in vitro growth and development of nodal segments in Woody Plant Medium reduced to its half concentration was tested. After that, these shoots were then acclimatized and the combined effect of sucrose, as previously described, plus the commercial substrates vermiculite, MecPlant® or H-decker® were tested. In the in vitro culture, root and leaf formation were superior (44%, 8.44 leaves) with 20 g L-1 sucrose, and then the presence of sucrose continued to be more efficient in the acclimatization with the MecPlant® or H-decker® commercial substrates. Sucrose at 20 g L-1 is more efficient for in vitro leaf and root formation, and the MecPlant® or H-decker® substrates may be used in acclimatization.

Resumo Luehea divaricata, conhecida popularmente como açoita-cavalo, é uma espécie florestal nativa da Mata Atlântica muito utilizada para a recuperação de áreas degradadas. Sua madeira pode ser empregada para as mais diversas finalidades, o que contribuiu para a redução de suas populações naturais e ocasionou dificuldades na obtenção de sementes com qualidade genética, fisiológica e sanitária para uso na produção de mudas. Sendo assim, a micropropagação é uma alternativa para a produção de mudas da espécie para uso em projetos ambientais. Com isso, o presente trabalho teve como objetivo otimizar o processo de rizogênese in vitro e, para isso, foram avaliadas, inicialmente, diferentes concentrações de sais do meio nutritivo WPM. Em seguida, foram estudados os efeitos do ácido indolbutírico (AIB), adicionado ao meio em tratamento “pulse” por 15 dias, e do ácido naftalenoacético (ANA), na rizogênese, em ambos os casos em cultivo em meio WPM cuja concentração de sais foi reduzida à metade (WPM/2). Por fim, também foi analisado o efeito da combinação de volumes de vermiculita com WPM/2. Os resultados indicaram que o meio WPM/2 apresentou resultados promissores para o estabelecimento (98%) in vitro e, no que diz respeito à formação de raízes adventícias primárias, após 45 dias de cultivo in vitro observaram-se as maiores médias (40,52%), independentemente da concentração de sais do meio. O tratamento “pulse” após 30 dias de cultivo in vitro, independentemente da concentração de AIB, resultou em uma média de 25,18% de formação de raízes adventícias primárias. As combinações de 20 mL + 15 cm3, 20 mL + 30 cm3 e 30 mL + 30 cm3 de meio nutritivo e de vermiculita, respectivamente, foram as mais favoráveis para a formação de raízes adventícias laterais de segunda ordem, proporcionando médias entre 38 e 49,5% após 45 dias de cultivo in vitro. Para otimizar o processo de rizogênese de Luehea divaricata é indicado o cultivo in vitro por 45 dias em meio nutritivo WPM/2, combinado com vermiculita, prescindindo da adição de auxinas.

Abstract Luehea divaricata is a native forest species of the Atlantic Rainforest biome widely used for the recovery of degraded areas. Its wood can be used for the most diverse purposes, which has contributed to a reduction in its natural populations and is causing difficulties to find seeds with genetic, physiological and sanitary quality for using in the seedling production. Therefore, micropropagation is an alternative with the potential for producing seedlings to use in environmental projects. The objective of this work was to optimize the in vitro rhizogenesis processes, in which different concentrations of salts of the WPM nutritive medium were initially evaluated. Next, Indolbutyric Acid (IBA) was added to the medium as the “pulse” treatment for 15 days, and Naphthaleneacetic Acid (NAA) in both cases to the in vitro culture in WPM nutritive medium was reduced to half of its initial concentration (WPM/2) and the rhizogenesis effects were analyzed. Finally, the effect of combining vermiculite volumes with WPM/2 was also analyzed. The results showed that the WPM/2 medium produced the most promising results of the in vitro establishment (98%), and the highest average (40.52%) regarding the formation of primary adventitious roots after 45 days of in vitro culture was observed regardless the concentration of salts in the medium. The “pulse” treatment after 30 days of in vitro culture, regardless of IBA concentration, resulted in an average of only 25.18% of primary adventitious root formation. The combinations of 20 mL + 15 cm3, 20 mL + 30 cm3 and 30 mL + 30 cm3 of nutritive medium and vermiculite, respectively, were the most favorable for forming second order lateral adventitious roots, providing averages between 38 and 49.5% after 45 days of in vitro culture. Therefore, in order to optimize the rhizogenesis process of Luehea divaricata, it is indicated to grow the in vitro culture for 45 days in WPM/2 nutritive medium combined with vermiculite without the addition of auxins.

