Resumo As regiões tradicionais de produção de pêssego apresentam frio adequado para a quebra de dormência das gemas de forma satisfatória, nas cultivares localmente desenvolvidas. No entanto, considerando a expansão dos pomares em áreas peachde inverno ameno e as tendências globais esperadas para condições mais quentes, o desenvolvimento local de cultivares tornou-se relevante. Com base nisso, este estudo propôs-se a avaliar o desempenho de 33 cultivares e seleções de pessegueiro e nectarineiraem clima de inverno ameno. Características associadas ao desenvolvimento vegetativo,fenologia, produtividade e características dos frutos foram medidas em nove safras; e os dados, analisados por análise de variância multivariada. Foram observadas correlaçõessignificativas entre as características. Os testes de Pillai e F apresentaram resultadossignificativos, destacando a presença de diferenças entre cultivares para quase todas as características.Os genótipos de pessegueiro e de nectarineira apresentaram diversidade genética que pode ser acessada para uso como cultivares, ou parentais para cruzamentos. As cultivares ‘IACAurora 1’, ‘IAC Aurora 2’, ‘IAC Centenário’, ‘IAC Douradão’, ‘IAC Jóia4’, ‘IACOuromel 3’, ‘IAC Régis’,‘Diamante’, ‘Eldorado’, ‘FlordaPrince’, ‘Premier’ e ‘Tropic Beauty’apresentaram os melhores resultados. Um grande número de seleções apresentou resultados promissores, destacando-`se ‘IAC 680-177’, ‘IAC 1085-27’, ‘IAC 785-9’, ‘IAC 2982-31’, ‘IAC 4682-45’ e‘IAC 6882-84’.

Abstract Traditional peach production regions provide adequate chill for satisfactorily bud’s flower break dormancy, in cultivars there developed. However, considering the expansion of the orchards in mild winter areas and the expected global trends to warmer conditions, the local development of cultivars became relevant. Based on this background, this study proposed to evaluate the performance of 33 peach and nectarine cultivars and selections in mild winter climate. Features associated to the vegetative development, phenology, productivity and fruit characteristics were measured in nine seasons, and the data analyzed by multivariate analysis of variance. Significant correlations between features were remarked. The Pillai and F tests presented significant results, highlighting significant differences among cultivars for almost all features. Peach and nectarine genotypes showed genetic diversity that may be accessed for use as cultivars, or parental for crosses. ‘IAC Aurora 1’, ‘IAC Aurora 2’, ‘IAC Centenário’, ‘IAC Douradão’, ‘IAC Jóia4’, ‘IAC Ouromel 3’, ‘IAC Régis’, ‘Diamante’, ‘Eldorado’, ‘FlordaPrince’, ‘Premier’ and ‘Tropic Beauty’ were the cultivars with the best results. A large number of selections showed promising results, emphasizing, the ‘IAC 680-177’, ‘IAC 1085-27’, ‘IAC 785-9’, ‘IAC 2982-31’, ‘IAC 4682-45’and ‘IAC 6882-84’.

Resumo: O objetivo deste estudo foi avaliar a diversidade genética entre genótipos, com base nas características físicas, químicas e físico-químicas do araçá-boi em condições tropicais.O experimento foi realizado na Universidade Federal de Roraima, no município de Boa Vista, Roraima, Brasil. Os genótipos foram obtidos na geração F1, atravésde polinização aberta. Foram avaliadas 12 plantas, sendo coletados 10 frutos por planta.Foram avaliadas as características físicas e físico-químicas dos frutos: massa fresca, comprimento e diâmetro dos frutos, rendimento de polpa, firmeza, massa de polpa, casca e sementes,número de sementes, sólidos solúveis, acidez titulável, pH, relação SS/AT e vitamina Cde frutas. Os genótipos araçá-boi apresentaram variabilidade genética de média a alta,obtendo médias das características físicas e físico-químicas superiores às observadas na literatura. Os genótipos G A9, A10 e A6 adotaram frutos com tamanhos maiores e produziram maior número de frutos. Os genótipos A1 obtiveram frutos com maior qualidade organoléptica. Os genótipos A3 produziram frutos com maiores teores de Vitamina C e frutos com maior firmeza. Os genótipos A3, A6, A9 e A10 mostraram-se promissores, com alto potencial agronômico, e puderam ser selecionados para o programa de melhoramento genético da espécie.

