Information about the response of onion to different potassium doses may contribute to optimizing the use of fertilizers and, consequently, make the activity more profitable and environmentally sustainable. In this context, the aim of this study was to evaluate the effects of doses of potassium on onion yields. Two field experiments were carried out in the periods of September to December 2012 and April to July 2013. The experimental design used was completely randomized blocks with four replications. The treatments corresponded to the potassium doses (0, 36, 72, 108, 144 and 180 kg ha-1 of K2O). Potassium fertilization promoted an increase in the content of K in the leaf, commercial and total yield, with the maximum obtained in the dose of 180 kg ha-1 of K2O. The maximum overall and commercial yields were respectively 54.69 and 54.12 t ha-1 in the experiment of September to December 2012 and 47.39 and 46.39 t ha-1 in that of April to July 2013.

ABSTRACT Information about the response of onion to different potassium doses may contribute to optimizing the use of fertilizers and, consequently, make the activity more profitable and environmentally sustainable. In this context, the aim of this study was to evaluate the effects of doses of potassium on onion yields. Two field experiments were carried out in the periods of September to December 2012 and April to July 2013. The experimental design used was completely randomized blocks with four replications. The treatments corresponded to the potassium doses (0, 36, 72, 108, 144 and 180 kg ha-1 of K2O). Potassium fertilization promoted an increase in the content of K in the leaf, commercial and total yield, with the maximum obtained in the dose of 180 kg ha-1 of K2O. The maximum overall and commercial yields were respectively 54.69 and 54.12 t ha-1 in the experiment of September to December 2012 and 47.39 and 46.39 t ha-1 in that of April to July 2013. | RESUMO Informações sobre a reposta da cebola a diferentes doses de potássio podem contribuir para a otimização do uso de fertilizantes e, consequentemente, tornar a atividade mais rentável e ambientalmente sustentável. Nesse contexto, o objetivo do trabalho foi avaliar os efeitos de doses de potássio na produtividade da cebola. Para isso dois experimentos de campo foram realizados nos períodos de setembro a dezembro de 2012 e abril a julho de 2013 O delineamento experimental foi em blocos casualizados completos com quatro repetições. Os tratamentos corresponderam às doses de potássio (0, 36, 72, 108, 144 e 180 kg ha-1 de K2O). A adubação potássica promoveu aumento do teor de K na folha, produtividade comercial total, com o máximo obtido na dose de 180 kg ha-1 de K2O. As produtividades máximas totais e comerciais foram respectivamente de 54,69 e 54,12 t ha-1 no experimento de setembro a dezembro de 2012 e 47,39 e 46,39 t ha-1 de abril a julho de 2013.

The present study aimed at assessing the influence of physical properties associated with soil structure on the Srelative index. Two soil conditions under Ficus carica L. cultivation were studied (with or without liquid bovine biofertilizer in the irrigation water), in the 0-0.1 m and 0-0.3 m layers. Disturbed and undisturbed soil samples were collected from the above-mentioned layers and physical analyzes, pertinent to the study objective, were performed. The response function model was applied to verify how the soil independent physical variables influence on the Srelative index in the 0-0.1 m and 0-0.3 m layers, with 0 and 60% biofertilizer, being combined two to two. Once the response functions were known, the slopes of both functions were compared, being represented by the coefficients β11-β12 and β21-β22. This comparison enabled verifying whether there was an effect of the treatments on the response variable. In addition, the standard error of the difference between coefficients was calculated, and the Student's t-test applied. The method of multiple regression was also used to confirm the effect of the variables on the Srelative index for the 0-0.3 m layer in both treatments. Then, the variables with greater weight were selected by a backward elimination method to estimate the Srelative. The results showed that the Srelative index is strongly influenced by properties of the porous fraction, with total porosity and continuity of pores being of significant influence. Management with liquid bovine biofertilizer results in improvement in the soil structure, with effects measured by the Srelative index.

