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We evaluated farmers’ rationales to understand their decision making in relation to the use of fertile anthropogenic soils, i.e., Amazonian dark earths (ADE), and for dealing with changes in shifting cultivation in Central Amazonia. We analyzed qualitative information from 196 interviews with farmers in 21 riverine villages along the Madeira River. In order to decide about crop management options to attain their livelihood objectives, farmers rely on an integrated and dynamic understanding of their biophysical and social environment. Farmers associate fallow development with higher crop yields and lower weed pressure, but ADE is always associated with high yields and high weeding requirements. Amazonian dark earths are also seen as an opportunity to grow different crops and/or grow crops in more intensified management systems. However, farmers often maintain simultaneously intensive swiddens on ADE and extensive swiddens on nonanthropogenic soils. Farmers acknowledge numerous changes in their socioeconomic environment that affect their shifting cultivation systems, particularly their growing interaction with market economies and the incorporation of modern agricultural practices. Farmers considered that shifting cultivation systems on ADE tend to be more prone to changes leading to intensification, and we identified cases, e.g., swiddens used for watermelon cultivation, in which market demand led to overintensification and resulted in ADE degradation. This shows that increasing intensification can be a potential threat to ADE and can undermine the importance of these soils for agricultural production, for the conservation of agrobiodiversity, and for local livelihoods. Given that farmers have an integrated knowledge of their context and respond to socioeconomic and agro-ecological changes in their environment, we argue that understanding farmers’ knowledge and rationales is crucial to identify sustainable pathways for the future of ADE and of smallholder agriculture in Amazonia. © 2016 by the author(s).

The study aimed to estimate parameters and breeding values for the traits number of bunches (NC), average weight of bunch (PMC) and total weight of the bunch (PTC) in palm-trees on six years, by the method of mixed models (REML/BLUP). The progeny test was established under a randomized block design with 50 treatments (progeny), 10 blocks and one plant per plot, spaced 5 × 5 m, and an outer boundary to the experiment. Magnitudes of heritability estimates at the individual level and averages in the narrow sense for PTC (0.21 and 0.36) and NC (0.286 and 0.435) were good. The coefficient of genetic variation at the level of individual exhibited moderate values for PTC (19.86) and NC (17.59). The square root of heritability for the average of the progeny results in selective accuracy in the order of 0.60 to 0.66 for PTC and NC, confirming good accuracy and confidence in genetic parameters estimated by promoting security in the selection. The potential fo the population for improvement can be observed by means of genetic gains for PTC that ranged from 8.3 to 19.9 kg, increasing the mean of the new population for the character, after one cycle of selection to 40.4 kg, equivalent to 25.8%.

The objective of this work was to characterize the oleoresin of copaiba (Copaifera reticulata) and to estimate genetic variability of the species in the Tapajós National Forest, PA, Brazil, using microsatellite markers. Sampling was performed in two areas, 5 km apart, in 136 trees. Genetic diversity was evaluated with six microsatellite markers derived from C. langsdorffii, and the oleoresin obtained from 30 trees (15 from each area) was physically and chemically characterized. Oleoresin from C. reticulate has a liquid, thin aspect, with a weak odor and yellowish-gilded color (73.3% of the plants), highly variable viscosity (18 to 187 Pa-s), and mean density of 0,975±0,049 g cm-3. Its acidity index varied from 9.62 to 10.17 mg g-1 of KOH and the saponification index from 100.63 to 109.84 mg g-1. The molecular analysis identified 78 alleles, with an average of 13 per locus. The expected heterozygosity varied from 0.59 to 0.85 (mean of 0.75) and the inbreeding level, from 0.375 to 0.419. The genetic differentiation between populations in the different sampling areas was low (FST = 0.030), but the variability was higher between the genetic groups detected by Structure software (FST = 0.070). This higher variability indicates that the genetic diversity of copaiba is not threatened in the mid-term.