Abstract: The objective of this study was to evaluate the genetic diversity between genotypes based on the physical, chemical and physicochemical characteristics of araçá-boi in tropical conditions. The experiment was carried out at the Federal University of Roraima, in the municipality of Boa Vista, Roraima, Brazil. Genotypes were obtained in the F1 generation, through open pollination. Twelve plants were evaluated, with 10 fruits being collected per plant. The physical and physicalchemical characteristics of the fruits were evaluated: fresh mass, length and diameter of the fruits, pulp yield, firmness, mass of the pulp, peel and seeds, number of seeds, soluble solids, tritratable acidity, pH, ratio SS/AT and vitamin C from fruits. The araçá-boi genotypes showed medium to high genetic variability, obtaining averages for the physical and physicalchemical characteristics higher than those observed in the literature. G genotypes A9, A10 and A6 adopted fruits with larger sizes and produced a greater number of fruits genotypes A1 obtained fruits with higher organoleptic quality. Genotypes A3 produced fruits with higher levels of Vitamin C and fruits with greater firmness. Genotypes A3, A6, A9 and A10 were promising with high agronomic potential and could be selected for the genetic improvement program of the species.

Resumo Em América do Sul o camu-camu vêm sendo domesticado, no entanto, para seu cultivo ainda são poucas as informações técnicas para garantir sua adaptabilidade e produtividade em locais com estação seca bem definida. O objetivo neste estudo foi caracterizar a distribuição espacial do sistema radicular e determinar a profundidade efetiva (PE) das raízes em plantas de camu-camu com e sem cobertura vegetal morta (CVM) em condições de terra firme. Num pomar foram escolhidas ao acaso 3 plantas com 3, 5 e 7 anos, cada. Logo foi colocada CVM composta de capim (Trachypogon plumosus) em uma planta de cada idade na projeção da copa. Após 12 meses o volume e PE das raízes nas plantas de 3 anos com CVM foi de 200 mm3 e 0,3 m, e sem CVM foi de 500 mm3 e 0,48 m, respectivamente. Nas plantas com 5 anos foi de 4000 mm3 e 0,43 m com CVM, e sem CVM foi de 6000 mm3 e 0,64 m; e nas plantas com 7 anos o volume e PE das raízes com CVM foram de 12000 mm3 e 0,58 m, e sem CVM de 10000 mm3 e 0,71 m, respectivamente. A profundidade efetiva equivalente ao 80% da concentração das raízes foi menor com o uso de cobertura vegetal morta, o que é muito importante para a cultura do camu-camu, pois permite aplicar uma lâmina de água mais precisa e eficiente por meio da irrigação.

Abstract In South America, o camu-camu has been domesticated, however, for its cultivation there is still little technical information to guarantee its adaptability and productivity in places with a well-defined dry season. The objective of this study was to characterize the spatial distribution of the root system and determine the effective depth (EP) of roots in camu-camu plants with and without mulch (WM) in uplands conditions. In an orchard, 3 plants with 3, 5 and 7 years each were chosen at random. Then mulch composed of grass (Trachypogon plumosus) was placed on a plant of each age in the canopy projection. After 12 months, the volume and EP of the roots in the 3-year-old plants with mulch was 200 mm3 and 0.3 m, and without mulch it was 500 mm3 and 0.48 m, respectively. In 5-year-old plants it was 4000 mm3 and 0.43 m with mulch, and without mulch it was 6000 mm3 and 0.64 m; and in plants with 7 years old, the volume and PE of the roots with mulch were 12000 mm3 and 0.58 m, and without mulch of 10000 mm3 and 0.71 m, respectively. The effective depth equivalent to 80% of the root concentration was lower with the use of dead vegetation cover, which is very important for the camu-camu crop, as it allows the application of a more precise and efficient water layer through irrigation.

