Abstract This study aimed to investigate the presence of maternal effect on the inheritance of flax seed coat color. Direct and reciprocal crosses were performed between four yellow flax seed lines and two brown flax seed cultivars. F1 and F2 populations of direct and reciprocal crosses were evaluated for coat color. Four F2 populations were selected for analysis of coat color in the F3 generation. The phenotypic segregation pattern was assessed by the chi-square test. The nuclear genotype of the female parent influenced all F1, F2, and F3 populations. F1 and F2 seeds were always equal to the phenotype of the female parent. F3 populations had a 3:1 ratio of plants producing yellow and brown seeds. The maternal effect resulted from the transfer of gene products from maternal cytoplasm to offspring, with evidence of the effect of a single gene with a dominant allele for the yellow phenotype.

Abstract The objective of this work was to evaluate the performance and yield stability of yellow flax genotypes, as well as to identify the best ones for breeding. Nineteen lines and a local variety were cultivated in the 2018, 2019, and 2020 crop seasons in two environments (municipalities) in the state of Santa Catarina, Brazil. Number of capsules per plant, plant yield, grain yield, and final stand were determined. Data were analyzed across genotypes within each environment and across environments within genotypes. Genotype × environment interactions were evaluated by a joint analysis, in which stability and adaptability parameters were estimated. Correlations between final plant stand and yield components were also estimated. There is a high variability in the productive performance among genotypes. The genotype × environment interactions influenced plant traits. The effect of factors related to soil, climate, and population density on number of capsules and grain weight must be considered. The flax genotypes present high grain yield means in all environments. The analysis of stability and adaptability reveals that genotypes LINPG87 and LINPG88 stand out in productive performance and stability.

Resumo O objetivo deste trabalho foi avaliar o desempenho e a estabilidade produtiva de genótipos de linhaça amarela, bem como identificar os melhores para seleção. Dezenove linhagens e uma variedade local foram cultivadas nas safras de 2018, 2019 e 2020, em dois ambientes (munícipios) no estado de Santa Catarina, Brasil. Foram determinados número de cápsulas por planta, rendimento de plantas, rendimento de grãos e estande final. Os dados foram analisados entre genótipos dentro de cada ambiente e entre ambientes dentro dos genótipos. As interações genótipo × ambiente foram avaliadas por análise conjunta, em que foram estimados os parâmetros de estabilidade e adaptabilidade. Também foram estimadas as correlações entre o estande final de plantas e os componentes da produção. Há alta variabilidade no desempenho produtivo entre os genótipos. As interações genótipo × ambiente influenciaram as características das plantas. Deve-se considerar o efeito de fatores relacionados ao solo, ao clima e à densidade populacional sobre o número de cápsulas e o peso de grãos. Os genótipos de linho apresentam elevados rendimentos médios de grãos em todos os ambientes. A análise de estabilidade e adaptabilidade revela que os genótipos LINPG87 e LINPG88 se destacam em desempenho e estabilidade de produção.

ABSTRACT The photosynthetic metabolism is a key point to improve soybean yield. In this work, we demonstrated that radiation use by soybean plants can be improved, aiming to improve the grain yield in the lower canopy. The objective of this study was to observe whether the increase in solar radiation input in the canopy of soybean plants improves their yield performance. Three experiments were carried out during the 2017/2018 season. For each experiment, treatments consisted in the opening of one or two side rows of cultivation at the R2 and R5 stage of soybean plants (NA5909RR) until maturity, plus a control. Increase on solar radiation provided by the oppening of rows enhanced the yield potential in the nodes of the lower canopy, mainly when two rows were opened. The main benefits of increasing the radiation available throughout the canopy of soybean plants are observed in the number of pods and thousand-grain weight, demonstrating the importance of increasing the availability of assimilates in lower leaves. Interestingly, the benefits of the increase in solar interceptation were observed regardless of the yield potential of the area, which varied between 4.9 and 6.7 ton ha-1.