This study aimed to predict breeding values and estimation of variance components for growth traits, disease incidence and timing of the production of half-sib progenies of guarana in an experiment conducted in Maués, Amazonas. Thirty-six families were evaluated in an experimental design of randomized blocks with two replications and six plants per plot for the characters plant height and stem diameter (cm), anthracnose resistance and witches (scale 0-4) and fruit production (g / plant). The variance components and genetic parameters were estimated by the procedure REML / BLUP. All characteristics are greatly influenced by the environment. The greatest genetic gain for early production are obtained with the selection of subjects using both the variation between and within the progeny combined through BLUP. The average of the first production of the best individual was 7720 g / plant, which is five times higher than the state average productivity. The largest genetic gains are the characteristics plant height, stem diameter, and early production. Selection for resistance to anthracnose and witches will be more efficient if performed at the level of progeny and not between individuals within progenies. Este trabalho teve como objetivo predizer valores genéticos e estimar componentes de variância para caracteres de crescimento, incidência de doenças e precocidade da produção de progênies de meios irmãos de guaranazeiro, num experimento conduzido em Maués, Amazonas. Trinta e seis progênies foram avaliadas num delineamento experimental de blocos ao acaso, com duas repetições e seis plantas por parcela para os caracteres altura de planta e diâmetro do caule (cm), resistência à antracnose e ao superbrotamento (escala de 0 a 4), e produção de frutos (g/planta). Os componentes de variância, parâmetros e valores genéticos foram estimados pelo procedimento REML/BLUP. Todas as características avaliadas são muito influenciadas pelo ambiente. Os maiores ganhos genéticos para produção precoce são obtidos com a seleção de indivíduos, usando tanto a variação entre quanto dentro das progênies, combinadas por meio do BLUP. A média da primeira produção do melhor indivíduo foi de 7720 g/planta, que é cinco vezes maior do que a produtividade média estadual. Os maiores ganhos genéticos são das características altura de plantas, diâmetro do caule e produção precoce. A seleção para resistência à antracnose e ao superbrotamento será mais eficiente se realizada em nível de progênies e não entre os indivíduos dentro das progênies.

This work aimed to study the genetic variability, to estimate genetic and phenotypic parameters predict genetic values, establishing genetic correlations between characters and construirum selection index of individuals of guarana (Paullinia cupanavar. Sorbilis) in an experiment conducted in Maués, Amazonas. Thirty eseis progenies were evaluated for 10 morphological characteristics, including resistance to anthracnose disease and witches and fruit production in three consecutive years in experimental design of randomized blocks with two replications and six plants per plot. The variance components, and genetic and phenotypic parameters were estimated by the procedure REML / BLUP. There phenotypic and genetic variability among progenies for fruit production, which can be exploited in the breeding program. The genetic gains obtained in this study indicate a larger gain than the clonal selection. The selection of individuals for seed production and composition of the population of improvement should be evaluated for four more years. This work aimed to study the genetic variability, to estimate genetic and phenotypic parameters and predicting breeding values of individuals of guarana (Paullinia cupana var. Sorbilis) in an experiment conducted in Maués, Amazonas. Thirty-six families were evaluated for 10 morpho-agronomic characters, including resistance to anthracnose disease and witches and fruit production in three consecutive seasons, an experimental design of randomized blocks with two replications and six plants per plot. The variance components, and genetic and phenotypic parameters were estimated by the procedure REML / BLUP. The strategy of selecting progenies involving all morpho-agronomic traits proved to be more efficient in regard to genetic gains of 100% and should be adopted in the breeding program of guarana. Moreover, the selection of individuals to seed production and breeding population composition must be further evaluated for over four years since the present genetic gain, ranging from 1.38% to 2.58% did not allow taking a safe decision. Este trabalho teve como objetivos estudar a variabilidade genética,estimar parâmetros genéticos e fenotípicos, predizer valores genéticos,estabelecer correlações genéticas entre os caracteres e construirum índice de seleção dos indivíduos de guaranazeiro (Paullinia cupanavar. sorbilis) num experimento conduzido em Maués, Amazonas. Trinta eseis progênies foram avaliadas para 10 caracteres morfoagronômicos, incluindo resistência às doenças antracnose e superbrotamento e produção de frutos, em três safras consecutivas, num delineamento experimental de blocos ao acaso, com duas repetições e seis plantas por parcela. Os componentes de variância, parâmetros e valores genéticos e fenotípicos foram estimados pelo procedimento REML/BLUP. Existe variabilidade fenotípica e genética entre as progênies para a produção de frutos, que pode ser explorada no programa de melhoramento. Os ganhos genéticos obtidos neste trabalho apontam para um ganho maior do que o da seleção clonal. A seleção de indivíduos para produção de sementes e composição da população de melhoramento deve ser avaliada por mais quatro anos. Este trabalho teve como objetivo estudar a variabilidade genética, estimar parâmetros genéticos e fenotípicos, e predizer valores genéticos dos indivíduos de guaranazeiro (Paullinia cupana var. sorbilis) num experimento conduzido em Maués, Amazonas. Trinta e seis progênies foram avaliadas para 10 caracteres morfo-agronômicos, incluindo resistência às doenças antracnose e superbrotamento e produção de frutos, em três safras consecutivas, num delineamento experimental de blocos ao acaso com duas repetições e seis plantas por parcela. Os componentes de variância, parâmetros e valores genéticos e fenotípicos foram estimados pelo procedimento REML/BLUP. A estratégia de seleção de progênies envolvendo todos os caracteres morfo-agronômicos mostrou-se ser a mais eficiente no que concerne aos ganhos genéticos da ordem de 100%, devendo ser adotada no programa de melhoramento genético do guaranazeiro. Por outro lado, a seleção de indivíduos para produção de sementes e para composição de população de melhoramento deve ser mais bem avaliada, por mais quatro anos, pois os ganhos genéticos atuais, variando de 1,38% a 2,58%, não permitem uma tomada de decisão segura.

