ABSTRACT In the initial phase of the coffee crop, the control of weeds and water availability for the establishment of the plants is a concern. The polyethylene cover can positively influence the chemical and biological characteristics of the soil and, consequently, the root system. The objective of this work was to evaluate the morphology of the root system of coffee plants using polyethylene mulching of different widths and colors. Coffee was planted in December 2016 using the cultivar Topázio MG-1190. A randomized repetitions design was used, with four blocks and five treatments, as follows: 1.20-m wide white/black mulching, 1.40-m white/black mulching, 1.20-m silver/black mulching, 1.40-m silver /black mulching, and no mulching. Total root dry matter per soil volume, total root length per soil volume, total root volume per soil volume, total root area per soil volume, specific root surface, specific root length, and mean root diameter were all evaluated. Roots with smaller diameters were concentrated in the 0-0.20 m depth layer, while in the 0.20-0.40 m depth layer, roots with larger diameters were found. Plants grown in 1.20-m silver/black mulching showed a greater surface area and a specific length of the roots.

ABSTRACT Remote monitoring of the management of coffee crops is necessary as the demand in decision-making, where the aim is to rise production based on sustainable management is in a constant growth. In this work, it was evaluated the potential of images obtained by low-cost sensors in the discrimination of sources and doses of mineral and organomineral fertilizers in coffee. The experimental design was in randomized blocks, with five blocks and six treatments, as follows: (T1) - 100% of the organomineral treatment; (T2) - 70% of the organomineral treatment; (T3) - 50% of the organomineral treatment; (T4) - 100% of mineral fertilization; (T5) - standard treatment of the farm and (T6) - 70% of mineral fertilization. After management, we used the Mapir 3 Survey3W camera coupled to an ARP drone – Phantom4 to take images of the experiment over a 12-month vegetative period. Combined with image taking, it was collected agronomic parameters of coffee growth and productivity for two crops and concluded that different fertilization doses did not significantly affect the analyzed parameters. Based on the supervised classification of multispectral images, it was possible to discriminate treatments with a higher degree of accuracy (86.66% accuracy) than when analyzing coffee growth parameters.

RESUMO Informações da variação de importantes características morfológicas e fisiológicas do quiabo são limitadas. A análise molecular é uma ferramenta adicional importante nos estudos de caracterização de germoplasma. O estudo teve como objetivo avaliar o desempenho do crescimento e da produção de 20 acessos pré-comerciais de quiabo para identificar a associação de marcadores moleculares com características morfológicas. Dezenove caracteres morfológicos foram medidos com cinco descritores qualitativos e 14 quantitativos. Para a análise dos padrões genéticos, foram utilizados marcadores RAPD com nove primers e 24 bandas utilizáveis. A dissimilaridade genética foi avaliada com base em matrizes morfológicas e genéticas. Além disso, a representação gráfica das distâncias genéticas foi realizada pelo método UPGMA e otimização de Tocher. A caracterização morfológica dos acessos detectou polimorfismo para todas as características avaliadas. Os marcadores RAPD foram eficientes na detecção da variabilidade genética entre os acessos de quiabo. Para os primers usados no experimento, apenas OPE10 não amplificou a fita de DNA. Os outros oito primers produziram um total de 35 bandas, sendo 25 polimórficas e dez monomórficas. Os caracteres morfológicos e marcadores moleculares identificaram ampla variabilidade genética entre os 20 acessos de quiabo, indicando a possibilidade de cruzamentos bem-sucedidos em programas de melhoramento e o isolando genótipos interessantes. As análises morfológica e molecular foram complementares e auxiliaram na seleção dos genótipos. A análise molecular indicou alguns acessos divergentes que não foram encontrados na análise morfológica, o que poderia destacar alguns materiais que apresentam uma característica desejável, sendo interessantes para detectar características de dificil mensuração em campo.

ABSTRACT Information of the variation for important morphological and physiological traits of okra is still limited. Molecular analysis is an important additional tool in germplasm characterization studies. The study aimed to evaluate the performance of the growth and yield of 20 pre-commercial okra accessions to identify molecular markers’ association with morphological traits. Nineteen morphological traits were measured with five qualitative and 14 quantitative descriptors. For analysis of genetic patterns Random Amplified Polymorphic DNA (RAPD) markers were used with nine primers and 24 usable bands. The genetic dissimilarity was evaluated based in morphological and genetic matrices. Also, graphical representation of genetic distances was obtained by UPGMA and Tocher’s optimization method. The morphological characterization of the accessions detected polymorphism for all evaluated traits. RAPD markers were efficient in detecting genetic variability among okra accessions. For the primers used in the experiment, only OPE10 did not amplify the DNA strand. The other eight primers produced a total of 35 bands, in which 25 were polymorphic and ten were monomorphic. The morphological traits and molecular markers identified wide genetic variability among the 20 okra accessions, indicating successful crosses in breeding programs and isolating some interesting materials. Morphological and molecular cluster analyses were complementary and helped in the genotype selection. Molecular analysis indicated some divergent accessions that were not found in morphological analysis, which could highlight some materials that have a desirable trait, that is difficult and highly costly to access in field experiments.