ABSTRACT The present study aimed at assessing the influence of physical properties associated with soil structure on the Srelative index. Two soil conditions under Ficus carica L. cultivation were studied (with or without liquid bovine biofertilizer in the irrigation water), in the 0-0.1 m and 0-0.3 m layers. Disturbed and undisturbed soil samples were collected from the above-mentioned layers and physical analyzes, pertinent to the study objective, were performed. The response function model was applied to verify how the soil independent physical variables influence on the Srelative index in the 0-0.1 m and 0-0.3 m layers, with 0 and 60% biofertilizer, being combined two to two. Once the response functions were known, the slopes of both functions were compared, being represented by the coefficients β11-β12 and β21-β22. This comparison enabled verifying whether there was an effect of the treatments on the response variable. In addition, the standard error of the difference between coefficients was calculated, and the Student's t-test applied. The method of multiple regression was also used to confirm the effect of the variables on the Srelative index for the 0-0.3 m layer in both treatments. Then, the variables with greater weight were selected by a backward elimination method to estimate the Srelative. The results showed that the Srelative index is strongly influenced by properties of the porous fraction, with total porosity and continuity of pores being of significant influence. Management with liquid bovine biofertilizer results in improvement in the soil structure, with effects measured by the Srelative index. | RESUMO Objetivou-se com esta pesquisa estudar a influência de atributos físicos associados à estrutura do solo no índice Srelativo. Foram contempladas duas situações de solo (sob cultivo de Ficus carica L., sem aplicação e com aplicação de biofertilizante bovino líquido na lâmina de irrigação), nas camadas de 0-0,1 m e 0-0,3 m. Foram coletadas amostras de solo com estrutura preservada e não preservada nas camadas supracitadas e realizadas análises físicas pertinentes ao objetivo do estudo. Foi aplicado o modelo de função de resposta para verificar como as variáveis físicas do solo independentes influenciam no Srelativo, nas camadas de 0-0,1 m e 0-0,3 m tratadas com 0 e 60 % do biofertilizante combinadas duas a duas. Conhecidas as funções de resposta compararam-se as inclinações de ambas as funções, representadas pelos coeficientes β11-β12 e β21-β22, para verificar se houve efeito dos tratamentos na variável resposta. Além disso, calculou-se o erro padrão da diferença entre os coeficientes e aplicou-se o teste t de Student. Também foi aplicado o método de regressão múltipla para verificar o efeito das variáveis sobre o Srelativo para a camada de 0-0,3 m em ambos os tratamentos. Em seguida, por meio do método backward elimination foram selecionadas as variáveis com maior peso para a estimativa do Srelativo. Concluiu-se que o índice Srelativo é fortemente influenciado por atributos da fração porosa, sendo a porosidade total e a continuidade de poros os de influência significativa. O manejo com biofertilizante bovino líquido resulta em melhora na estrutura do solo, com efeitos mensuráveis pelo índice Srelativo.

Some forages release allelopathic substances into the environment, and may prevent consortium with arboreal species in pastures. The objective of this work was to evaluate photosynthetic characteristics of pequizeiro plants (hereafter pequi) influenced by concentrations of residues of the forage species Urocholoa decumbens, Melinis minutiflora and Paspalum notatum. The treatments consisted of pequi cultivation under aerial residues of the three forage species mixed to the substrate in four concentrations (1, 2, 3 and 4% mass/mass), plus an additional treatment (comparative control) with pequi cultivated on the substrate without waste. The following parameters were evaluated: photosynthetic rate, stomatal conductance, transpiration rate, relationship between internal and external CO2 concentration (Ci/Ca), maximum quantum yield, effective quantum yield of FS II, electron transport rate, nonchemical quenching and chlorophyll index, concerning the content of chlorophyll a, b and total in pequi plants at 50 and 100 days after transplanting (DAT), and the relative production of dry matter at 100 DAT. At 50 DAT, the following photosynthetic variables were affected in pequi plants: A, gs, chlorophyll a, chlorophyll b and total chlorophyll when cultivated in the presence of forage residues. At 100 DAT, the following photosynthetic variables were affected in pequi plants: A, Fv/Fm, ETR, NPQ, chlorophyll a, chlorophyll b and total chlorophyll, when cultivated in the presence of forage residues. Pequi plants had reduced relative dry matter yield when grown in the presence of U. decumbens. This variable was also affected when pequi was grown in increasing concentrations of residues of the species U. decumbens, M. minutiflora and P. notatum.