Abstract The main limitation of the micropropagation of camu-camu (Myrciaria dubia) is related to in vitro contamination. In order to overcome contamination, the effect of essential oils was studied as an alternative to conventional chemical treatments. This study aimed to analyze the action of essential oils from four condiment and medicinal plants (Oregano, Origanum vulgare L.; Garlic, Allium sativum L.; Citronella, Cymbopogon nardus L.;and Ginger, Zingiber officinale Rosc.) in reducing microbial contamination growth and on the survival rate of explants in the micropropagation of camu-camu. The antimicrobial activity of essential oils was analyzed on the in vitro contamination of tissue culture from camu-camu at concentrations of 0.5, 1, 2, 3 and 4 µL mL-1 in woody plant medium (WPM), emulsified with 1% Polysorbate 80 (Tween 80). The antibacterial activity of essential oils on strains isolated from camu-camu tissue culture was also analyzed using agar diffusion and broth microdilution methods. The use of essential oils allowed a reduction in the rate of in vitro contamination in tissue culture, it being observed that, from the concentration of 2 µL mL-1, there was no manifestation of fungal contaminants, with a significant reduction in the rate of bacterial contamination, with the exception of ginger essential oil that showed significant contamination in all analyzed concentrations. Inversely in relation to the reduction in microbial growth in vitro, there is an increase in explant oxidation as concentrations increase, with citronella and oregano oils showing phytotoxic potential from the lowest concentrations. Garlic essential oil showed better balance, with lower oxidation rates and greater control of microorganisms in tissue culture at concentrations of 0.5 and 1 µL mL-1. Oregano and citronella essential oils showed better antibacterial activity in the agar diffusion test.

Resumo A micropropagação de camu-camu (Myrciaria dúbia) tem como principal limitação a contaminação in vitro. A fim de superar a contaminação, o efeito dos óleosessenciais foi estudado como alternativa aos tratamentos químicos convencionais. Esteestudo teve como objetivo determinar a ação dos óleos essenciais de quatro plantascondimentares e medicinais (Orégano, Origanum vulgareL.; Alho, Allium sativum L.; Citronela,Cymbopogon nardus L.; Gengibre, Zingiber officinale Rosc.) na redução de contaminaçãomicrobiana e sobre a taxa de sobrevivência dos explantes na micropropagação de camu-camu. A atividade antimicrobiana dos óleos essenciais foi analisada sobre a contaminação invitro, na cultura de tecidos de camu-camu, nas concentrações de 0,5, 1, 2, 3 e 4 µL mL-1 em meioWPM, emulsificados com Polysorbate 80 (Tween 80) a 1%. Também foi analisada atividade antibacteriana dos óleos essenciais sobre cepas isoladas da cultura de tecidos de camu-camu, nos métodos de difusão em ágar e microdiluição em caldo. A utilização de óleos essenciais permitiu redução na taxa de contaminação in vitro, na cultura de tecidos,sendo observado que, a partir da concentração de 2 µL mL-1, não houve manifestação de contaminantes fúngicos e redução significativa da taxa de contaminação bacteriana, à exceçãode óleo essencial de gengibre, que apresentou contaminação expressiva em todas as concentrações analisadas. Em ordem inversa à redução no crescimento microbiano in vitro, percebe-se o aumento da oxidação dos explantes à medida que aumentam as concentrações,tendo os óleos de citronela e orégano apresentado potencial fitotóxico desde as maisbaixas concentrações.O óleo essencial de alho apresentou melhor balanceamento, com menor taxa de oxidação e maior controle de microrganismos na cultura de tecidos, nas concentrações de 0,5 e 1 µL mL-1. Os óleos essenciais de orégano e citronela apresentarammelhor atividade antibacteriana no teste de difusão em ágar.

ABSTRACT. The aim of the study was to assess the effect of plant regulators (gibberellic acid and naphthalene acetic acid) and adjuvant LI 700® with and without hand pollination on the fruiting and quality of Annona squamosa L. cultivars. The experiment was conducted in the experimental orchard of the Florida Tropical Research and Education Center (TREC/UF) in Homestead, Florida, USA. The experimental design in random blocks comprised 14 treatments, 10 repetitions and 3 flowers per treatment and per tree for ‘Red’ and ‘Lessard Thai’ cultivars. To assess quality, 9 fruit from each treatment were used, with 3 repetitions and 3 fruit per repetition. High instability was observed in fruit fixation rates between cultivars. The application of growth regulators did not increase fruit fixation in the tested cultivars. The application of naphthalene acetic acid had a deleterious effect on the flowers of the sugar apple cultivars. The most uneven (asymmetrical) fruit was obtained in the treatments with the application of growth regulators. The application of the adjuvant showed toxicity, causing damage to the skin of the fruit. The fruit with the greatest symmetry had the lowest levels of soluble solids and the highest toxicity. The application of growth regulators associated with hand pollination was not efficient, presenting a low percentage of fruit fixation for Annonaceae cultivars. None of the studied treatments produced parthenocarpic fruit (without seeds). The utilization of an adjuvant in the applied concentration caused damage to the fruit peels (darkening) due to toxicity in both cultivars.