The hybrid populations of peach palm (Bactris gasipaes Kunth) have accumulated genetic variability from adjacent landraces, which is expected to increase their variability. To test this hypothesis, 176 plants maintained in the peach palm Germplasm Bank at INPA, including four hybrid populations [Belém (n=26); Manaus (n=38); Iquitos, Peru (n=41); Yurimáguas, Peru (n=41)], two wild populations (B. gasipaes variety chichagui) types 1 (n=21) and 3 (n=7), and two samples of a related species, B. riparia, were genotyped with RAPD markers and compared to adjacent landraces reported in other studies. Eight RAPD primers generated 88 polymorphic and 11 monomorphic markers. The replicability test presented a Dice similarity of 0.67, considered acceptable. The average heterozygosity of the hybrid populations was 0.34 and the polymorphism was 87.9%, greater than in the wild populations (0.31; 74.7%). The dendrogram of Dice similarities did not present groups that clearly correspond to the hybrid populations. The gene flow between Iquitos and Yurimáguas (Nm=12.75), and between Iquitos and Manaus (Nm=9.47) was high, while between Belém and Manaus it was lower than expected (Nm=7.72), probably due to the influence of the Solimões landrace near Manaus. The high value of heterozygosity in Manaus seems to be the result of the union of two dispersals after domestication: the western Amazonian dispersal, with Iquitos and Yurimáguas, and the eastern Amazonian, with Belém, joining in Manaus. However, these hybrid populations did not present an accumulation of genetic variability expressive enough to differentiate them from the landraces.

Peach palm is a native Amazonian fruit species with broad genetic diversity in its wild and domesticated populations. This study completed the molecular characterization and genetic analysis of the accessions in the Peach Palm genebank, Brazil, using RAPD markers. Eight primers generated 132 markers, of which 128 were polymorphic. Average heterozigosity was 0.35, with 95.5% polymorphism. The genetic variability within the landraces (H S) was 0.32, while genetic divergence (G ST) was 0.09 among the four well-represented landraces. The average gene flow was 5.0, with high gene flow between the Solimões and Pampa Hermosa (Nm=10.07), and between the Putumayo and Solimões (Nm=10.73) landraces, all western landraces. The dendrograms of the Nei's and Rogers' genetic distances of the well-represented landraces presented similar groupings to previous analyses, with the Solimões, Putumayo and Pampa Hermosa landraces grouped together in western Amazonia, and distant from the Pará landrace in central and eastern Amazonia. A pupunheira é uma fruteira nativa da Amazônia com ampla diversidade genética em suas populações silvestres e domesticadas. Este estudo finalizou a caracterização e análise genética dos acessos do germoplasma, usando marcadores moleculares RAPDs. Oito iniciadores geraram 132 marcadores, com 128 polimórficos. A heterozigosidade média foi 0.35 com 95.5% de polimorfismo, similares a outros estudos. A variabilidade dentro (Hs) das raças bem representadas foi 0,32, enquanto a divergência genética (G ST) foi 0,09 entre as quatro raças bem representadas. O fluxo gênico médio foi 5,0, com alto fluxo gênico entre as raças Solimões e Pampa Hermosa (Nm=10,07), e as raças Putumayo e Solimões (Nm=10,73), sendo todas ocidentais. Os dendrogramas das distâncias de Nei e Rogers mostraram que raças bem representadas apresentaram grupos similares às análises anteriores, com as raças Solimões, Putumayo e Pampa Hermosa agrupadas no oeste da Amazônia, e distantes da raça Pará no centro e leste da Amazônia.

Peach palm is a native Amazonian fruit species with broad genetic diversity in its wild and domesticated populations. This study completed the molecular characterization and genetic analysis of the accessions in the Peach Palm genebank, Brazil, using RAPD markers. Eight primers generated 132 markers, of which 128 were polymorphic. Average heterozigosity was 0.35, with 95.5% polymorphism. The genetic variability within the landraces (H S) was 0.32, while genetic divergence (G ST) was 0.09 among the four well-represented landraces. The average gene flow was 5.0, with high gene flow between the Solimões and Pampa Hermosa (Nm=10.07), and between the Putumayo and Solimões (Nm=10.73) landraces, all western landraces. The dendrograms of the Nei's and Rogers' genetic distances of the well-represented landraces presented similar groupings to previous analyses, with the Solimões, Putumayo and Pampa Hermosa landraces grouped together in western Amazonia, and distant from the Pará landrace in central and eastern Amazonia.