ABSTRACT. Heterosis has been one of the most studied phenomena since genetic studies were conceived. Knowledge of this phenomenon for the root distribution trait in beans (Phaseolus vulgaris L.) can favour the development of genotypes that are more tolerant to abiotic stresses. This study aimed to verify the occurrence of heterosis for the root distribution trait in hybrid F1 populations of common bean derived from crosses within and between gene groups. Thirty-six populations (six parents and 30 hybrids) were evaluated under field conditions in the agricultural years 2016/17 and 2017/18. The root distribution was assessed with the adapted Bohm method. The genotypes responded similarly to environmental changes (absence of an interaction). However, the root distribution differed significantly between the agricultural years. Comparisons between the mean of hybrids from crosses within each gene pool and the mean of parents did not reveal heterosis. The comparisons between gene groups showed significant differences only between BRS Embaixador x IPR Uirapuru, CBS 14 x IPR Uirapuru, and BAF 53 x IPR Uirapuru and the mean of parents. The absence of heterosis in the root trait can be explained by the degree of kinship between the gene groups, as well as some epistatic interactions.

ABSTRACT Genetic variability is essential for gains in breeding programs. The cyclic process of progeny recombination is a strategy to raise the chances of selecting better genotype combinations. The objective of this study was to identify superior progenies between common bean genes groups in first recurrent selection cycle for root system traits. Parents of the Andean and Middle American gene groups were hybridized in a complete diallel scheme. Thereafter, the parents and F1 and F2 populations were planted in the field. To establish the base population of recurrent selection (C0), seven segregating populations (F2) with superior performance for root system were selected and intercrossed, resulting in recombinant progenies (C1). To estimate the selection gain, the parents and C0 and C1 genotypes were compared with regard to the following variables: total root length (TRL, cm), projected root area (PRA, cm2), root volume (VOL, cm3) and number of root tips (RT). The difference between genotype combinations indicates the presence of genetic variability and effectiveness of recurrent selection. The mean genetic progress for root system-related traits was 12.9% (TRL), 12.6% (PRA), 12% (VOL) and 11.5% (RT) in the first recombination cycle. The mean phenotypic performance of seven of the C1 progenies exceeded that of their parents for all root system traits. These progenies are promising as base populations of the next selection cycle.

ABSTRACT This study was carried on evaluating effects of inoculation with Bacillus species and generations of genetically improved seeds on Pinus taeda growth in nursery conditions. Two experiments, based on distinct inoculation methods (sowing and post-emergence) were performed under a 3 x 2 factorial, completely randomized block design (3 levels of inoculation and 2 levels of genetic improvement of Pinus taeda). Plant height and diameter were measured at different stages along seedling development. At harvest, root volume, root fresh and dry mass, shoot fresh and dry mass and quality index were also estimated. Data were submitted to a two-way analysis of variance (p<0.05) and Tukey´s test was used to separate means (p<0.05). Data from experiment with inoculation at sowing showed that Bacillus amyloliquefaciens improved plant height (20%) and shoot dry mass (28%) of 2.0 generation seedlings compared to control plants. Regarding post-emergence inoculation, plants from 1.5 generation presented more pronounced effects of Bacillus amyloliquefaciens. Overall, inoculated seedlings were 9.8% taller and produced 60% more root dry mass than non-inoculated plants. Regardless of seedling generation, B. amyloliquefaciens increased Dickson Quality Index by 30%. These results suggest that each generation of genetically improved P. taeda has different growth responses to B. amyloliquefaciens. Methods of inoculation, combined with level of genetic improvement, must also be considered to obtain the best benefit to seedling development when using this rhizobacterium. Based on the current findings, inoculation with B. amyloliquefaciens should be incorporated as a silvicultural practice to improve growth of P. taeda under nursery conditions.