RESUMEN El camu-camu (Myrciaria dubia) es una fruta de la región amazónica que ha recibido atención debido a su alto contenido de compuestos antioxidantes, como el ácido ascórbico y los polifenoles. El objetivo del estudio fue seleccionar clones de camu-camu según sus características morfológicas mediante análisis multivariados. Se evaluaron 56 clones de camu-camu distribuidos en tres bloques con dos plantas por parcela experimental. Las variables medidas fueron altura de la planta (H), número de ramas basales (NRB), número de brotes terminales (NBT), diámetro basal del tallo (DT), clorofila a (Chl a) y b (Chl b) y clorofila total (Chl a + b). Los análisis de agrupamiento de componentes principales (PCA) y multivariados se realizaron utilizando la media de enlace y los algoritmos de distancia de Mahalanobis. Después de 24 meses, los resultados mostraron que la característica que menos contribuyó a la selección del clon fue el NRB. La altura de la planta, número de ramas basales (NRB), diámetro basal del tallo (DBT), clorofila a (Chl a) y b (Chl b) y clorofila total (Chl a + b) tuvieron la contribución más positiva hacia la selección inicial de clones de camu-camu a los dos anos de edad. Veintidós clones de camu-camu presentaron la mayor tasa de desarrollo vegetativo o índice de calidad de la vegetación (ICV) en la sabana de transición/área forestal del norte del Amazonas, Brasil, después de dos anos de trasplante.

ABSTRACT Camu-camu (Myrciaria dubia), a fruit from the Amazon region, has received attention due to its high content of antioxidant compounds such as ascorbic acid and polyphenols. This study's objective was to select camu-camu clones according to their morphological characteristic using multivariate analyses. We evaluated 56 camu-camu clones distributed in three blocks with two plants per experimental plot. The variables measured were plant height (H), number of basal branches (NBB), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b). Principal component (PCA) and multivariate clustering analyses were performed using the average linkage mean and Mahalanobis distance algorithms. After 24 months, results showed that the characteristic that least contributed to clone selection was NBB. The plant height (H), number of terminal buds (NTB), basal stem diameter (BSD), chlorophylls a (Chl a) and b (Chl b), and total chlorophyll (Chl a + b) had the most positive contribution towards the initial selection of camu-camu clones at two years of age. The 22 camu-camu clones showed the highest rate of vegetative development or vegetative quality index (VQI) in the transitional savanna/forest area of the northern Amazon, Brazil, after two years of transplanting.

RESUMO Objetivou-se verificar a qualidade fisiológica de sementes de Myrciaria dubia, armazenadas em diferentes ambientes e embalagens durante 300 dias, a partir dos testes de condutividade elétrica, e vigor das plântulas. As sementes foram armazenadas dentro de embalagem de vidro e potes plásticos com água até à superfície do recipiente, no laboratório à temperatura ambiente entre 23 a 25°C e 60-70% UR e em câmara fria à temperatura entre 14-16°C e 50-60% UR. A cada período de armazenamento (0, 30, 60, 120, 180, 240 e 300 dias), foi retirada, de cada recipiente, uma amostra de 110 sementes e submetida às seguintes avaliações: curva de embebição de água, massa seca de sementes, teste de condutividade elétrica, emergência de plantulas e índice de velocidade de emergência. De acordo com os resultados, verificou-se que o armazenamento das sementes de Myrciaria dubia em potes plásticos com água até superfície do recipiente, quer no laboratório e quer na câmara fria, foi indicado para manter a qualidade fisiológica e vigor de plântulas até 300 dias.

ABSTRACT The study aimed to verify the physiological quality of seeds of Myrciaria dubia, stored for 300 days in different conditions and packaging, using tests of electrical conductivity and seedling vigour. The seeds were classified into three weight classes (small, medium and large). Small seeds were considered those with a weight of less than 0.84 g, medium seeds with a weight between 0.86 g and 1.20 g, and large seeds, a weight of greater than 1.22 g. The seeds were stored in glass containers and plastic pots topped up with water, in the laboratory at a room temperature of 23 to 25°C and relative humidity of 60-70%, and in a cold chamber at a temperature of 14-16°C and relative humidity of 50-60%. For each storage period (0, 30, 60, 120, 180, 240 and 300 days), a sample of 110 seeds was used for analyses, including imbibition curve, seed dry weight, electrical conductivity, seedling emergence and emergence speed index. According to the results obtained, the responses of the seeds in both the laboratory and cold-chamber, and stored in plastic pots topped up with water, were indicated for maintaining physiological quality and seedling vigour up to 300 days.