ABSTRACT Some forages release allelopathic substances into the environment, and may prevent consortium with arboreal species in pastures. The objective of this work was to evaluate photosynthetic characteristics of pequizeiro plants (hereafter pequi) influenced by concentrations of residues of the forage species Urocholoa decumbens, Melinis minutiflora and Paspalum notatum. The treatments consisted of pequi cultivation under aerial residues of the three forage species mixed to the substrate in four concentrations (1, 2, 3 and 4% mass/mass), plus an additional treatment (comparative control) with pequi cultivated on the substrate without waste. The following parameters were evaluated: photosynthetic rate, stomatal conductance, transpiration rate, relationship between internal and external CO2 concentration (Ci/Ca), maximum quantum yield, effective quantum yield of FS II, electron transport rate, nonchemical quenching and chlorophyll index, concerning the content of chlorophyll a, b and total in pequi plants at 50 and 100 days after transplanting (DAT), and the relative production of dry matter at 100 DAT. At 50 DAT, the following photosynthetic variables were affected in pequi plants: A, gs, chlorophyll a, chlorophyll b and total chlorophyll when cultivated in the presence of forage residues. At 100 DAT, the following photosynthetic variables were affected in pequi plants: A, Fv/Fm, ETR, NPQ, chlorophyll a, chlorophyll b and total chlorophyll, when cultivated in the presence of forage residues. Pequi plants had reduced relative dry matter yield when grown in the presence of U. decumbens. This variable was also affected when pequi was grown in increasing concentrations of residues of the species U. decumbens, M. minutiflora and P. notatum. | RESUMO Algumas forrageias liberam no ambiente substancias alelopáticas, podendo inviabilizar o consórcio com espécies arbóreas em pastagens. O objetivo deste trabalho foi avaliar características fotossintéticas do pequizeiro influenciadas por concentrações de resíduos das espécies forrageiras Urocholoa decumbens, Melinis minutiflora e Paspalum notatum. Os tratamentos consistiram do cultivo de pequi sob resíduos da parte aérea das três espécies forrageiras misturadas ao substrato em quatro concentrações (1, 2, 3 e 4% massa/massa), mais um tratamento adicional (testemunha comparativa) com pequi cultivado no substrato sem resíduos. Foi avaliada a taxa fotossintética, condutância estomática, taxa transpiratória, relação entre a concentração interna e externa de CO2 (Ci/CA), rendimento quântico máximo, rendimento quântico efetivo do FS II, taxa de transporte de elétrons, quenching não fotoquímico e índice clorofilog referente ao conteúdo das clorofilas a, b e total em plantas de pequi aos 50 e 100 dias após o transplantio (DAT) e a produção relativa referente à matéria seca aos 100 DAT. Aos 50 DAT, as plantas de pequi foram afetadas quanto as variáveis fotossintéticas A, g s , clorofila a, clorofila b e clorofila total, quando cultivadas na presença de resíduos das forrageiras. Aos 100 DAT, as plantas de pequi foram afetadas quanto as variáveis fotossintéticas A, Fv/Fm, ETR, NPQ, clorofila a, clorofila b e clorofila total, quando cultivadas na presença de resíduos das forrageiras. O pequizeiro tem produção de matéria seca relativa reduzida quando cultivado na presença de resíduos da espécie U. decumbens. Essa variável também é afetada quando o pequi é cultivado em concentrações crescentes de resíduos das espécies U. decumbens, M. minutiflora e P. notatum.

Cassava is mostly planted in sandy soils which are usually of low fertility, thereby making it necessary to perform beneficial associations with microorganisms that can promote their growth. In this perspective, the possibility of selecting bacterial isolates efficient in promoting the growth of the culture is evident, which can provide subsidies for future inoculants. The objective of this study was to isolate, identify, select and evaluate the genetic diversity of endophytic bacteria in roots and stems of cassava grown in Garanhuns - PE, with features involved in promoting plant growth. The isolation was performed on culture medium semisolid LGI-P. The selected isolates were evaluated for the potential to fix N2, as the ability to produce indole acetic acid, for their ability to solubilize inorganic phosphate and produce exopolysaccharides. Some bacterial isolates had their 16S rRNA gene sequenced by the Sanger method. A total of 52 endophytic bacteria isolates were obtained from cassava. Regarding the potential to fix N2, 15% of the isolates were positive. As for the production of IAA, 78% of the isolates produced this phytohormone in a medium with increased L-tryptophan. Approximately 31% of the isolates were able to solubilize inorganic phosphate and 60% had exopolysaccharide. The identification of 19 isolates allowed the grouping into six bacterial genera, namely: Achromobacter, Bacillus, Burkholderia, Enterobacter, Pantoea and Pseudomonas. Cassava plants grown in Garanhuns - PE present interaction with different groups of endophytic bacteria and there are bacterial groups with several characteristics involved in promoting plant growth.

