Açaí (Euterpe oleracea Mart.) - a common tropical palm has high social, economic, and environmental importance in the Amazon region. In the light of increasing exploration to obtain the fruit and heart of this palms, comprehensive studies are warranted for conservation and genetic improvement. Here, we characterized açaí accessions using phenological, morphological, and agronomic descriptors and random amplified polymorphic DNA (RAPD) molecular markers for joint selection of accessions with greater productivity. Hundred accessions were analyzed using 18 morphoagronomic descriptors and 13 RAPD markers. The spathe and inflorescence emission phases during flowering and fruiting showed seasonality. Based on the coefficient of variation and mean squared error, the accessions exhibited high variability in the tested morphoagronomic descriptors and were distributed into seven groups. Fruit, seed, and pulp weights were important descriptors for the distinction of accessions and identification of those with greater productivity. The accessions presented >85% similarity, and 85 accessions, distributed in nine subgroups, could not be differentiated using RAPD markers. There was no correlation between grouping based on morphometric descriptors and RAPD markers. Panicle weight was 3.9-9.0 kg in 15 accessions and 100-fruit pulp weight was 35-50 g in six accessions. Therefore, accessions with high productivity could be selected.

The objective of this work was to evaluate the response of the BRS Tumucumaque cowpea (Vigna unguiculata) cultivar to liming and to phosphorus and potassium fertilization in the absence of inoculation or nitrogen fertilization, as well as to inoculation with selected Bradyrhizobium strains, in an upland forest area in the state of Amapá, eastern Amazon, Brazil. Seven experiments were conducted in field conditions, in order to evaluate six limestone, four phosphorus, and four potassium rates, besides the inoculation with four Bradyrhizobium strains. Leaf nitrogen concentrations, pod and grain dry mass per plant, grain yield, and soil pH, Al+3, and Ca+2 + Mg+2 were evaluated. The obtained data were subjected to the analysis of variance, to the regression analysis, or to test to compare means. The soil presented a high buffer power, but liming reduced its chemical limitations. Leaf nitrogen concentrations were correlated to cowpea grain yield. However, there is no effect of the interaction between potassium and phosphorus rates on grain yield. In addition, grain yield is not influenced by liming and potassium fertilization, but is increased by phosphorus fertilization. Inoculation with the UFLA 3-84 and INPA 03-11B strains promotes a greater grain yield than that with BR 3262 and BR 3267, as well as a similar grain yield to that of the control without inoculation.

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RESUMOA modelagem de distribuição em classes diamétricas é um dos meios de indicar o potencial uso de uma comunidade florestal. Nesse sentido, objetivou-se avaliar a estrutura diamétrica de espécies lenhosas da Amazônia por meio das Funções de Densidades Probabilísticas (FDP's). O estudo foi desenvolvido no município de Porto Grande, Amapá. Foi instalada uma parcela permanente de 100 m x 100 m, e feitas mensurações em todos os indivíduos que apresentaram diâmetro à altura do peito (DAP) igual ou superior a 10,0 cm. Para as análises de representatividade para os ajustes das funções foi utilizado o programa "R development core team". O critério de informação de Akaike -AIC foi empregado como critério de seleção. Os resultados encontrados indicaram que a função Gamma foi a que melhor descreveu a distribuição diamétrica para Manilkara huberi e Pseudoxandra cuspidata. Já as espécies Protium decandrum e Virola venosa a função Log-Normal foram as que apresentaram melhores aderências. De modo geral, a função normal não apresentou uma aderência satisfatória para todas as espécies. Conclui-se que, a função Gamma proporcionou o melhor ajuste para as espécies e a distribuição diamétrica pode ser utilizada como mecanismo para exploração volumétrica de madeira e projeção da produção futura. PALAVRAS-CHAVE: distribuição probabilística; funções de densidades; manejo florestal.