RESUMO Quando combinados distintos grupos gênicos por meio de hibridações, é necessário o conhecimento do tipo de ação gênica preponderante na expressão de um caráter. O entendimento dessa informação ampara melhoristas para a tomada de decisões nas etapas de condução e seleção de populações segregantes no decorrer do programa de melhoramento genético. Assim, o objetivo do trabalho foi determinar os efeitos da capacidade de combinação e ação gênica para a característica distribuição radicular dos grupos de feijão Andino e Mesoamericano. Seis genitores de feijão dos grupos andino e mesoamericano foram hibridados em esquema de dialelo completo, resultando em 30 híbridos F1. Os genitores e híbridos foram conduzidos a campo em delineamento látice simples. A característica alvo foi a distribuição das raízes, calculada como a quantidade relativa de raízes no solo superior. O efeito da capacidade geral de combinação foi significativamente maior em relação aos efeitos de capacidade específica de combinação (58%) e efeito recíproco (41%). As estimativas de combinações foram modificadas em função da ordem dos grupos gênicos utilizados. As combinações IPR Uirapuru x BAF53 (mesoamericano x andino), BAF53 x CBS14 (andino x andino) e CBS14 x IPR Uirapuru (andino x mesoamericano) foram as principais responsáveis por incrementar a média da característica distribuição radicular. No entanto, mesmo que realizando combinações entre grupos gênicos, a maior fração da variância genética foi relacionada a componentes aditivos (60%). Consequentemente, a ação gênica aditiva foi predominante na expressão do caráter distribuição radicular em feijão independente do grupo gênico utilizado.

ABSTRACT When different gene groups are combined by hybridization, the expression of predominant genes for a trait must be known. This understanding is fundamental to the decisions made by breeders in the stages of cultivation and selection of segregating populations during the breeding program. Thus, the objective of this study was to determine the effects of combining ability and gene action for the root distribution traits of the Andean and Mesoamerican common bean gene groups. Six common bean parents from the Andean and Mesoamerican groups were hybridized in a complete diallel mating scheme, resulting in 30 F1 hybrids. The parents and hybrids were planted in the field in a simple lattice design. The target trait was root distribution, calculated as the relative number of roots in the topsoil. The effect of the general combining ability was significantly higher than that of the specific combining ability (58%) and the reciprocal effect (41%). Particularly, the combination estimates were modified according to the order of the gene groups used. The combinations IPR Uirapuru x BAF53 (Mesoamerican x Andean), BAF53 x CBS14 (Andean x Andean), and CBS14 x IPR Uirapuru (Andean x Mesoamerican) mainly exhibited an increase in the mean root distribution. However, the highest fraction of genetic variance correlated with additive components (60%), even in crosses involving different gene groups. Consequently, the additive gene action was predominant in the expression of root distribution trait in common bean, irrespective of the gene group used.

RESUMO Dentre as doenças que afetam as lavouras de feijão está a antracnose, causada pelo fungo Colletotrichum lindemuthianum (Sacc. & Magnus), com ocorrência em todo o Brasil, acarretando perdas de até 100 % na produção de grãos. Cerca de 20 genes que conferem resistência a raças específicas do patógeno já foram descritos na literatura. Objetivou-se avaliar as variedades de feijoeiro dos estados de Santa Catarina e Paraná, no que diz respeito à resistência a antracnose, em duas safras. Além disso, duas cultivares comerciais foram utilizadas como controles: IPR Tangará, como suscetível; e BRS Campeiro, como moderadamente resistente. A maioria das variedades locais foi considerada resistente ou moderadamente resistente, sendo mais pronunciada a cultivar Amendoim, com grãos grandes e tegumento vermelho, evidenciando resistência em ambas as avaliações. A este respeito, a possibilidade de utilizá-las como fontes de resistência à antracnose pode ser considerada, pois, também, demonstram adaptabilidade às condições ambientais.

