Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is one of the most economically important crop diseases, but is only treatable with fungicides, which are becoming less effective owing to the emergence of fungicide resistance. There are no commercial soybean cultivars with durable resistance to P. pachyrhizi, and although soybean resistance loci have been mapped, no resistance genes have been cloned. We report the cloning of a P. pachyrhizi resistance gene CcRpp1 (Cajanus cajan Resistance against Phakopsora pachyrhizi 1) from pigeonpea (Cajanus cajan) and show that CcRpp1 confers full resistance to P. pachyrhizi in soybean. Our findings show that legume species related to soybean such as pigeonpea, cowpea, common bean and others could provide a valuable and diverse pool of resistance traits for crop improvement.

Plant-parasitic nematodes are one of the limiting factors for soybean production worldwide. Overall, plant-parasitic nematodes alone cause an estimated annual crop loss of $78 billion worldwide and an average crop yield loss of 10-15%. This imposes a challenge to sustainable production of food worldwide, since there has been increasing demand for food supply and food security. Unsustainable cropping production systems with monocultures, intensive use of soils and expansion of crops to newly opened areas have intensified problems associated with new pests and diseases. Thus, finding and applying sustainable methods to control diseases associated with soybean are in current need. Over hundred nematode species, comprising fifty genera, have been reported in association with soybean. Of these, the root-knot nematode Meloidogyne spp., cyst nematode Heterodera glycines, lesion nematode Pratylenchus brachyurus and the reniform nematode Rotylenchulus reniformis are major nematode species limiting soybean production. Here, we report an up-to-date literature review on the biology, symptoms, damage and control methods used for these nematodes species. Additionally, unusual and emergent nematode species affecting soybean are discussed.

Euterpe precatoria Mart. has been demanded due to the functional characteristics of its fruits and, therefore, its planting has been encouraged. However, there is a lack of information about the seedling production system of this palm tree. Neither a favorable environment nor the amount of fertilizer in the substrate have been defined for the production of healthy and vigorous seedlings. This study aimed to evaluate the effect of environments and doses of a slow-release fertilizer on the production of E. precatoria seedlings. The experiment was conducted in a randomized block design, with three replications and ten plants per plot. The treatments were arranged in a 4 x 5 factorial scheme, with four environments (under shading levels of 20 %, 30 %, 50 % and 75 %) and five doses of a slow-release fertilizer (0.0 kg m-3, 2.5 kg m-3, 5.0 kg m-3, 7.5 kg m-3 and 10.0 kg m-3 of substrate). The seedling height; root collar diameter; number of leaves; leaf, shoot, root and total dry mass; and the Dickson quality index were analyzed. There were significant interactions between the shaded environments and slow-release fertilizer doses for all the analyzed variables. The 75 %-shaded environment yielded better quality seedlings. The slow-release fertilizer can be used to produce E. precatoria seedlings in environments under shading levels of 50 % and 75 %, being the 4.60 kg m-3 and 8 kg m-3 doses, respectively, the most recommended ones.

The availability of single assai palm (Euterpe precatoria) seedlings with good quality is a fundamental requirement to expand the cultivation of the species. This study aimed to assess the use of fruit agro-industry residues as substrate for producing single assai seedlings. The experiment was carried out under nursery conditions, in a completely randomized design, with four replications and eight plants per plot. Fifteen treatments were evaluated: a commercial substrate, four dry and crushed agro-industrial residues (Brazil nut shell, acerola pit, assai pit and cupuassu peel) and ten combinations of these materials in the proportion of 1:1. The following variables were also measured: shoot height; stem diameter; number of leaves; shoot, root and total dry mass; and Dickson Quality Index score. The substrate formulated with Brazil nut shell + acerola pit stood out for promoting a higher growth and dry biomass, resulting in seedlings with a better quality. The pure assai pit residue was not efficient for producing seedlings, but it showed a good potential when mixed in equal proportion with other materials (e.g. Brazil nut shell and cupuassu peel).