Abstract Nectandra megapotamica (Spreng.) Mez. it is a native tree species of the Atlantic Forest, commonly known as canela-preta. The species has some anti-inflammatory, antitumor and antirheumatic properties among others. In this work the use of frozen plant material for microscopy analysis was tested. In addition, the leaf morpho-anatomy of the species was characterized which allowed to perform a structural description and to identify structures of secretion and storage of essential oil. The plant material was prepared for analyzes in optical, fluorescence and scanning electron microscopy. The leaf anatomy shows glabrous epidermis, unistratified, paracytic stomata, absence of trichomes, polyhedral epidermal cells. Some typical family characteristics were observed as a closed arc-shaped bicollateral bundle vascular system and dorsiventral mesophyll. The structures of secretion and storage of essential oil were identified as secretory cavities.

RESUMO: O objetivo do presente trabalho foi avaliar o efeito de diferentes concentrações do ácido indolbutírico (AIB) em dois períodos de cultivo em casa de vegetação sobre o enraizamento de miniestacas de Luehea divaricata. As miniestacas foram imersas por 10s em solução hidroetanólica contendo AIB. Todas as miniestacas sobreviveram tanto após 30 como 60 dias de cultivo. A formação de raízes aos 30 dias com 1000 mg L-1 de AIB foi de 91,7%, mesma média observada com 4000 mg L-1. Em relação ao número de raízes, novamente a concentração 1000 mg L-1destacou-se em relação às demais concentrações, e já aos 30 dias de cultivo houve 8,42 raízes por miniestaca. Aos 30 dias de cultivo, a formação e o número de raízes na presença de 1000 mg L-1 de AIB em tratamento “pulse” já produz resultados satisfatórios, permitindo que as plantas permaneçam menor tempo em casa de vegetação utilizando-se uma concentração reduzida de auxina, comparativamente àquelas que foram testadas. No entanto, para obter maiores médias de formação de raízes secundárias, comprimento das raízes e número de folhas é necessário prolongar o cultivo pelo período de 60 dias.

ABSTRACT: The objective of the present research was to evaluate the effect of different concentrations of indolebutyric acid (IBA) on the rooting of Luehea divaricata minicuttings under two different cultivation periods in a greenhouse environment. The minicuttings were immersed in a hydroethanolic solution containing IBA. All minicuttings survived after 30 and 60 days of cultivation. Root formation at 30 days of cultivation with 1000 mg L-1 of IBA was 91.7%, the same rate as that observed with 4000 mg L-1. At the 1000 mg L-1 concentration, the number of roots was the greatest among all treatments, with 8.42 roots per minicutting after 30 days of cultivation. After 30 days of cultivation, the formation and number of roots with the use of 1000 mg L-1 of IBA in the “pulse” treatment produced the best outcome results, allowing the plants to spend less time in a greenhouse at a reduced concentration of auxin when compared with other treatments. However, to obtain higher averages of secondary root formation, root length, and number of leaves, it is necessary to increase the cultivation period to 60 days.