ABSTRACT Anthracnose is an important disease caused by the Colletotrichum lindemuthianum (Sacc. & Magnus) fungus in bean crops. It occurs throughout Brazil and may cause losses of up to 100 % in grain production. About 20 genes that confer resistance to specific races of the pathogen have already been described in the literature. This study aimed to evaluate bean varieties from the Brazilian states of Santa Catarina and Paraná, regarding the resistance to anthracnose, in two cropping seasons. In addition, two commercial cultivars were used as controls: IPR Tangará, as susceptible; and BRS Campeiro, as moderately resistant. The majority of the local varieties was considered resistant or moderately resistant, being more pronounced the Amendoim cultivar, with large grains and red tegument, evincing resistance in both evaluations. Regarding this, the possibility of using them as resistance sources to anthracnose may be considered, since they also show adaptability to the environmental conditions.

RESUMO Redução no ciclo e uniformidade na maturação de frutos são características desejadas para a colheita mecanizada da cultura da mamona. O objetivo do presente trabalho foi estudar o efeito da limitação do crescimento secundário sobre o crescimento e os parâmetros produtivos da mamona. O experimento de campo foi conduzido entre fevereiro e maio de 2012, em delineamento experimental de blocos casualizados e esquema fatorial 2x2, com quatro repetições. Dois híbridos de mamona (Híbrido 12 e Híbrido 18) foram cultivados em duas formas de condução: (i) plantas sem nenhuma limitação ao crescimento e (ii) plantas com limitação do crescimento secundário do caule (poda e desbaste). A limitação do crescimento secundário das plantas resultou em maior partição de assimilados para o racemo primário das plantas, promovendo maior número e massa de grãos. Como resultado, plantas com apenas o racemo primário apresentaram produtividade de grãos equivalente a plantas que cresceram sem limitações. A produtividade de óleo em plantas com apenas o racemo primário foi equivalente a plantas testemunha para o Híbrido 12 e superiores para o Híbrido 18, com a vantagem da obtenção de plantas com maturação uniforme.

ABSTRACT Cycle reduction and uniform fruit maturation are desired characteristics for a mechanical harvest of castor bean crop. The objective of this research was to study the effect of secondary growth limitation on growth and production parameters of castor bean plants. A field experiment was conducted between February and May 2012 in a randomized block design in a factorial scheme 2 × 2, with four replications. Two castor bean hybrids (Hybrid 12 and Hybrid 18) were grown in two cultivation systems: (i) plants without growth limitation and (ii) plants with secondary stem growth limitation (thinning with pruning). Removal of secondary stems resulted in higher partitioning of assimilates to the primary raceme, promoting higher number and dry weight of grains. As a result, plants with only the primary raceme presented grain yield equivalent to plants without growth limitation. Oil yield of plants with only the primary raceme was equivalent to the control for the Hybrid 12 and higher for the Hybrid 18, with advantage of uniform maturation for these plants.

Resumen Objetivo: Reflexionar sobre la transmisión vertical del VIH en el contexto de la promoción de la salud y del cuidado de enfermería. Síntesis del contenido: Documento de reflexión basado en una búsqueda bibliográfica de artículos y publicaciones sobre el tema del Ministério da Saúde do Brasil. Los descriptores utilizados en las búsquedas fueron Transmisión Vertical de Enfermedad Infecciosa, VIH, Promoción de la salud y Educación en salud. En el contexto en que se concibe la promoción de la salud como prevención de enfermedades, las intervenciones de enfermería que participan en el proceso de prevención de la transmisión vertical del VIH son numerosas, las cuales comprenden tanto la atención previa al embarazo de la mujer VIH positiva como la atención prenatal, al parto y postparto del niño expuesto al VIH. Se constató la importancia que revisten las acciones educativas al considerarse factor clave para la promoción de la salud en el contexto de la transmisión vertical del VIH. Cabe resaltar la contribución de las acciones educativas al establecer una relación dialógica entre las enfermeras y las mujeres VIH positivas, cuyo objetivo es el empoderamiento de éstas. Conclusión: El presente documento contribuye a que los enfermeros reflexionen sobre la práctica y realicen un cuidado dedicado a promover la salud en esta población de manera individual, ética y eficaz. El propósito de este tipo de cuidado es abarcar los verdaderos problemas de salud que presentan las mujeres VIH positivas y asegurarles una atención integral, humanizada y decisiva de acuerdo con sus características específicas.