The characterization and evaluation of banana genotypes (Musa spp.) is an important step both for breeding programs and for indication to farmers. Thus, the objective of this work was to evaluate banana genotypes in Rio Branco-Acre, aiming at their incorporation into the region 's production systems. The experiment was carried out in a randomized complete block design in a subdivided plots scheme with five replicates and four plants per plot. The treatments of the plots were the three production cycles, and the subplots were the nineteen banana genotypes. We evaluated plant's height; perimeter of the pseudostem base; number of active leaves at the inflorescence and harvesting stage; the period from planting until flowering, the period from flowering until harvest and period from planting until harvest; the mass of the bunch, the total number of fruits per bunch; the number of pieces; productivity. The genotypes Thap Maeo, FHIA-02, FHIA-18, and Maravilha, present the best agronomic performance and have the potential to be incorporated into the banana production system in the edaphoclimatic conditions of the Rio Branco, Acre region.

Anthracnose (Colletotrichum gloeosporioides) is the main disease affecting single assai palm seedlings and, therefore, a limiting factor to the production of quality seedlings. So far, there are no fungicide recommendations for the control of C. gloeosporioides in Euterpe precatoria. Thus, this study aimed to investigate the action of fungicides, such as pyraclostrobin + fluxapyroxad, as a possible alternative for controlling anthracnose in single assai palm seedlings. The experiment was installed in the nursery at Embrapa Acre, in a randomized block design, with seven treatments (0 – 0.155 – 0.187 – 0.218 – 0.250 – 0.281 – 0.312 μl of fungicide), with four replications of five plants. Evaluations were conducted for ten months regarding seedling height, stem diameter, number of leaves, shoot dry mass, root dry mass, total dry mass, and Dickson Quality Index. A visual scale ranging from 1 to 9 was used to assess the severity of the disease. The data were submitted to analysis of variance and regression analysis. Under the study conditions, the application of the active ingredient pyraclostrobin + fluxapyroxad reduced anthracnose severity by an average of 36.94% in single assai palm, providing better quality seedlings in the nursery.

Espécies de Paspalum são importantes constituintes nas pastagens nativas de regiões tropicais e subtropicais das Américas. Paspalum vaginatum é nativo de áreas litorâneas no Brasil e é amplamente utilizado em campos de golfe nos Estados Unidos devido sua robustez e tolerância a estresses abióticos como a seca, encharcamento e salinidade. Bactérias localizadas no interior dessa espécie vegetal (endofíticas) podem ser parcialmente responsáveis pela tolerância a essas condições extremas. O uso de bactérias capazes de promover o crescimento vegetal como inoculantes é uma estratégia ecologicamente correta para substituir os fertilizantes químicos e melhorar a produção vegetal. Este estudo objetivou isolar e avaliar o potencial de solubilização de fosfato inorgânico (SFI), fixação biológica de nitrogênio (FBN), produção de ácido 3-indolacético (AIA) e potencial antagônico contra fitopatógenos de bactérias endofíticas associadas a P. vaginatum. As bactérias foram isoladas de raízes e folhas de P. vaginatum e testadas in vitro para FBN, SFI, produção de AIA e antagonismo contra o fungo fitopatogênico Bipolaris sp.. Entre os 72 isolados bacterianos testados, 43 fixaram nitrogênio (59,7%), 28 solubilizam fosfato inorgânico (38,9%), 70 produziram AIA (97,2%), mesmo que em baixa quantidade, e 12 apresentaram potencial antagônico contra Bipolaris sp. (16,7%). As 24 bactérias com melhores resultados nos testes foram identificadas por sequenciamento do gene 16S rDNA. Os gêneros identificados foram Bacillus sp., Pantoea sp., Enterobacter sp., Agrobacterium sp., Pseudomonas sp., Staphylococcus sp. e Streptomyces sp..

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