RESUMO A mandioca é, geralmente, plantada em solos arenosos e de baixa fertilidade, tornando eminente a necessidade da mesma em realizar associações benéficas com micro-organismos que possam auxiliar seu crescimento. Nessa ótica, é evidente a possibilidade de seleção de isolados bacterianos eficientes em promover o crescimento da cultura, os quais podem fornecer subsídios para futuros inoculantes. O objetivo deste trabalho foi isolar, identificar, selecionar e avaliar a diversidade genética de bactérias endofíticas de raízes e caules de mandioca, cultivada em Garanhuns - PE, com características envolvidas na promoção de crescimento vegetal. O isolamento foi realizado em meio de cultura semissólido LGI-P. Os isolados selecionados foram avaliados quanto ao potencial de fixar N2, quanto à capacidade de produzir ácido indol acético, quanto à capacidade de solubilizar fosfato inorgânico e produzir exopolissacarídeos. Alguns isolados bacterianos tiveram o gene 16S rRNA sequenciados pelo método de Sanger. No total, foram obtidos 52 isolados de bactérias endofíticas de mandioca. Em relação ao potencial para fixar N2, 15% dos isolados foram positivos. Quanto à produção de AIA, 78% dos isolados produziram este fitohormônio em meio com o acréscimo de L-triptofano. Cerca de 31% dos isolados foram capazes de solubilizar fosfato inorgânico e 60% apresentaram produção de exopolissacarídeos. A identificação de 19 isolados possibilitou o agrupamento em seis gêneros bacterianos, sendo eles: Achromobacter, Bacillus, Burkholderia, Enterobacter, Pantoea e Pseudomonas. Plantas de mandioca cultivadas em Garanhuns - PE apresentam interação com diferentes grupos de bactérias endofíticas e há grupos bacterianos com diversas características envolvidas na promoção de crescimento vegetal. | ABSTRACT Cassava is mostly planted in sandy soils which are usually of low fertility, thereby making it necessary to perform beneficial associations with microorganisms that can promote their growth. In this perspective, the possibility of selecting bacterial isolates efficient in promoting the growth of the culture is evident, which can provide subsidies for future inoculants. The objective of this study was to isolate, identify, select and evaluate the genetic diversity of endophytic bacteria in roots and stems of cassava grown in Garanhuns - PE, with features involved in promoting plant growth. The isolation was performed on culture medium semisolid LGI-P. The selected isolates were evaluated for the potential to fix N2, as the ability to produce indole acetic acid, for their ability to solubilize inorganic phosphate and produce exopolysaccharides. Some bacterial isolates had their 16S rRNA gene sequenced by the Sanger method. A total of 52 endophytic bacteria isolates were obtained from cassava. Regarding the potential to fix N2, 15% of the isolates were positive. As for the production of IAA, 78% of the isolates produced this phytohormone in a medium with increased L-tryptophan. Approximately 31% of the isolates were able to solubilize inorganic phosphate and 60% had exopolysaccharide. The identification of 19 isolates allowed the grouping into six bacterial genera, namely: Achromobacter, Bacillus, Burkholderia, Enterobacter, Pantoea and Pseudomonas. Cassava plants grown in Garanhuns - PE present interaction with different groups of endophytic bacteria and there are bacterial groups with several characteristics involved in promoting plant growth.