Abstract Objective: To reflect about vertical transmission of HIV in the context of health promotion and nursing care. Summary of content: This is a reflection paper based on a literature search of articles and publications for the subject of Ministério da Saúde do Brasil. The following descriptors were used: Infectious Disease Transmission, Vertical, HIV, Health Promotion and Health Education. Within the context in which health promotion is conceived as disease prevention, there are several nursing interventions involved in the prevention of vertical transmission of HIV process, encompassing both pre-pregnancy caring for the HIV-positive woman and prenatal, delivery, and postpartum caring for the HIV-exposed child. It was found that educational actions are of vital importance to promotion of health in the context of the vertical transmission of HIV, in as much as they contribute to establish a dialogical relation between nurses and HIV-positive women, which aims to empower them. Conclusion: This paper contributes to nurses to reflect about their practice and to carry out care functions in order to promote health of this public in individual, ethical, and effective manner. This sort of care must cover actual health issues of HIV-positive woman, ensuring them integral, humanized, and determining care, in accordance with their own specific conditions.

Resumo Objetivo: Refletir sobre a transmissão vertical do HIV na conjuntura da promoção da saúde e do cuidado de enfermagem. Síntese do conteúdo: Trata-se de um documento de reflexão, embasado em uma busca na literatura científica e em publicações do Ministério da Saúde do Brasil sobre o tema, com os descritores: Transmissão Vertical de Doença Infecciosa, HIV, Promoção da Saúde e Educação em Saúde. No âmbito da concepção de promoção da saúde como prevenção de doenças, diversas são as intervenções de enfermagem envolvidas no processo de prevenção da transmissão vertical do HIV, abrangendo desde cuidados que antecedem a gravidez da mulher soropositiva, passando pelo pré-natal, parto, puerpério e cuidados com a criança exposta ao HIV. Verificou-se a importância das ações educativas como um dos principais elementos para a promoção da saúde no contexto da transmissão vertical do HIV, por contribuírem para o estabelecimento de uma relação dialógica entre enfermeiros e mulheres soropositivas, levando ao seu empoderamento. Conclusão: Este documento contribui para que o enfermeiro reflita acerca da sua práxis e busque realizar seu cuidado com vistas à promoção da saúde desse público de forma diferenciada, individualizada, ética e efetiva, no intuito de abordar seus reais problemas de saúde e garantir um cuidado holístico, humanizado e resolutivo para essa clientela, que tem características específicas.

RESUMO O cultivo de mamona sob altas densidades populacionais pode aumentar a produtividade devido à maior interceptação de luz e à redução dos drenos vegetativos. O objetivo desta pesquisa foi avaliar o efeito da densidade populacional de híbridos de mamona sobre o crescimento das plantas. O experimento foi conduzido em Botucatu, SP, em 2011 e 2012. O delineamento experimental utilizado foi de blocos ao acaso organizado em parcelas subdivididas com quatro repetições. As parcelas foram constituidas pelas coletas e as subparcelas foram constituídas por um fatorial 3x3. O primeiro fator foi composto por três genótipos e o segundo fator por três densidades populacionais. As variáveis analisadas foram matéria seca de folhas, caules, racemos e matéria seca total, realizadas ao 30, 60, 90, 120 e 150 dias após a emergência (DAE). Os dados foram submetidos à análise de variância pelo teste F (p < 0,05). Quando houve interação entre os fatores e coleta as médias foram analisadas por regressão (p < 0,05). O crescimento foi maior no ano de 2012 devido à maior disponibilidade hídrica. Em 2011, sob menor pluviosidade, houve menor ramificação resultando em fechamento do ciclo, com perda total das folhas nos híbridos. Altas densidades populacionais suprimem parcialmente o desenvolvimento de estruturas de ordem superiores, principalmente quando associadas à restrições hídricas.