RESUMO: O fluxo gênico, cuja efetividade é função do modelo e da taxa, assume especial importância na conservação de recursos genéticos por permitir a conectividade de populações isoladas geograficamente, sujeitas à redução da variabilidade genética. O entendimento de como o fluxo gênico ocorre pode contribuir no planejamento de ações para a conservação e na seleção de populações prioritárias para uma eventual intervenção. Programas de simulação permitem inferir sobre eventos passados, a partir de dados atuais ou prever fenômenos futuros sob cenários genéticos reais. Fenômenos adversos podem ser previstos e medidas podem ser tomadas para contorná-los. O objetivo deste estudo foi identificar o modelo e a taxa de fluxo gênico que melhor explicam a estrutura genética de oito fragmentos da espécie arbórea florestal Cabralea canjerana, em desenvolvimento na região brasileira do bioma Mata Atlântica. Foram realizadas simulações com o programa EASYPOP usando dados de marcadores microssatélites obtidos por Melo e colaboradores, em 2012, 2014 e 2016, sendo testados cinco modelos e nove taxas de migração, selecionando-se o modelo que apresentou os valores mais próximos daqueles que foram publicados. Os critérios usados para a seleção do modelo foram a heterozigosidade observada e esperada e as estatísticas F de Wright obtidas nas simulações. O modelo de fluxo gênico entre os fragmentos foi o de isolamento por distância a uma taxa de 0.1. Foram observados elevados índices de diferenciação genética entre os fragmentos em decorrência do seu isolamento reprodutivo. Desse modo, sugere-se a construção de corredores ecológicos com vistas a conectar fragmentos distantes e, desta forma, permitir a homogeneização das frequências alélicas por meio do fluxo gênico.

ABSTRACT: Gene flow is important for the conservation of genetic resources to allow connectivity of geographically isolated populations and which genetic variability is reduced. Gene movement is a function of flow rate and model. Understanding how gene flow occurs can contribute to the conservation and selection of priority populations that could benefit from an eventual intervention. Simulation softwares allow making inferences about past events based on current datasets or predict future phenomena under real genetic scenarios. Adverse phenomena can be predicted and actions can be taken to avoid them. The aim of this study was to identify a model and the gene flow rates that could explain genetic structure of eight forest fragments of Cabralea canjerana in development in the Brazilian Atlantic Rainforest. To do this, simulations were performed with the EASYPOP software using a microsatellite marker dataset obtained for the species by Melo and collaborators, in 2012, 2014 and 2016. We tested five models and nine migration rates and we selected the model that produced values closer to those previously obtained for them. Criteria used for selection were the observed and expected heterozygosity and the Wright’s F Statistics obtained in the simulations. The gene flow model selected was the isolation by distance model that used a rate of 0.1. We observed high levels of genetic differentiation among the fragments as result of their reproductive isolation. To allow homogenization of the allelic frequencies through gene flow, the solution would be to create ecological corridors with the aim of connecting distant fragments.

ABSTRACT The cultivation of yerba-mate (Ilex paraguariensis) has been intensified in the State of Rio Grande do Sul, as result of the valuation of the price paid to the producer. However, studies related to Fusarium pathosystem vs. yerba-mate are still insufficient, so that many producers have faced significant losses in herbal production due to the occurrence of the roots rotting. Considering the above, the objectives of this study were: a) morphologically characterize the Fusarium spp. isolates collected in sick plants of yerba-mate; b) select efficient morphological characters on separating the Fusarium spp. isolates in similarity groups; c) identify the Fusarium spp. isolates to species level through the sequencing of the genomic region of elongation factor 1-α (TEF-1α); and d) testing the pathogenicity of the Fusarium spp. isolates selected based on the morphological characterization. For such, collections for the pathogen isolates were made in five cities and the collection points were georeferenced. Thirty-nine isolates were morphologically characterized by variables as mycelial growth, sporulation, macroconidia length and width, microconid format, colonies pigmentation and formation of chlamydospore, and tested for pathogenicity by substrate inoculation. The variables used in the morphological characterization were efficient in discriminating the isolates in seven groups, especially length of macronidia associated to sporulation. Seven pathogenic isolates of Fusarium spp. were identified, also through molecular sequencing of the TEF-1α gene region. The sequencing of the TEF-1α region consolidated the identification of pathogenic isolates as F. solani and F. oxysporum.