Resumen Debido a la limitada información sobre el cultivo de camote (Ipomoea batatas L.) en áreas silvestres de la sabana, el objetivo de este estudio fue determinar la dosis ideal y el tipo de fertilizante orgánico para el cultivo de camote en suelos de la sabana sin antecedentes de explotación. Se probaron diferentes dosis de fertilizantes en cuatro experimentos: estiércol de ganado (0, 10, 20, 30 y 40 t·ha-1), pollinaza (0, 5, 10, 15 y 20 t·ha-1), compost A (0, 0.75, 1.5, 2.25 y 3.0 t·ha-1) y compost B (0, 0.75, 1.5, 2.25 y 3.0 t·ha-1). El quinto experimento consistió en una prueba de eficiencia de fertilizantes orgánicos utilizando dosis recomendadas para el cultivo de camote, lo cual resultó en seis tratamientos: testigo (sin fertilización orgánica), estiércol de ganado (20 t·ha-1), pollinaza (10 t·ha-1), compost A (1.5 t·ha-1), compost B (1.5 t·ha-1) y compost C (0.375 t·ha-1). En los primeros cuatro experimentos, los productos y dosis recomendadas se definieron en orden de eficiencia de producción: pollinaza (dosis entre 13 y 20 t·ha-1) > estiércol de ganado (dosis entre 30 y 40 t·ha-1) > compost B (dosis entre 0.75 y 2.25 t·ha-1) = compost A (dosis entre 2.25 y 3.00 t·ha-1). Con el quinto experimento se concluyó que: 1) la pollinaza fue el fertilizante inicial más adecuado para el cultivo de camote en suelos de la sabana y 2) el rendimiento del camote estuvo vinculado directamente a la masa de las raíces comerciales, el número de raíces comerciales y la productividad de tallos; las cuales, a su vez, fueron maximizadas al incrementar la materia orgánica y las cantidades de fósforo en el suelo.

Abstract Due to limited information on sweet potato (Ipomoea batatas L.) cultivation in uncultivated savanna areas, the objective of this research was to determine the ideal dose and type of organic fertilizer for sweet potato cultivation in savanna soils with no history of use. In four experiments, the following fertilizer doses were tested: cattle manure (0, 10, 20, 30, and 40 t·ha-1), poultry manure (0, 5, 10, 15, and 20 t·ha-1), compost A (0, 0.75, 1.5, 2.25, and 3.0 t·ha-1), and compost B (0, 0.75, 1.5, 2.25, and 3.0 t·ha-1). The fifth experiment consisted of an organic fertilizer efficiency test using applications already recommended for sweet potato crops, which resulted in six treatments: control (without organic fertilization), cattle manure (20 t·ha-1), poultry manure (10 t·ha-1), compost A (1.5 t·ha-1), compost B (1.5 t·ha-1), and compost C (0.375 t·ha-1). In the first four experiments, the products and their recommended doses were defined in order of production efficiency, as follows: poultry manure (doses between 13 and 20 t·ha-1) > cattle manure (doses between 30 and 40 t·ha-1) > compost B (doses between 0.75 and 2.25 t·ha-1) = compost A (doses between 2.25 and 3.00 t·ha-1). The fifth experiment concluded that: 1) poultry manure was the most suitable starting point for sweet potato cultivation in savanna soils and 2) sweet potato yield was directly linked to the commercial root mass, number of commercial roots, and branch productivity, which, in turn, were maximized by an increase in organic matter and satisfactory amounts of phosphorus in the soil.