ABSTRACT Castor bean grown at high plant densities can increase yield due to increased light interception and reduction in sink demand. The objective of this study was to evaluate the effect of plant density on growth of castor bean hybrids. The experiment was conducted in Botucatu, SP, Brazil, in a split plot randomized block design, with four replications, in 2011 and 2012. The main plot consisted of the sampling times and the subplots consisted of a 3x3 factorial, with the 3 genotypes in the first factor and the 3 plant densities in the second factor. The variables analyzed were: dry mass of leaves, stems, racemes, and total dry matter, which were measured at 30, 60, 90, 120 and 150 days after emergence (DAE). Data were examined for significant differences using analysis of variance followed by the F test (p < 0.05). When interaction was found between the factors and sampling the means were analyzed by regression analysis (p < 0.05). Growth performance was higher in 2012 because of the greater water availability. In 2011, under lower rainfall, there was less branching resulting in cycle end, with total leaf loss. High plant densities partially suppress the development of higher-order structures, especially when associated with water restriction.

OBJECTIVES: To evaluate the colorimetric change in incisors and canines of adolescents aged 12 to 20 years submitted to at-home whitening and to evaluate satisfaction, sensitivity and discomfort during the procedures through a questionnaire. METHOD: Thirty adolescents were randomly assigned to the following groups: 1) 6.0% hydrogen peroxide (White Class with calcium - FGM); 2) 7.5% hydrogen peroxide (White Class with calcium - FGM); 3) 10% hydrogen peroxide (Oral B 3D White - Oral-B); 4) Control group - placebo. Assessments were performed prior to treatment as well as at 7, 30, 180 and 360 days after treatment. Friedman’s ANOVA was used to analyze color. The Kruskal-Wallis test followed by Dunn’s post hoc test was used to compare the groups at the different evaluation times. Answers on the questionnaires were ranked, and non-parametrical tests were employed. The groups were compared in each period using the Kruskal-Wallis test followed by the Student-Newman-Keuls test. Categorical data were analyzed using Fisher's exact test, and the Wilcoxon test was used for the analysis of different periods. P-values were corrected using the Hyan-Holm step-down Bonferroni procedure. Clinicaltrials.gov: NCT01998386. RESULTS: Similar results were obtained one month after treatment with both tooth whitening gels and whitening strips. Patients were partially satisfied with the treatment after the first and second weeks and would recommend it. All products demonstrated color stability after 12 months of follow-up. CONCLUSIONS: The bleaching procedure was efficient, and the patients could perceive its result. Further investigations are needed to determine the effects of bleaching on young teeth.

RESUMO A depressão por endogamia em plantas, causada por autofecundação ou cruzamento entre plantas com alto grau de parentesco, é um fenômeno genético que afeta os caracteres quantitativos. Objetivou-se verificar a ocorrência de depressão por endogamia em progênies de crambe originadas de autofecundação, em comparação com progênies de polinização livre. O delineamento experimental foi em blocos casualizados, com três repetições, em esquema fatorial 32 x 2, em que foram avaliadas 32 progênies de crambe sob dois sistemas de reprodução (autofecundação artificial e polinização livre). Foram avaliados a produtividade de grãos, massa de 1.000 grãos, altura de planta e estande final. Observou-se interação significativa entre progênies e sistemas de reprodução para todas as características avaliadas. Para a maioria das progênies, houve redução na produtividade de grãos, massa de 1.000 grãos e altura de plantas oriundas de autofecundação, em comparação com as progênies de polinização livre. Houve depressão por endogamia para todas as características avaliadas, especialmente para a produtividade de grãos. Os coeficientes de herdabilidade para as progênies oriundas de autofecundação foram maiores do que para as de polinização livre, exceto para massa de 1.000 grãos.

