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Camu-camu is an native species in domestication processes. Therefore, studies related to the root system are necessary to evaluate the best cultivation practices for an orchard. Two trials were conducted, one with nitrogen (N) and the other with potassium (K), at doses of 0, 40, 80, 160, and 320 kg·ha–1. Root distribution was determined using nondestructive analyses in which two-dimensional (2D) root images were obtained from trenches under the plants’ canopy. Variables included width (measured in cubic millimeters), area (measured in square millimeters), and length (measured in millimeters, and were analyzed using Safira software (version 2010, Embrapa, Brazil). To have better spatial visualization of variable distribution in the soil profile, data were analyzed using the ordinary kriging technique with the geoR software package and R software (version 2016). Both N and K doses influenced positively the camu-camu root system with regard to length, volume, and area. Better root distribution was verified with 80 kg·ha−1 N and 160 kg·ha−1 K doses. The nondestructive analysis via 2D images allowed sound characterization of root spatial distribution.

The cacari ( Myrciaria dubia ) is a native fruit tree from Amazon with high concentrations of vitamin C. This study aimed to adjust a culture medium that meets the nutritional needs for the in vitro development of cacari, evaluating the effect of different concentrations and nutritive culture media, antioxidant, and levels of agar and pH. Three experiments were carried out in a completely randomized design: 1 - woody plant medium (WPM), Murashige and Skoog (MS) and Juan, Antonio, Diva and Silvia medium (JADS) nutritive media with 25, 50, 75 and 100% concentrations; 2 - pH (3.7, 4.7, 5.7 and 6.7) and agar concentrations (0, 3.5, 7.0 and 10.5 g.L -1 ); 3 - Antioxidants [( ascorbic acid (AA), citric acid (CA), polyvinylpyrrolidone (PVP)] and concentrations (0, 100, 200, 300 mg.L -1 ) on the control of phenolic oxidation of stem segments. After collection, the explants were disinfested in a laminar flow chamber, dipping in 70% ethanol for 3 min and 1.5% sodium hypochlorite for 12 min, followed by three washes in distilled and autoclaved water. After disinfestation, the explants were inoculated in 15 × 125 mm test tubes containing 30 mL culture medium, according to each experiment and their respective treatments. After 90 days, the number and length of sprouts (cm) and the oxidation were evaluated. The best results were obtained using the WPM medium at a concentration of 100% with 7 g.L -1 agar, and pH adjusted to 5.7. The use of antioxidants in the tested conditions did not contribute to decrease in oxidation in explants, indicating that there is no need of adding them into the culture medium. Keywords: Camu-camu, in vitro culture, Myrciaria dubia , organogenesis

In the Brazilian Amazon is significant diversity of fruit species, the agronomic characteristics of which are still little studied. The objective of this study was to evaluate the influence of tegument coloration on germination and vigor of camu-camu seeds. The seeds were obtained from ripe and healthy fruits coming from population of the Urubu River in Roraima and were classified visually according to the tegument coloration of green, red and brown color. 200 seeds for each class of colors were utilized, evaluating the following biometric characters: length, breadth, thickness and individual mass, obtained with the aid of a digital caliper and precision balance. The experimental design utilized was the completely randomized with three treatments and 10 replications of 20 seeds. The highest means of mass and volume were obtained from brown and red seeds. The brown seeds produce higher content of root dry mass than both the green and red seeds. The physiological quality of camu-camu seeds of the Urubu River is associated with tegument coloration. Seeds with brown tegument have better development, greater growth of seedlings with greater accumulation of dry matter both in the roots and shoots.

The açaí palm (Euterpe oleracea Mart.) is a tree native to the Amazonia. In some states in the region, growth of the planted area has been observed, but the difficulty in obtaining substrates which are viable for the production of seedlings is high. It was intended in a first step to evaluate the effect of seed size and substrates upon germination and in the second step, to evaluate the initial growth of seedlings of E. oleracea on different substrates. The experimental design was a completely randomized design in 2 x 2 factorial scheme with four replications at 100 seeds. Germination percentage, percentage of abnormal seedlings, shoot and root length and dry weight of the seedlings were evaluated after 70 days. In the second step, completely randomized design in 9 x 6 factorial scheme with five replications with four seedlings/ plot was utilized. At 60, 90 , 120 , 150 , 180 and 210 days after transplanting, shoot height and diameter of the stem of the plant were assessed, number of leaves were determinate at 90, 120 , 150, 180 and 210 dat and at 210 dat, determinations of dry weight of the shoot and root system were conducted. These samples were put in an oven with forced air circulation at 60 ºC for 72 hours. Açaí seeds considered large present greater germination percent as compared with small seeds and the substrate sand provides greater percentage of seed germination. The substrates composed of 75% (soil+sand) + 25% manure and with 75% (soil+sand) + 25% carbonized rice husk present better development of açai seedlings.