ABSTRACT. In vitro culture systems based on liquid culture media are considered to be more effective than semisolid culture medium systems. Liquid culture media systems provide better nutrient availability for plant tissues, easier culture handling, and the potential for scaling up and automation. However, in vitro liquid culture requires more careful handling due to the potential for contamination and the possibility of negative effects, such as hyperhydricity or vitrification, that hinder the growth and development of the plant material. Temporary immersion bioreactors have emerged as a workable alternative for capturing the benefits of liquid media, though semisolid systems are still traditional. Many studies have shown that silicon (Si) is a beneficial plant nutrient. Silicon might have a positive effect in both semisolid and liquid in vitro systems. The objective of this study was to evaluate the effect of silicon on the micropropagation and acclimatization of banana plants cultivated in vitro by comparing liquid temporary immersion bioreactor technology and semisolid traditional culture systems. Different silicon concentrations (0 and 1 mL L-1) and culture systems (liquid temporary immersion bioreactor and semisolid traditional culture) were evaluated over a 36-day period. The growth characteristics plant size, fresh and dry weight, and number and length of leaves and roots were evaluated. After the 36-day in vitro growth period, plants were transferred to a greenhouse for acclimatization and were evaluated after 30 days for the same growth characteristics used in the in vitro studies. The temporary immersion bioreactor system resulted in greater growth of banana plants compared to the traditional semisolid system. Temporary immersion bioreactors also showed a positive interaction with Si and resulted in higher values for all growth characteristics in the acclimatization phase.

ABSTRACT. The present study was carried out to evaluate the antioxidant activity of and the content of bioactive compounds in camu-camu fruits harvested at different maturation stages and stored. The fruits were harvested in the municipality of Cantá, Roraima State, Brazil. The experimental design was completely randomized, with three replications, in a factorial arrangement consisting of three different maturation stages (immature, semi-mature and mature) and eight days of storage (3 x 8). The fruits were analysed every day regarding total vitamin C, carotenoids, anthocyanins, flavonoids, total phenolic compounds, and antioxidant activity (FRAP and DPPH). According to the results obtained, the interaction of maturation stages x eight days of storage had a significant effect according to the F test at 5% probability. The highest antioxidant activity (FRAP) was observed in the fruits harvested in the semi-mature stage, providing a longer shelf life. The carotenoid pigment, flavonoid, anthocyanin, and vitamin C contents were higher in the fruits harvested in the mature stage, and this stage was the most suitable for obtaining these functional biocompounds. Additionally, in mature fruits, the highest mean content of total phenolics and antioxidant activity (DPPH) were observed during storage. It was concluded that the mature stage is the most recommended for the extraction of pigments and antioxidant biocompounds from camu-camu fruits.

Abstract: Caçari is a fruit tree that is native to the Amazon region of Brazil. The fruit is considered to have the highest vitamin C content of any edible fruit (13.757 mg 100 g-1 dry weight). The objective of this study was to evaluate the effects of 2,4-D and 6-BAP alone or in combination on in vitro callus induction and pro-embryogenic mass formation in caçari stem segments in different culture media as a precursor for caçari micropropagation. The experiment consisted of two culture media (MS and WPM) and combinations of four concentrations of 2,4-D (0, 1, 2 and 4 mg L-1) and BAP (0, 0.25, 0.5 and 1 mg L-1). The results showed that the highest percentage of callus formation (99%) was obtained in WPM supplemented with 4 mg L-1, 2,4-D and 1 mg L-1 BAP, and this combination resulted in 93% pro-embryogenic mass formation.

Resumen Myrciaria dubia (Kunth) McVaugh es un árbol frutal nativo de la Amazonía con gran potencial debido a sus propiedades nutracéuticas, por lo que se considera necesario desarrollar tecnologías de adaptación ex situ. El objetivo de este estudio fue estimar la evapotranspiración (ETc) y el coeficiente de cultivo (Kc) de Myrciaria dubia para su domesticación y conservación en suelos de tierra firme. Se trasplantaron, a lisímetros de drenaje, dos plantas de Myrciaria dubia de 2, 4 y 6 años de edad con características morfológicas similares en altura, número de ramas (basales y terminales) y diámetro (de tallo y dosel). Se aplicó, a una planta de cada categoría de edad y en una ocasión, acolchado orgánico compuesto de una hierba nativa (Trachypogon plumosus). Los valores promedio de la ETc de las plantas de 2, 4 y 6 años de edad en presencia y ausencia de acolchado fueron 2 y 2.7 mm·día-1, 3.2 y 3.9 mm·día-1, y 6.1 y 7.2 mm·día-1, respectivamente. Los valores promedio del Kc en las etapas fenológicas EI, EII y EIII, con y sin acolchado, fueron 0.4 y 0.6, 0.6 y 0.8, y 1.1 y 1.3, respectivamente. Los valores de la ETc y el Kc de las plantas de Myrciaria dubia con acolchado orgánico se pueden utilizar en la planificación del riego, la domesticación, la conservación y el uso eficiente de los recursos hídricos en las sabanas tropicales de Roraima, Brasil.

