Camu-camu is an native species in domestication processes. Therefore, studies related to the root system are necessary to evaluate the best cultivation practices for an orchard. Two trials were conducted, one with nitrogen (N) and the other with potassium (K), at doses of 0, 40, 80, 160, and 320 kg·ha–1. Root distribution was determined using nondestructive analyses in which two-dimensional (2D) root images were obtained from trenches under the plants’ canopy. Variables included width (measured in cubic millimeters), area (measured in square millimeters), and length (measured in millimeters, and were analyzed using Safira software (version 2010, Embrapa, Brazil). To have better spatial visualization of variable distribution in the soil profile, data were analyzed using the ordinary kriging technique with the geoR software package and R software (version 2016). Both N and K doses inf...

Changes in soil attributes following changes in management strategies in rice cultivation can alter soil quality, either positively or negatively. The aim of this study was to evaluate soil quality indicators, based on physical, chemical and microbiological soil attributes in Amazonian savanna under rice cultivation with different ages. The research was conducted in five areas under continuous rice cultivation during 1, 3, 8, 13, and 25 years, compared with local reference native vegetation. Soil samples were collected at 0-10 cm depth and evaluated for physical attributes such as texture and bulk density, chemical properties such as soil organic carbon, total nitrogen, exchangeable cations, available P, pH, CEC and C/N ratio; and microbiological attributes like microbial biomass carbon, soil microbial respiration, metabolic ratio and microbial coefficient. Acid phosphatase and urease ac...

In order to select camu-camu superior genotypes, a comparative of clones from natural populations, farmer plantations and an experimental field of the National Institute of Agrarian Innovation (INIA), was established in 2004 in varzea, at the Peruvian Amazon Research Institute (IIAP). Nine harvests between 2006 and 2016 have been evaluated, including variables in vegetative and reproductive development states. Statistical analysis was performed using the SPSS program for analysis of variance and SELEGEN REML/BLUP for repetitivity analysis of “fruit yield” (FY) and “fruit weight” (FW) with 5 and 4 measurements (years) respectively. For FY, a repetitivity index r = 0.117±0.07 was obtained with a selective precision of 0.63 and efficiency of 1.84 where clones 69, 48, 58, 50, 61, 13, 18, 29, 49 and 32, were selected in descending order of merit. For FW, r = 0.690±0.294 was obtained...

The research summarized and validated the individual selection of camu-camu (Myrciaria dubia (Kunth) McVaugh) plants. 43 progenies, previously selected in genetic tests and fields of producers of flood areas, were evaluated. Each progeny was installed in a row of 10 half-sister plants, with a space of 3x2 m. Using the SELEGEN (Reml / Blup) Model 63 program, four crops were analyzed, and individuals were selected for each of the 16 descriptors evaluated. For fruit yield, the Tipishca-Río Tigre population stood out, occupying 5 of the first 10 places. The individuals TT0725-4 (Tigre-Tipishca) turned out to be a natural recombinant for fruit yield / weight. And individual 64-8 turned out to be triple recombinant (yield / fruit weight / ascorbic acid). The descriptors with the highest genetic control with r ≥ 0.30 were: average fruit weight, brix degrees, plant height, number of basal bra...

The research summarized and validated the individual selection of camu-camu (Myrciaria dubia (Kunth) McVaugh) plants. 43 progenies, previously selected in genetic tests and fields of producers of flood areas, were evaluated. Each progeny was installed in a row of 10 half-sister plants, with a space of 3x2 m. Using the SELEGEN (Reml / Blup) Model 63 program, four crops were analyzed, and individuals were selected for each of the 16 descriptors evaluated. For fruit yield, the Tipishca-Río Tigre population stood out, occupying 5 of the first 10 places. The individuals TT0725-4 (Tigre-Tipishca) turned out to be a natural recombinant for fruit yield / weight. And individual 64-8 turned out to be triple recombinant (yield / fruit weight / ascorbic acid). The descriptors with the highest genetic control with r ≥ 0.30 were: average fruit weight, brix degrees, plant height, number of basal bra...

The structure of tree communities in tropical forests depends on environmental filters and biotic interactions such as competition and facilitation. Many ecotone forests in Northern Amazonia are intriguingly populated by tree assemblages characterized by distinct abundances of a single species, Peltogyne gracilipes (Leguminosae). It is unclear whether this pattern solely reflects environmental filters or also antagonistic interactions among species with similar habitat requirements. The aim of this study was to determine the response of species richness and composition to environmental filters, and analyze the role of P. gracilipes in structuring tree communities in ecotone forest areas of the Northern Brazilian Amazonia. We sampled 129 permanent plots along a hydro-edaphi gradient. All arboreal individuals with stem diameter ≥10 cm were measured and identified. Multiple regressions we...