Camu-camu (Myrciaria dubia) is a fruit species native to the Amazon and its economic importance is proven because the fruit contains high content of ascorbic acid. The objective of this work was to evaluate the germination and vigor of seedlings obtained from seeds of different sizes of two camu-camu populations. The experimental design was completely randomized in a factorial scheme of 2 x 3 (two provenances river Anauá and river Urubu and three seed sizes, small, medium and large) with 5 replicates of 20 seeds per plot. The seeds of the origin of the Anauá river presented higher mass (1.46 g) compared to the origin of the Urubu river (0.78 g). The speed and emergence of seed germination presented better values for the population of the Anauá river, justifying the adoption of choice of origin for the formation of seedlings. For root length, dry shoot mass and dry mass of the root system, the seeds classified as medium and large originated from the Anauá river presented higher values. The size of the seeds is an important character to be used in the production of Myrciaria dubia seedlings. The seeds of the origin of the Anauá river are potentially more vigorous are indicate for the production of camu-camu (Myrciaria dubia) seedlings. O camu-camu (Myrciaria dubia) é uma espécie frutífera nativa da Amazônia e sua importância econômica é comprovada devido ao fruto conter elevado teor de ácido ascórbico. O trabalho foi realizado com objetivo de avaliar a germinação e vigor de plântulas obtidas de sementes de diferentes tamanhos de duas populações de camu-camu. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial de 2 x 3 (duas procedências: rio Anauá e rio Urubu e três tamanhos de sementes: pequeno, médio e grande) com 5 repetições de 20 sementes por parcela. As sementes da procedência do rio Anauá, apresentaram maior massa (1,46 g) comparada com a procedência do rio Urubu (0,78 g). O percentual de emergência e velocidade de emergência de plântulas apresentaram melhores valores para a população do rio Anauá, justificando-se a adoção de escolha de procedência para a formação de mudas. Para comprimento do sistema radicular, massa seca da parte aérea e massa seca do sistema radicular, as sementes classificadas como média e grande oriundas do rio Anauá apresentaram maiores valores. As classes de massa das sementes apresentam um caractere importante para ser utilizado na produção de mudas de Myrciaria dubia. As sementes da procedência do rio Anauá são potencialmente mais vigorosas sendo indicadas para a produção de mudas de camu-camu (Myrciaria dubia).

O cupuaçu pode ser propagado por via sexuada ou assexuada, sendo a via seminífera o processo mais utilizado. Dessa forma, ambientes apropriados para a produção de mudas propiciam melhores condições para o crescimento inicial em campo, colaborando para o aumento da homogeneidade, sanidade e redução da mortalidade de plantas no momento do plantio. Assim, fatores como luz e tipo de substrato são importantes para a germinação de sementes e emergência inicial de plantas. Nesse contexto, objetivou-se com o presente trabalho avaliar o efeito de diferentes substratos, bem como a influência do sombreamento na emergência e no crescimento inicial de plântulas de cupuaçu. O experimento foi conduzido na Embrapa Roraima, utilizando-se delineamento inteiramente casualizado, em esquema fatorial 3 x 7, constituídos de diferentes ambientes (canteiro sem cobertura, canteiro com cobertura tipo sombrite de 50% de luminosidade e canteiro com cobertura plástica transparente de 100 micras), combinados com diferentes substratos (areia, solo, vivatto®, serragem, areia+solo, areia+solo+vivatto® e areia+solo+serragem). Após a semeadura, avaliou-se a porcentagem de emergência e o índice de velocidade de emergência no intervalo de cinco dias, quando, ao final dos 50 dias, avaliou-se o comprimento da parte aérea, o número de folhas, a área foliar, o comprimento do sistema radicular, o diâmetro do caule, a massa seca da parte aérea e do sistema radicular. Observou-se que maior porcentagem de emergência, IVE e desenvolvimento inicial de plântulas de cupuaçuzeiro são obtidos ao se utilizar substrato constituído por areia+solo+serragem. O ambiente com sombreamento de 50% de luminosidade proporciona maior porcentagem de emergência, IVE, diâmetro do colo e massa seca do sistema radicular.

Similarly to most breeding programs of native species, camu-camu (Myrciaria dubia (Kunt) McVaugh) improvement is also restricted, due to the scarcity of research results. In this situation, the prospection, collection and conservation of germplasm in genebanks ensure successful selection and breeding studies of the species. In this sense, the purpose of this study was the intraspecific characterization of the biometric variability in fruits of native camu-camu populations of the State of Roraima, in the northern Amazon region. Of 16 populations, 247 sub-samples were evaluated. Analyses were performed with the multivariate technique of principal components and hierarchical clustering, to determine the variables with highest intraspecific variability for the studied traits. The populations found in the lower Rio Branco region performed best for the studied traits, indicating the great potential of the region as a reservoir of promising subsamples for future breeding programs of the species in the northern Amazon. Resumo Como a maioria dos programas de melhoramento de espécies nativas, o camu-camu (Myrciaria dubia (Kunt) McVaugh), apresenta limitações pelas escassas experiências de pesquisas. Dessa forma, a prospecção, coleção e conservação através dos Bancos de Germoplasma são uma garantia para a realização de trabalhos de seleção e melhoramento da espécie. Neste sentido, objetivou-se com o presente trabalho realizar a caracterização intraespecífica da variabilidade biométrica em frutos de populações nativas de camu-camu, prospectados no estado de Roraima, Amazônia Setentrional. Foram avaliados 247 subamostras provenientes de 16 populações. As análises foram realizadas com auxilio da técnica multivariada de componentes principais e de agrupamento hierárquico. As análises permitiram determinar as variáveis que aportaram à maior variabilidade intraespecífica nas características avaliadas. As populações oriundas da região do baixo rio Branco apresentaram os maiores atributos nas características avaliadas, representando uma região com grande potencialidade na obtenção de subamostras promissores para futuros planos de melhoramento da espécie na Amazônia Setentrional.