Spatial arrangement and population density of component cultures, when well structured, may contribute to increased crop yields relative to monocultures. Thus, the objective of this work was to evaluate the productive performance of carrot and cowpea in an intercropping system under different spatial arrangements and population densities. This research was conducted on the “Rafael Fernandes” experimental farm of the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN, Brazil. The experimental design was a randomized complete block with four replicates, where the treatments were arranged in a 3 × 4 factorial scheme, in which the first factor was three spatial arrangements (2:2, 3:3, and 4:4) and the second factor was four different population densities of cowpea (100%, 80%, 60%, and 40% of the recommended population in the single crop RPSC). Rooster tree Calotropis procera (Ait.) R.Br., a spontaneous species of the „Caatinga‟ biome, was used as fertilizer. The characteristics evaluated in carrot were as follows: total and commercial productivity of roots and classified root production. The following characteristics were evaluated for cowpea: number of pods per square meter, length and yield of green pods, number of grains per pod, 100grain weight, and yield of green grains. The modified monetary advantage was used to evaluate the feasibility of the intercropped systems. Spatial arrangements between the component cultures did not influence the agroeconomic performance of the carrot-cowpea intercropping system. The highest agro-economic performance of the carrot-cowpea intercropping was obtained in the population of cowpea, which was 42% of the RPSC.

RESUMO O arranjo espacial e a densidade populacional das culturas componentes quando bem estruturados podem contribuir para aumentar os rendimentos das culturas em relação ao monocultivos. Assim, o objetivo deste trabalho foi avaliar o desempenho produtivo da cenoura e do feijão-caupi em sistema consorciado sob diferentes arranjos espaciais e densidades populacionais. Essa pessquisa foi conduzida na fazenda experimental "Rafael Fernandes" da Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN, Brasil. O delineamento experimental foi de blocos completos casualizados com quatro repetições, em esquema fatorial 3 x 4 em que o primeiro fator foi três arranjos espaciais (2: 2, 3:3 e 4:4) e o segundo fator quatro densidades populacionais de feijão-caupi (100, 80, 60 e 40% da população recomendada no cultivo solteiro - PRCS). O experimento foi adubado com flor-de-seda (Calotropis procera (Ait.) R.Br.), uma espécie espontânea do bioma Caatinga. As características avaliadas na cenoura foram: produtividade total e comercial de raízes e produtividade classificada de raízes. Para o feijão-caupi foi avaliado as seguintes características: número de vagens por metro quadrado, comprimento e produtividade de vagens verdes, número de grãos por vagem, peso de 100 grãos e produtividade de grãos verdes. A vantagem monetária corrigida foi utilizada para avaliar a viabilidade dos sistemas consorciados. Não se observou influencia dos arranjos espaciais entre as culturas componentes no desempenho agroeconômico do consórcio de cenoura x feijão-caupi. A mais alta performance agroeconômica do consórcio cenoura x feijão-caupi foi obtida na densidade populacional de caupi de 42% da PRCS. | ABSTRACT Spatial arrangement and population density of component cultures, when well structured, may contribute to increased crop yields relative to monocultures. Thus, the objective of this work was to evaluate the productive performance of carrot and cowpea in an intercropping system under different spatial arrangements and population densities. This research was conducted on the “Rafael Fernandes” experimental farm of the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN, Brazil. The experimental design was a randomized complete block with four replicates, where the treatments were arranged in a 3 × 4 factorial scheme, in which the first factor was three spatial arrangements (2:2, 3:3, and 4:4) and the second factor was four different population densities of cowpea (100%, 80%, 60%, and 40% of the recommended population in the single crop [RPSC]). Rooster tree Calotropis procera (Ait.) R.Br., a spontaneous species of the „Caatinga‟ biome, was used as fertilizer. The characteristics evaluated in carrot were as follows: total and commercial productivity of roots and classified root production. The following characteristics were evaluated for cowpea: number of pods per square meter, length and yield of green pods, number of grains per pod, 100grain weight, and yield of green grains. The modified monetary advantage was used to evaluate the feasibility of the intercropped systems. Spatial arrangements between the component cultures did not influence the agroeconomic performance of the carrot-cowpea intercropping system. The highest agro-economic performance of the carrot-cowpea intercropping was obtained in the population of cowpea, which was 42% of the RPSC.

