Genetic similarity of natural populations of pimenta-demacaco (Piper aduncum L.) obtained throug RAPD analysisThe species known as pimenta-de-macaco (Piper aduncum L.) has great economic explotation potential based on the proved usefulness of the essential oil in agriculture and human health. The genetic diversity of their natural populations was characterized. A total of eighteen accessions of the plant, obtained from four different origins in the Brazilian Amazon, was examined by means of DNA loci, generated by RAPD analysis. Real genetic diversity was observed between the analyzed populations and it appear that the patterns of the genetic diversity follow the patterns of the geographical distribution.

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Spiked pepper presents a high yield of essential oil with useful biological properties for human health and agriculture. In order to evaluate the morphoagronomic variability and, afterwards, to select genotypes for plant breeding and cultivation, thirteen clones were propagated. Thus, spiked pepper cuttings were rooted under greenhouse, transferred to a nursery and, afterwards, planted at the experimental area. The evaluations were carried out in two harvest seasons. The evaluated morphoagronomic traits were number of leaves per branch, leaf length, leaf width, diameter of the oldest branch, plant height, number of orthotropic branches, number of plagiotropic branches, internode length, fresh and dry matter, yield of essential oil and dillapiole content. The analysis of variance and the Scott-Knott test were utilized for data analysis and comparisons among clones and parentals were carried out through genetic and experimental variation coefficients. Fresh matter (first season), number of orthotropic branches and diameter of the the oldest branch (second season) presented variability. The Scott-Knott test detected variability for fresh matter, dillapiole content (first season), diameter of the oldest branch and number of orthotropic branches (second season). The yield of essential oil and the dillapiole content were higher for the clones than for the parentals. In conclusion, the clones showed adaptability to the soil and climate conditions of Belém, Pará State, Brazil; the harvest time influenced the oil yield and the dillapiole content; the variance analysis evidenced uniformity and productivity for the evaluated clones, suggesting they can be recommended for cultivation on small-scale production systems in this location.

Spiked pepper (Piper aduncum L.) is an aromatic plant species with high essential oil production. It is a species that occurs abundantly in the Brazilian Amazon. Its essential oil has exploitable biological properties in the human health and agriculture. Aiming to study its germplasm toward future use in genetic breeding programs, collecting was carried out (inflorescences, cuttings, leaves and thin branches) in ten provenances from the Brazilian Amazon. Twelve morphoagronomic traits were determined to take the data: number of leaves by branch, length of leaf, width of the leaf, circumference of the older branch, height of the plant, number of orthotropic branches, number of plageotropic branches, length of the internodes, number of spikes per branches, yielding of oil, content and production of dillapiole, as well as data on the environment and populations of spiked pepper. The inflorescences and cuttings were encoded and sent for the Federal Rural University from Pará State (UFRA), Brazil, for propagation. The leaves and thin branches were sent for the Emílio Goeldi Museum, from Pará State (MPEG) for extraction of essential oil (hydrodistillation). Estimators of amplitude of variation, mean, standard deviation and coefficient of variation were utilized to study the phenotypical variability. The morphoagronomic traits of largest variability were number of orthotropic branches, number of spikes per branch, circumference of the older branch and the content and production of dillapiole. This species has adapted to many different environments of vegetation, soil, climate, relief and drainage becomming easy the domestication and cropping. There is morphoagronomic variability pleasing the selection and genetic breeding.

Spiked pepper is a plant species with properties that allow the development of natural agrochemicals and medicines, showing large potential of use by humanity. With aim to ascertain the phenotypical variability, 41 parentals were analyzed, sampled in the States of Pará and Amazonas. Principal Component analysis and Jolliffe's criterion were utilized for discarding of variables, subsidized by the Pearson's Correlation. It took seven components to explain 80% of the variation. The essential oil yield and number of leaves per branch were suggested to be discarded because they are the characteristics that have contributed least to the total variance. The 3D scatter diagram constituted a relatively homogeneous and continuous clustering, identifing a divergent pair: PA-020 (Marabá-PA) and PA-035 (Santa Isabel-PA). The analyzed traits have variability potentially able to discriminate the parentals, whereas 83.3% of such traits can be used for this purpose. The divergent genotypes identified on 3D scatter diagram analysis can be used in breeding programs for the development of superior genotypes. A comparison with preexisting molecular data of some genotypes permited to conclude that there was one certain agreement degree between morphological and molecular characterizations and that molecular characterization presented higher discriminatory power, using a smaller number of genotypes, identifying dissimilar genotypes and clusters, although analyzed by different multivariate statistic methods.