Daniel Felipe de Oliveira Gentil

Extração, embebição e germinação de sementes de tucumã (Astrocaryum aculeatum)

The aim of this study was to evaluate the influence of the extraction and imbibition period on the germination of tucuma (Astrocaryum aculeatum Meyer, Arecaceae) seeds. After cleaning and drying the pyrenes, the endocarp was broken and removed to liberate the seeds that, before sowing, were soaked in water for 0, 3, 6, 9, 12 and 15 days. The germination was superior to 58%, confirming the possibility of extracting the endocarp without damaging the viability of the seeds. The seeds submitted to nine days of soaking, had a moisture content of 30%, obtained better germination (70%) and index of germination velocity, with mean time of germination of 104 days. The removal of the endocarp and the soaking of seeds accelerated and increased the germination.

Morfologia da plântula em desenvolvimento de Astrocaryum aculeatum Meyer (Arecaceae)

Astrocaryum aculeatum (tucuma) is an Amazonian palm tree, whose fruit pulp is rich in vitamin A and can be consumed fresh or in ice creams, juices, liqueurs and sweets. Its propagation is slow and little knowledge exists about the seed germination and seedling development. This study describes and characterizes the morphological stages of seedling development, during the germination of seeds, pre-treatmented or not with soaking in water. The germination of seeds is of the adjacent ligular, cryptocotylar and hypogeal type. The time to each stage was shorter for the soaked seeds, indicating a beneficial effect on the speed of the germination process, with mean time of emergence of the cotyledonal petiole being 99 days and complete expansion of the first leaf bifid by 253 days.

Storage of camu-camu (Myrciaria dubia) seeds with different moisture contents and temperatures

O objetivo do presente trabalho foi avaliar a qualidade fisiologica das sementes de camu-camu (Myrciaria dubia (H.B.K.) McVaugh), com diferentes graus de umidade (46 e 40%), submetidas a diferentes condicoes (temperatura ambiente - media de 26,5°C, câmara a 20°C e câmara a 10°C) e periodos de armazenamento (30, 60, 90, 120 e 150 dias). Apos cada periodo, foram retiradas amostras dos tratamentos para as avaliacoes do grau de umidade e da qualidade fisiologica das sementes. A reducao do grau de umidade afetou negativamente a viabilidade e o vigor das sementes, e a temperatura de 10°C nao foi favoravel ao armazenamento das sementes. Assim, as sementes de camu-camu devem ser armazenadas com grau de umidade elevado (proximo a 46%) e, preferencialmente, sob temperatura de 20°C, para manter a viabilidade e o vigor por maior periodo de tempo.

Viabilidade e superação da dormência em sementes de Araçá-boi (Eugenia stipitata ssp. sororia)

Eugenia stipitata ssp. sororia McVaugh - Myrtaceae is a small Amazonian fruit tree with considerable economic potential. The present work investigated the effects of dehydration on seed viability and evaluated methods of overcoming seed dormancy by mechanical scarification (by peeling and sanding). The physiological quality of seeds is affected by reduction in moisture content. Seeds show recalcitrant behaviour with a critical moisture content between 58,8 and 47,1 %. No seeds survived dehydration to moisture contents of less than or equal to 25,76%. In view of the detrimental effects of drying, seeds should preferably be sown immediately after being extracted and cleaned. The seed integument offers mechanical resistance to expansion of the embryo. Total removal of the integument proved to be the most efficient method of overcoming dormancy since it eliminates resistance in the region where the embryo normally breaks through. The average time for emergence was 66 days and the final percentage emergence was 96%. Simple abrasion of the integument caused mechanical injury to the seeds with adverse consequences on emergence and vigour.

QUALIDADE FISIOLÓGICA E TAMANHO DE SEMENTES DE CENOURA

Maturation of carrot seeds occurs in a sequence based on the different orders of the umbel. Since harvest is carried out only at one stage, nonuniform seed sizes within the same seed lot may occur. The effect of seed size on physiological quality was determined. Four lots of commercial carrot seeds (cv. Brasilia) were separated in three fractions: large (retention at 2 mm diameter); medium (retention at 1.5 mm diameter) and a mixture of large and medium seeds (1:1 proportion). These fractions were tested for germination, tetrazolium reduction, electrical conductivity, accelerated aging and seedling emergence. Only seedling emergence, evaluated after 14 days, showed statistical difference. However this test did, not show consistency for the separation of the fractions into different quality levels, for different lots.

Conservação de sementes de Myrciaria dubia (H.B.K.) McVaugh

Myrciaria dubia seeds have a short life span and few informations are available about the factors that determine their storability. The main aim of this research work was to check the effects of three temperatures (10 oC, 20 oC and 30 oC) and eight seed moisture contents (48%, 43%, 40%, 34%, 30%, 24%, 18% and 14%) on seed storability, during a time period of 280 days. Periodic evaluations of seed moisture content, germination, vigor and healthness were carried out throughout the experimental time. The best seed storability conditions were observed at 10 °C and 43% of seed moisture content.