Common beans (Phaseolus vulgaris L.) are one of the most important protein sources worldwide. However, infestation by bruchids compromises the storage of these beans after harvest. The objective of this study was to determine the emergence rate of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in four P. vulgaris varieties (Carioca Pitoco, Enxofre, Gorgutuba Vermelho, and Rosinha) cultivated in the southwestern Amazon (State of Acre, Brazil). The grains from each variety were infested with 50 non-sexed adult Z. subfasciatus, and the insects were collected 13 days after initiating the bioassays. The adult progeny was collected from each plant variety on alternate days from the beginning to the end of the emergence period, and they were counted (number of insects/jar). The sum of emerged insects per day (SEd) was determined from the beginning of the emergence period, from which the accumulated emergence was calculated (SEa= ΣSEd, % day). There were differences in the emergence rates of Z. subfasciatus among the bean varieties, with the rates being lower in the Gorgutuba Vermelho variety. Although this bean variety had the lowest peak of adult insect emergence, the period of insect development was not of increased length in this variety compared to the other varieties. In general, the Gorgutuba Vermelho variety appears to be resistant to Z. subfasciatus.

RESUMO O feijão comum (Phaseolus vulgaris L.) é uma das fontes proteicas mais importantes em todo o mundo. Todavia, o ataque de bruquídeos inviabiliza o armazenamento do produto após a colheita. O objetivo deste trabalho foi determinar a taxa de emergência de Zabrotes subfasciatus (Coleoptera: Chrysomelidae) em quatro variedades de feijão P. vulgaris (Carioca Pitoco, Enxofre, Gorgutuba Vermelho e Rosinha) cultivadas na Amazônia sul-ocidental (Acre, Brasil). Os grãos de cada variedade foram infestados com 50 adultos não-sexados e após 13 dias do início dos bioensaios, os insetos foram removidos. A progênie adulta obtida nas variedades foi contabilizada e removida em dias alternados, a partir da primeira emergência, até o final do período de emergência (n° de insetos/frasco). A soma da emergência de insetos foi acumulada a partir da emergência inicial e resultou na soma da emergência acumulada (SEa, % dia), calculada por SEa = ∑SEd. Foram constadas diferenças nas taxas de emergência de Z. subfasciatus entre as variedades de feijão, sendo que a variedade Gorgutuba Vermelho apresentou menor taxa de emergência. Embora esta variedade de feijão tenha apresentado menor emergência de adultos, o tempo de desenvolvimento dos insetos não se estendeu nesta variedade, em comparação com as outras variedades. Em geral, a variedade Gorgutuba Vermelho apresentou indícios de fontes resistência a Z. subfasciatus. | ABSTRACT Common beans (Phaseolus vulgaris L.) are one of the most important protein sources worldwide. However, infestation by bruchids compromises the storage of these beans after harvest. The objective of this study was to determine the emergence rate of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in four P. vulgaris varieties (Carioca Pitoco, Enxofre, Gorgutuba Vermelho, and Rosinha) cultivated in the southwestern Amazon (State of Acre, Brazil). The grains from each variety were infested with 50 non-sexed adult Z. subfasciatus, and the insects were collected 13 days after initiating the bioassays. The adult progeny was collected from each plant variety on alternate days from the beginning to the end of the emergence period, and they were counted (number of insects/jar). The sum of emerged insects per day (SEd) was determined from the beginning of the emergence period, from which the accumulated emergence was calculated (SEa= ΣSEd, % day). There were differences in the emergence rates of Z. subfasciatus among the bean varieties, with the rates being lower in the Gorgutuba Vermelho variety. Although this bean variety had the lowest peak of adult insect emergence, the period of insect development was not of increased length in this variety compared to the other varieties. In general, the Gorgutuba Vermelho variety appears to be resistant to Z. subfasciatus.

Carnauba (Copernicia prunifera) is a forest species with multiple uses, and is of great economic and social importance for several communities involved in extractive agriculture in northeastern Brazil. However, there are few studies on genetic variability in this species. Thus, this work aimed to produce information about the genetic characterization of C. prunifera seeds and seedlings, using provenance and progeny evaluations. A progeny test was performed in a plant nursery, using seeds of 36 matrices sampled in the municipalities of Mossoró and Apodi (Rio Grande do Norte State), and Russas and Icapuí (Ceará State). Three groups were derived according to the spatial distance between the collected matrices. Biometric analyses of the seeds were performed, adopting a completely randomized experimental design, with four replicates of 25 seeds in each analysis. A randomized block design (five replicates and five plants per plot) was used at the seedling production phase. The data evaluated included the emergence speed index, emergence percentage, leaf size, leaf base diameter, and survival (at 30, 60, and 90 days after sowing). The restricted maximum likelihood method was used in the statistical analysis, with the aid of SELEGEN software. In order to evaluate genetic variability in the C. prunifera population samples, it was verified that the juvenile characters presented a moderate genetic control. The three groups of spatially delimited matrices presented no significant genetic differences. This information may assist in the development of forestry practice for this species.