ABSTRACT Stenoma catenifer is considered the main pest of avocado, making impossible to commercialize the infested fruits. This study was conducted with the objective of evaluating the potential of Heterorhabditis amazonensis MC01 in the field control of avocado borer, as well as the nematode release method. Two treatments were tested, namely: release of dead Tenebrio molitor infected with the nematode and hydraulic nematode spraying; hydraulic application of chemical insecticides was used as a control. The experiment was set up in a randomized complete block design with 15 replicates. The concentration of suspension distribution was 5,500 infective juveniles per m2. At the experimental area traps with sex pheromone were installed to capture adult males. The number of borer fruits was evaluated in the two central plants of each plot, sampling 4 fruits per plant. There was a reduction in the percentage of borer fruits from 15 days of application for all control methods. After the release of nematodes, the adult population was similar to the control, and it can be inferred that, even without chemical control, there was no increase in the number of adults. Thus, H. amazonensis was considered promising under field conditions, reducing the populations of S. catenifer, in all release methods.

RESUMO O cultivo de Piper aduncum para a extração de óleo essencial é crescente, mas carece de informações básicas de manejo e cultivo, que possibilitem produtividade e qualidade do produto para atender a demanda de mercado. Objetivou-se avaliar a relação entre a produção de óleos essenciais em P. aduncum e tensões de água no solo (20 kPa, 40 kPa, 60 kPa, 100 kPa e sem irrigação). Foram avaliados o número de idioblastos e a produção de óleo essencial em folhas de plantas cultivadas. A variação na tensão de água no solo altera a quantidade de idioblastos nas folhas de P. aduncum, com reflexo na produção de óleo essencial. A tensão de água no solo de 20-60 kPa é suficiente para a planta expressar o maior número de idioblastos e maior produção de óleo essencial. A espécie se adapta a diferentes condições de disponibilidade de água no solo. Em condições de estresse, devido ao déficit ou excesso de água, a produção de óleo essencial é reduzida.

ABSTRACT The growing of Piper aduncum for essential oil extraction has increased, but there is a lack of basic information about its management and cultivation, which allows the productivity and quality of the oil, in order to attend the market demands. This study aimed to evaluate the relation between the production of essential oils from P. aduncum and soil water pressure heads (20 kPa, 40 kPa, 60 kPa, 100 kPa and non-irrigated). The assessment comprised the quantification of idioblasts and the production of essential oil extracted from leaves of cultivated plants. The variation in the soil water pressure head alters the amount of idioblasts in P. aduncum leaves, with impacts on the essential oil production. A soil water pressure head range of 20-60 kPa is sufficient for this species to express the highest amount of idioblasts and the highest level of essential oil production. The species adapts itself to different water availability conditions in the soil. Under stress conditions, due to water deficit or excess, the production of essential oil is reduced.

Resumo: A qualidade do ajuste e eficiência de modelos de germinação foram comparadas. Modelos Lineares Generalizados (MLGs) foram executados com o componente aleatório correspondendo ao percentual de germinação para a distribuição normal e o número de sementes germinadas para a distribuição binomial. Baixos valores do Critério de Informação de Akaike (AIC) e do Critério de Informação Bayesiano (BIC), ajuste aos envelopes simulados dos Normal plots e intervalos de confiança corretos para as médias justificam a importância do uso dos MLGs com distribuição binomial. Alguns autores criticam o uso inapropriado da análise de variância (ANOVA) para dados discretos como a germinação de copaíba, mas todas as pressuposições do modelo foram atendidas, mesmo a espécie possuindo sementes dormentes e germinação irregular.

Abstract: We compared the goodness of fit and efficiency of models for germination. Generalized Linear Models (GLMs) were performed with a randomized component corresponding to the percentage of germination for a normal distribution or to the number of germinated seeds for a binomial distribution. Lower levels of Akaikes’s Information Criterion (AIC) and Bayesian Information Criterion (BIC) combined, data adherence to simulated envelopes of normal plots and corrected confidence intervals for the means guaranteed the binomial model a better fit, justifying the importance of GLMs with binomial distribution. Some authors criticize the inappropriate use of analysis of variance (ANOVA) for discrete data such as copaiba oil, but we noted that all model assumptions were met, even though the species had dormant seeds with irregular germination.

ABSTRACT Statistical analysis is considered an important tool for scientific studies, including those on seeds. However, seed scientists and statisticians often disagree on the nature of variables addressed in germination experiments. Statisticians consider the number of germinated seeds to be a binomially distributed variable, whereas seed scientists convert it into a percentage and often analyze it as a normally distributed variable. The requirement for normal adjustment restricts the models of analysis of variance that can be used. Lack of fit requires nonparametric tests, but they are known by their inferential problems. Generalized Linear Models (GLM) can provide better fit to germination variables for any species, including Lychnophora ericoides Mart., because they allow wider probability distributions with fewer requirements. Here we suggest the use of relative germination besides absolute germination for species with seed development problems, such for L. ericoides and others from the campos rupestres. This paper introduces the most current statistical advancements and increases the possibilities for their application in seed science research.