PROPAGAÇÃO ASSEXUADA DO CAMU-CAMU (Myrciaria dúbia) ATRAVÉS DE ENXERTIAS DO TIPO GARFAGEM

The camu-camu tree (Myrciaria dubia (H.B.K.) McVaugh), an Amazonian native species whose fruits possess very high vitamin C content, is normally propagated by seeds that do not guarantee the reproduction of good characteristics. The objective of the present study was to evaluate the asexual propagation of camu-camu through different grafting methods for multiplication of the selected plants in Manaus, Amazonas, Brazil. The grafting was carried out with 1 year-old root-stocks grown under 50 % shade, with an average stem diameter of 6 mm and height of 80 cm. The side cleft graft (65 % take) and simple side graft (52 %) were the methods that gave best results. The top cleft graft (34 %) and saddle graft (9 %) were not satisfactory, although the first had not differ significantly from methods that showed best results.

Caracterização física de frutos e sementes de goiaba-da-costa-rica, produzidos em Manaus, Amazonas

The Costa Rican guava (Psidium friedrichsthalianum) is a native fruit tree species of Central America cultivated in home gardens. The physical characterization of fruits and seeds of this species was done with the aim of contributing for the establishment of the implementation of techniques and commercial crops management. In this way, it was verified that the average fruit fresh weight was 42.19g, and pulp fresh weight was 39.72g, and seed fresh weight was 2.47g, with 72.8 seeds per fruit. The seeds are irregularly shaped, with average length, width and thickness of 4.29mm, 4.11mm and 2.68mm, respectively. The fruit presents favorable attributes for industrial exploitation, with high pulp yield (94%) and a round shape, somewhat flattened on the apex and base (longitudinal diameter/transversal diameter ratio = 0.83). The high seed number per fruit represents a characteristic that facilitates the propagation and seedling production of the species.

Métodos de extração e limpeza de sementes de araçá-boi (Eugenia stipitata)

The araca-boi (Eugenia stipitata McVaugh, Myrtaceae) an Amazonian species, has fruits with agreeable aroma and flavour, and high pulp yield. This study evaluated physical and physiological seed qualities after hand and mechanical extraction, cleaning by friction with different materials (sand, sawdust, sand+sawdust, hydrated lime, on a sieve, and without friction) and cleaning by natural fermentation (with and without change of water every 0, 1, 2, 3, 4 c 7 days). The mechanical method allowed extraction of the largest quantity of pulp (78% of weight and 81% of fruit volume). Friction with hydrated lime gave the highest percentage (98 %) and germination speed (0,989). Under natural fermentation, keeping the same water for more than one day negatively affected the physiological quality of the seeds.

Preparação das subamostras, temperatura e período de secagem na determinação do grau de umidade de sementes de camu-camu (Myrciaria dubia (H.B.K.) McVaugh)

Wheat and soybean seed sector is one important branche of Rio Grande do Sul State agribusiness, Brazil. However, there are few studies towards market analysis and, when present, they don,t consider the seed company peculiarities. To fullfill this lacune, one study was accomplished with the objective of elaborate a diagnostic of the seed sector, centering the analysis on how seed companies act. This study used secondary data, in wich inputs and outputs of the seeds companies were analyzed. The institutional relationship of these companies and genetic breeding programs was treated as inputs. Their performance in scale, management, new varieties and destiny of their sales, among other, were considered outputs. Multivariate techniques of analysis were used. To identify groups by performance on the outputs, clusters analysis was accomplished for correspondence analysis with the inputs. The study showed that seed companies with small and very small production scale, up to 460 and 955 tons for wheat and soybean, respectively, are majority in the Rio Grande do Sul State. Those companies without institutional relationship and genetic breeding programs, presented also the worst performance in scale, innovation and segmentation.The objective of the present study was the appraisal of the preparation of samples (whole and cut seeds), temperatures (80 and 105oC) and drying periods (12, 24, 36, 48, 60, 72 and 96 hours) in the determination of the moisture content of camu-camu seeds. The number of seeds was evaluated by kilogram, using a table of maximum tolerances allowed for differences between two samples, and the variation in the results of moisture content among samples of seed lots was analyzed. Thus, it was verified that the number of seeds per kilogram was inferior to 5000 units and that 33% of the lots exceeded the tolerances of moisture content allowed by the Brazilian Rules for Testing Seeds. On the other hand, it was not possible to establish the most appropriate method to determine the moisture content of the seeds of this species, but the combination cut seeds/temperature 105oC, in any exposition period, and the combinations of whole seeds and cut seeds in the temperature of 80oC/12 hours of exposition were considered inadequate.