ABSTRACT Carnauba (Copernicia prunifera) is a forest species with multiple uses, and is of great economic and social importance for several communities involved in extractive agriculture in northeastern Brazil. However, there are few studies on genetic variability in this species. Thus, this work aimed to produce information about the genetic characterization of C. prunifera seeds and seedlings, using provenance and progeny evaluations. A progeny test was performed in a plant nursery, using seeds of 36 matrices sampled in the municipalities of Mossoró and Apodi (Rio Grande do Norte State), and Russas and Icapuí (Ceará State). Three groups were derived according to the spatial distance between the collected matrices. Biometric analyses of the seeds were performed, adopting a completely randomized experimental design, with four replicates of 25 seeds in each analysis. A randomized block design (five replicates and five plants per plot) was used at the seedling production phase. The data evaluated included the emergence speed index, emergence percentage, leaf size, leaf base diameter, and survival (at 30, 60, and 90 days after sowing). The restricted maximum likelihood method was used in the statistical analysis, with the aid of SELEGEN software. In order to evaluate genetic variability in the C. prunifera population samples, it was verified that the juvenile characters presented a moderate genetic control. The three groups of spatially delimited matrices presented no significant genetic differences. This information may assist in the development of forestry practice for this species. | RESUMO A carnaubeira (Copernicia prunifera) é uma espécie florestal que apresenta múltiplos usos e de grande importância econômica e social para várias famílias extrativistas no Nordeste brasileiro. Entretanto, são escassos os estudos a respeito da variabilidade genética da espécie. Assim, este trabalho buscou gerar informações em relação à caracterização genética de sementes e mudas de Copernicia prunifera, avaliando procedências e progênies. Instalou-se um teste de progênies, em viveiro, a partir de sementes de 36 matrizes amostradas nos Municípios de Mossoró e Apodi, no Estado do Rio Grande do Norte; e em Russas e Icapuí, no Estado do Ceará. A partir da distância espacial entre as matrizes coletadas foram formados três grupos. Foram realizadas análises biométricas das sementes, adotando o delineamento experimental inteiramente casualizado, com quatro repetições de 25 sementes para cada análise. O delineamento em blocos casualizados com cinco repetições e cinco plantas por parcela foi empregado na fase de produção de mudas. Os dados avaliados incluíram: índice de velocidade de emergência, porcentagem de emergência, tamanho da folha, diâmetro da base da folha e sobrevivência (aos 30, 60 e 90 dias após a semeadura). A metodologia de máxima verossimilhança restrita foi utilizada para a análise estatística, com o auxílio do software SELEGEN. Verificou-se que os caracteres juvenis apresentam controle genético médio, podendo ser utilizados para avaliação da variabilidade genética de amostras de populações da espécie. Os três grupos de matrizes delimitados espacialmente não apresentam diferenças genéticas significativas. Essas informações podem auxiliar no desenvolvimento da silvicultura da espécie.

Irrigation with saline water is a worldwide necessity an excess of salts in water or in soil causes growth inhibition, and negatively affects the productivity of many crops. Application of nitrogen fertilizers may be a way of mitigating the effects of salts on plants. The aim of this study was to evaluate the accumulation of biomass and the chlorophyll pigment content in jackfruit seedlings irrigated with water of increasing salinity level in soil with nitrogen sources. The treatments were distributed in randomized blocks with four replicates and three plants per plot, arranged in a 5 × 3 factorial scheme, related to electrical conductivity levels of the irrigation water of 0.3, 1.0, 2.0, 3.0 and 4.0 dS m-1, in soil without nitrogen, with ammonium sulfate and with urea, in a split application 60 and 75 days after sowing. An increase in the salinity of the water increased the salinity levels of soil, which was intensified by a dose of 150 mg of N, mainly when applied in the form of ammonium sulfate, inhibiting dry matter production and chlorophyll content in jackfruit seedlings. The greatest reductions in chlorophyll a and b content occurred in jackfruit seedlings irrigated with water of 4.0 dS m-1 conductivity in the soil without nitrogen fertilization. Urea is the most suitable nitrogen source for the production of seedlings under conditions of high salinity.