Uma das tendências do mundo moderno é a orientação ao consumo de produtos naturais com alto valor nutritivo e vitamínico. O camu-camu é uma fruteira nativa da Amazônia, que chama a atenção pelo alto conteúdo de vitamina C (6,116 mg/100 g de polpa). La espécie está em processo de domesticação, pelo qual se vem desenvolvendo modelos tecnológicos para lograr seu estabelecimento em condições de terra firme. Com o objetivo de avaliar diferentes doses de potássio aplicadas via fertirrigação no desenvolvimento inicial de plantas de camu-camu, conduziu-se um experimento no centro experimental Agua Boa da Embrapa Roraima. Utilizou-se o delineamento experimental em blocos casualizados com 5 tratamentos 0; 40; 80; 120 e 160 kg ha-1 de K, aplicado em forma de KCl, seis repetições e sete plantas por parcela experimental. O experimento foi conduzido durante 270 dias após o transplantío (DAT). A cada 30 dias foram avaliados o diâmetro do coleto (mm) e altura de planta (cm); logo a cada 90 dias foram avaliados o número de ramos e comprimento total de ramos (cm). Ao final do experimento foi avaliado a massa seca das folhas, massa seca dos ramos, massa seca do sistema radicular, massa seca total (g) e o índice de qualidade de Dickson. Diante dos resultados, verificou-se que a fertilização potássica na dose 160 kg ha-1 de K O via fertirrigação 2 proporcionou maior crescimento e qualidade de plantas camu-camu no primeiro ano de adubação em condições de terra firme.

Camu-camu is an Amazonian species with fruits that have high a concentration of ascorbic acid, a feature of interest to the food and pharmacological industries. However, for cultivation, studies are needed on seedling production and the use of alternative substrates. The objective of the present study was to develop camu-camu seedlings using different alternative substrates. For seedlings formation, seeds were removed from fruits collected from plants on the Urubu River in Boa Vista-RR, Brazil. A completely randomized experimental design was used, with ten substrates, five replications and five plants per replication. The treatments consisted of: [T1 - Soil; T2 - standard substrate: 3 parts sand soil + 1, T3 - commercial substrate: organoamazon®, T4 – standard substrate +75 % manure (E), T5 - standard substrate +50 % E; T6 - standard substrate + 25 % E, T7 - standard substrate +75 % rice hulls (C), T8 - standard substrate + 50% C; standard substrate T9 = 25% + C; T10 standard substrate +25% E + 25 % C]. The following characteristics were evaluated: plant height (cm), diameter (mm), shoot and root dry matter (g), root length (cm) and number of leaves. The substrate consisting of standard soil and sand at the ratio 3:1 gave favorable results for all the characteristics. Substrates with increasing proportions of rice hulls and manure did not improve the camu-camu tree seedling development.

The objective in the present work was to evaluate the genetic diversity among 15 indigenous populations of camu-camu plants, identifying important characteristics in the evaluation of genetic divergence, based on the initial characteristics of the seedlings. Seeds extracted from fruits deriving from fifteen indigenous populations of camu-camu were collected. The experimental design was entirely random, with fifteen treatments (populations), and fifteen repetitions (each sub-sample), considering 30 seeds per subsample as an experimental unit. At 40 days after sowing the following were evaluated: the percentage of emergence, the index of emergence velocity, the average time of germination, the height of the seedling and the number of leaves. The data obtained was submitted to variance analysis, and the averages were grouped by the Scott and Knott (1974) test. The genetic diversity was studied according to the Tocher grouping method, based on the Mahalanobis distance (D2ii) and canonical variables. The fifteen populations are divergent among themselves and the Rio Branco Estirão do Veado, Rio Branco Onofre and Igarapé Agua Boa populations are indicated to have hybridization with other populations due to the high divergence, as well as the rates of emergence and vigor of the seedlings. The height of the seedlings, percentage and speed of emergence, are those that most indicate genetic divergence. The measuring techniques of genetic divergence, canonical variables Mahalanobis distances are useful and corroborating in the evaluation of genetic divergence of the camu-camu plant.