ABSTRACT Inbreeding depression in plants, caused by selfing or crossing among plants with a high degree of relatedness, is a genetic phenomenon that affects quantitative traits. This study aimed at verifying the occurrence of inbreeding depression in crambe progenies originated from selfing, in comparison with open pollination progenies. A randomized blocks design, with three replications, in a 32 x 2 factorial arrangement, with 32 crambe progenies and two reproduction systems (artificial selfing and open pollination), was used. Grain yield, 1,000-grain weight, plant height and final stand were evaluated. A significant interaction was observed between progenies and reproduction systems in all traits evaluated. A reduction in grain yield, 1,000-grain weight and plant height occurred in the majority of the selfing progenies, when compared to open pollination progenies. Inbreeding depression was observed in all traits, especially for grain yield. The heritability coefficients of selfed progenies were higher than the open pollinated ones, except for 1,000-grain weight.

Abstract The objective of this study was to estimate the genetic variability of a Brazilian cultivar of crambe, as well as to estimate the genetic gain, with selection focusing on grain yield in crambe. Eighty two progenies were selected within the FMS Brilhante cultivar in 2009. The progenies were evaluated in 2010 and 2011 in Botucatu and São Manuel, Sao Paulo State, with the FMS Brilhante used as control. Great genetic variability was verified in all of the characteristics studied. Significant interactions of progenies x location and progenies x year were observed based on the joint analysis. The genetic gain for the grain yield ranged from 9.3 to 48.9% on the individual analysis and ranged from 6.6 to 21.4% on the joint analysis. The selection used in the base plant population of FMS Brilhante was efficient to increase grain yield in crambe.

RESUMO A cultura da mamona possui grande potencial para o cultivo em condições brasileiras, contudo, deve-se buscar métodos cada vez mais eficientes de manejo da cultura, a fim de atingir altas produtividades e introduzir de modo definitivo a cultura no sistema agrícola nacional. O objetivo do presente estudo foi avaliar as características agronômicas e a produtividade da mamoneira em função do método de condução de plantas e da densidade de cultivo. O estudo foi conduzido em condições de campo no ano agrícola de 2010, utilizando a cultivar IAC 2028, em delineamento experimental de blocos casualizados em esquema fatorial 2x3 com quatro repetições. O primeiro fator foi composto por duas densidades de semeadura (26666 e 111111 plantas ha-1), enquanto o segundo fator foi composto por três métodos de condução de plantas (testemunha, poda parcial e poda+desbrota). Ao final do desenvolvimento da cultura, foram determinadas as características agronômicas das plantas, os componentes da produção e a produtividade. A poda + desbrota proporcionou melhoria dos caracteres agronômicos, sem afetar a produtividade e reduziu o ciclo da cultura em até 30 dias. Este comportamento, aliado à maturação uniforme, pode proporcionar a colheita mecanizada da cultura, além de proporcionar o cultivo da mamoneira em janelas de cultivo na safrinha, sem prejudicar a implantação da safra seguinte. O cultivo adensado de plantas de mamona limitou a emissão de ramos produtivos secundários sem afetar a produtividade, revelando elevada plasticidade fenotípica no desenvolvimento da cultura.

ABSTRACT The castor bean shows great potential for cultivation under the conditions found in Brazil, however, in order to achieve high productivity and introduce the crop into the Brazilian agricultural system, ever more efficient methods of crop management should be developed. The aim of this study was to evaluate the agronomic characteristics and productivity of the castor bean for the method of cultivation and planting density. The study was carried out under field conditions during the 2010 crop year, using the IAC 2028 cultivar. An experimental design of randomised blocks was employed in a 2 x 3 factorial, with four replications. The first factor comprised two planting densities (26,666 and 111,111 plants ha-1), while the second factor consisted of three methods of cultivation (control, partial pruning and thinning with pruning). At the end of crop development, the agronomic characteristics of the plants, yield components and productivity were determined. Pruning with thinning resulted in an improvement in the agronomic characteristics without affecting productivity, and reduced the crop cycle by 30 days. This behaviour, together with uniform maturation, may contribute to the mechanical harvesting of the crop, as well as allowing cultivation of the castor bean in the off-season without affecting the following harvest. Dense cultivation of the castor bean limited the appearance of secondary productive branches without affecting productivity, demonstrating a high phenotypic plasticity in crop development.