Abstract Myrciaria dubia (Kunth) McVaugh is a fruit tree native to the Amazon with great potential due to its nutraceutical properties; thus, ex situ adaptation technologies should be developed. The objective of this study was to determine the evapotranspiration (ETc) and crop coefficient (Kc) of Myrciaria dubia for domestication and conservation on uplands. Two Myrciaria dubia plants of 2, 4, and 6 years old with similar morphological characteristics of height, number of branches (basal and terminal), and diameter (stem and canopy) were transplanted into drainage lysimeters. Residue of organic mulching composed of a native grass (Trachypogon plumosus) was applied once to one plant of each age category. The mean ETc values for 2-, 4-, and 6-year-old plants in the presence and absence of mulch were 2- and 2.7-mm·day-1, 3.2- and 3.9-mm·day-1, and 6.1- and 7.2-mm·day-1, respectively. The mean Kc values in the EI, EII, and EIII phenological stages with and without mulch were 0.4 and 0.6, 0.6 and 0.8, and 1.1 and 1.3, respectively. The ETc and Kc values for Myrciaria dubia plants with organic mulching can be used in irrigation planning for cultivation, domestication, conservation, and efficient use of water resources in tropical savannas of Roraima, Brazil.

Resumo O objetivo neste trabalho foi determinar aspectos sobre variáveis de crescimento e partição de massa seca das mudas de Khaya senegalensis, bem como a marcha de absorção de nutrientes, em função das épocas e adubação mineral. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 2 x 6. Dois níveis do fator solução nutritiva (sem e com adição) e seis níveis para o fator período (0; 60; 80; 100; 120 e 140 dias). Foram utilizadas 4 repetições, sendo cada uma delas composta de 10 mudas. Para avaliação da qualidade das mudas, consideraram-se os parâmetros morfológicos, relações e índices de qualidade: altura da parte aérea (H; cm); diâmetro do coleto (DC; mm); massa seca da parte aérea (MSPA; g planta-1); massa seca da raiz (MSR; g planta-1); massa seca total (MST = MSPA + MSR; g planta-1); relação massa seca da parte aérea e massa seca da raiz (MSPA/MSR); índice de robustez (IR= H/DC; cm mm-1); e índice de qualidade de Dickson (IQD) e o acúmulo de macronutrientes na parte aérea e sistemaradicular. A adição de solução é recomendada para mudas de Khaya senegalensis a partir da época 100 dias após o transplantio em viveiro de telado na Amazônia setentrional. A manutenção das mudas de Khaya senegalensis com uso de solução nutritiva proporciona as melhores condições para o aproveitamento dos macronutrientes e permite obter mudas aptas para campo em 140 dias após o transplantio em viveiro de telado em Roraima.

Abstract The objective of this work was to determine aspects about growth variables and dry mass partition of Khaya senegalensis seedlings and the nutrient absorption rate, depending on the seasons and mineral fertilization. The experimental design used was completely randomized, in a 2x6 factorial scheme. Two levels of nutrient solution factor (without addition) and six levels of time factor (0; 60; 80; 100; 120 and 140 days). Four replications were used, each one consisting of 10 seedlings. To evaluate the quality of the seedlings, morphological parameters, relationships and quality indexes were considered: Height (H; cm); collar diameter (CD; mm); shoot dry mass (SDM; g plant-1); dry root mass (DRM; g plant-1); total dry mass (TDM = SDW + RDW; g plant-1); shoot dry mass and root dry mass ratio (SDM/DRM); robustness index (RI = H / DC; cm mm -1); the Dickson quality index (DQI) and the accumulation of macronutrients in the shoots and root system. It is recommended to add solution for seedlings of Khaya senegalensis from 100 days after transplanting in the selected nursery in the Amazon. The maintenance of Khaya senegalensis seedlings with the use of the nutrient solution provides the best conditions for the use of macronutrients and obtaining suitable seedlings for the field in 140 days after transplanting in the selected nursery in Roraima.