RESUMO. O objetivo desse estudo foi avaliar a influência da polinização por abelhas na produtividade de canola em diferentes híbridos comerciais, Hyola 61 e Hyola 433, em Minas Gerais. Os estudos foram conduzidos na Fazenda Experimental Água Limpa da Universidade Federal de Uberlândia. Para avaliar os efeitos da polinização de abelhas na produtividade nas sementes de canola, realizou-se um experimento com exclusão dos visitantes florais, comparando a produção em quatro tratamentos: (a) autogamia em Hyola 61 e (b) autogamia em Hyola 433; (c) polinização aberta em Hyola 61 e (d) polinização aberta em Hyola 433 com acesso livre de insetos. As flores disponíveis para polinização apresentaram 25% e 18,8% sílicas mais pesadas e 22,5% e 20,6% mais sementes por sílica em Hyola 61 e Hyola 433, respectivamente, do que aquelas privadas de polinização. Os resultados apontaram que o processo de polinização cruzada, favorecida pela visita de insetos polinizadores, influenciou positivamente alguns parâmetros relacionados a produção, demonstrando-se vantajosa em relação à autogamia da canola no Cerrado Mineiro.

ABSTRACT. The objective of this study was to evaluate the influence of pollinating insects on canola productivity for different commercial hybrids, Hyola 61 and Hyola 433, in Minas Gerais State, Brazil. The studies were conducted at the Fazenda Experimental Água Limpa of the Federal University of Uberlândia. To evaluate the influence of pollination by bees on the production of canola seeds, an experiment was carried out to exclude floral visitors and compare canola seed production following four treatments: (a) autogamy in Hyola 61, (b) autogamy in Hyola 433, (c) open pollination in Hyola 61, with insects having free access, and (d) open pollination in Hyola 433, with insects having free access. Flowers that were available for pollination had 25% and 18.8% heavier pods and 22.5% and 20.6% more seeds per pod in Hyola 61 and Hyola 433, respectively, than those bagged without pollination. The results show that the cross-pollination process, fostered by pollinator visits, positively influenced some parameters related to production, presenting an advantage in relation to canola autogamy in Cerrado Mineiro.

RESUMO: Os nematoides entomopatogênicos (NEPs) são eficazes contra insetos de solo e têm sido usados em sistemas agrícolas. A ação de NEPs sobre grilos (Gryllus L.) (Orthoptera: Gryllidae) foi avaliada em condições de laboratório e campo, a fim de selecionar populações para aplicação em área de cultivo. Foram realizados testes de virulência com Heterorhabditis amazonensis RSC05, H. amazonensis MC01, Steinernema carpocapsae All (Weiser) e H. amazonensis GL, assim como verificadas a adequação da concentração de juvenis infectantes (100, 200, 400 e 600 juvenis infectantes por inseto) e a preferência alimentar sem chance de escolha e com chance de escolha, além do teste de campo utilizando armadilhas para amostragem dos insetos. Verificou-se que todos os isolados causaram mortalidade em Gryllus sp. selecionando-se H. amazonensis MC01 e S. carpocapsae All e que o aumento na concentração de juvenis infectantes resultou em mortalidade crescente dos insetos. Com relação aos testes de preferência alimentar, observou-se que, após 16 horas, não houve alimentação em nenhum dos tratamentos. Nos tratamentos com chance de escolha, constatou-se que houve alimentação dos grilos, independentemente da presença ou não de nematoides. Nos testes de campo, antes da aplicação de juvenis infectantes, foram encontrados 19 grilos vivos nas armadilhas, e após a aplicação dos NEPs em suspensão aquosa foram encontrados 2 grilos vivos. Dessa forma, concluiu-se que H. amazonensis MC01 foi promissor no controle de Gryllus sp. nas condições testadas.

ABSTRACT: Entomopathogenic nematodes are effective in controlling soil insects and they are used in agricultural systems. The virulence of entomopathogenic nematodes on crickets (Gryllus L.) (Orthoptera: Gryllidae) was evaluated under different conditions in order to select populations for application in the field. Virulence tests with Heterorhabditis amazonensis RSC05, H. amazonensis MC01, Steinernema carpocapsae All (Weiser) and H. amazonensis GL were performed. Evaluations were then made of the concentrations of infective juveniles (100, 200, 400 and 600 infective juveniles per insect); feeding preference with or without choice; and field tests using traps to evaluate insect sampling. All isolates were found to cause mortality in Gryllus sp., and H. amazonensis MC01 and S. carpocapsae All were selected; an increase in concentration resulted in increased insect mortality. Regarding the feeding preference tests, after 16 h there was no feeding in any of the treatments. In treatments with a chance of choice, it was verified that the crickets fed, independently of the presence of the nematodes. In the field tests, 19 live crickets were found in the traps, and, after application of entomopathogenic nematodes in aqueous suspension, 2 live crickets were found. Results suggested that H. amazonensis MC01 was promising in the control of Gryllus sp. under the tested conditions.