RESUMO Agonandra brasiliensis é uma árvore de florestas tropicais, com ampla ocorrência na região do Cerrrado brasileiro. Apesar do seu potencial como madeira e para reflorestamento, eficientes protocolos para a produção de mudas ainda estão em falta. Objetivou-se avaliar características morfológicas para a qualidade de mudas de A. brasiliensis, em condições de viveiro, em função do volume do recipiente e dose de fertilizante de liberação controlada. O experimento foi realizado em esquema fatorial 2 x 5, testando-se dois volumes (1,8 L e 2,2 L) de recipiente e cinco doses (0 g L-1, 1 g L-1, 2 g L-1, 4 g L-1 e 8 g L-1) do fertilizante encapsulado Forth Cote® (formulação NPK 15-09-12). As parcelas constituíram-se de cinco mudas homogêneas transplantadas em sacos de polietileno (15 cm x 35 cm) com substrato de areia média lavada. As seguintes características foram mensuradas: comprimento da parte aérea; diâmetro do caule; incrementos em comprimento e diâmetro; matéria seca total; matéria seca da parte aérea e da raiz e a razão entre elas. Também foi determinado o Índice de Qualidade de Dickson. A qualidade das mudas para caracteres morfológicos como comprimento da parte aérea, diâmetro de caule e matéria seca total foi especialmente favorecida por tratamentos que combinaram o fertilizante de liberação controlada em dose aproximada de 5,0 g L-1 e recipiente com volume de 2,2 L.

ABSTRACT Agonandra brasiliensis is a tree from tropical forests, with a wide occurrence in the Brazilian Savannah region. Despite its potential as wood and for reforestarion, efficient protocols for its seedling production are still lacking. This study aimed to assess morphological characteristics for the seedling quality of A. brasiliensis, under nursery conditions, as a function of container volume and controlled-release fertilizer dose. The experiment was carried out in a 2 x 5 factorial scheme, testing two container volumes (1.8 L and 2.2 L) and five doses (0 g L-1, 1 g L-1, 2 g L-1, 4 g L-1 and 8 g L-1) of the encapsulated fertilizer Forth Cote™ (formulation NPK 15-09-12). The plots consisted of five homogeneous seedlings transplanted in polyethylene bags (15 cm x 35 cm) with washed medium sand substrate. The following characteristics were measured: shoot length; stem diameter; increases in length and diameter; total dry matter; shoot and root dry matters and the ratio between them. The Dickson Quality Index was also obtained. The seedling quality for morphological traits, such as shoot length, stem diameter and total dry matter, was especially favoured by treatments combining the controlled-release fertilizer at a dose around 5.0 g L-1 and container volume of 2.2 L.

RESUMO O mogno africano é uma espécie que vêm se destacando na preferência dos empresários como opção no investimento florestal. Porém, estudos e pesquisas sobre a espécie, principalmente no Brasil, são escassos. O objetivo neste trabalho foi estudar a eficiência de absorção, acúmulo, distribuição e uso de nutrientes em Khaya ivorensis e Khaya senegalensis, além de aspectos relacionados as variáveis de crescimento e de partição de matéria seca em função da adubação mineral. Parâmetros morfológicos, fisiológicos e nutricionais foram determinados nas plantas de mogno africano aos 140 dias após o transplantio (DAT). O maior teor de zinco (Zn) foi detectado nas brotações das plantas de Khaya ivorensis e Khaya senegalensis, representando mais de 50% do total acumulado das plantas com adição de solução nutritiva. A manutenção das plantas de Khaya senegalensis e Khaya ivorensis com o uso de solução nutritiva fornece as melhores condições para o uso de nutrientes, e permite que plantas com excelentes características morfológicas e nutricionais estejam prontas para o campo dentro de cinco meses após o transplantio em viveiro sombreado. A absorção, transporte e uso mais eficientes de macro e micronutrientes são encontrados na espécie Khaya senegalensis com a adição de solução nutritiva.

ABSTRACT African mahogany is a species preferred by many entrepreneurs as an investment in the forestry sector. However, there are few studies or research on the species, especially in Brazil. The aim of this work was to study the efficiency of nutrient uptake, accumulation, distribution and use in Khaya ivorensis and Khaya senegalensis, in addition to aspects of growth variables and of dry matter partitioning as a function of mineral fertilisation. Morphological, physiological and nutritional parameters were determined in the African mahogany plants 140 days after transplanting (DAT). The greatest zinc (Zn) content was detected in the shoots of both the Khaya ivorensis and Khaya senegalensis plants, accounting for more than 50% of the accumulated total of the plants with added nutrient solution. Maintaining the plants of Khaya senegalensis and Khaya ivorensis with the use of nutrient solution provides the best conditions for nutrient use, and allows plants with excellent morphological and nutritional characteristics to be ready for the field within five months after transplanting in a shaded nursery. The most efficient uptake, transport and use of macro and micronutrients is found in the species Khaya senegalensis with the addition of nutrient solution.