RESUMO A irrigação com água salina é uma necessidade mundial e o excesso de sais da água ou do solo, causa inibição no crescimento e no rendimento da grande maioria das plantas cultivadas. Nesse contexto, os fertilizantes nitrogenados podem constituir alternativa para a mitigação dos efeitos dos sais sobre as plantas. Com isso, objetivou-se avaliar o acúmulo de biomassa e o índice de pigmentos clorofiláticos em mudas de jaqueira irrigadas com água de salinidades crescentes no solo com fontes de nitrogênio. Os tratamentos foram distribuídos em blocos casualizados com quatro repetições e com três plantas por parcela, arranjados em fatorial 5 × 3, relativo aos níveis de condutividade elétrica da água de irrigação de 0,3; 1,0; 2,0; 3,0 e 4,0 dS m-1, no solo sem nitrogênio, com sulfato de amônio e com ureia aplicados parceladamente aos 60 e 75 dias após a semeadura. O aumento da salinidade da água elevou a salinidade do solo, a qual foi intensificada pela dose de 150 mg de N, principalmente quando aplicada na forma de sulfato de amônio, ao ponto de inibir a formação de massa da matéria seca e os teores de clorofila em mudas de jaqueira. As maiores reduções no índice de clorofila a e b foram nas mudas de jaqueira irrigadas com água de 4,0 dS m-1 no solo sem adubação nitrogenada. A ureia é a fonte nitrogenada mais indicada para produção de mudas em condições de elevada salinidade. | ABSTRACT Irrigation with saline water is a worldwide necessity an excess of salts in water or in soil causes growth inhibition, and negatively affects the productivity of many crops. Application of nitrogen fertilizers may be a way of mitigating the effects of salts on plants. The aim of this study was to evaluate the accumulation of biomass and the chlorophyll pigment content in jackfruit seedlings irrigated with water of increasing salinity level in soil with nitrogen sources. The treatments were distributed in randomized blocks with four replicates and three plants per plot, arranged in a 5 × 3 factorial scheme, related to electrical conductivity levels of the irrigation water of 0.3, 1.0, 2.0, 3.0 and 4.0 dS m-1, in soil without nitrogen, with ammonium sulfate and with urea, in a split application 60 and 75 days after sowing. An increase in the salinity of the water increased the salinity levels of soil, which was intensified by a dose of 150 mg of N, mainly when applied in the form of ammonium sulfate, inhibiting dry matter production and chlorophyll content in jackfruit seedlings. The greatest reductions in chlorophyll a and b content occurred in jackfruit seedlings irrigated with water of 4.0 dS m-1 conductivity in the soil without nitrogen fertilization. Urea is the most suitable nitrogen source for the production of seedlings under conditions of high salinity.

Vetiver grass is a member of the grass family Poaceae. Its fast development is probably due to the interaction with native microbiota, whose influence has not been studied yet. The objective of this work was to evaluate the colonization and development of the vetiver grass (Chrysopogon zizanioides (L.) Roberty) inoculated with arbuscular mycorrhizal fungi and dark septate endophytic fungi. The experimental design was a completely randomized design with six treatments (control, without mycorrhizal fungi, native inoculants, UFLA05 - Gigaspora albida, UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum, and UFLA401 - Acaulospora morrowiae), with three replicates each. Vetiver grass tillers as well as the native microbial inoculum were obtained from the Lower São Francisco river experimental area, located in Sergipe state, Northeastern Brazil. There was a negative interaction between all tested UFLAs mycorrhizal isolates and the native microbiota (mycorrhizal and endophytic fungi) in the treatments, especially when taking into consideration plant height and volume of roots. The effects of inoculation with UFLA isolates may have been influenced by the presence of the native mycorrhizal fungi and the dark septate endophytic fungi. Vetiver grass was responsive to the native inoculant. The mycorrhizal colonization of the vetiver grass was vesicular, but the formation of the arbuscules can be influenced by the interaction between the fungus, plant, and the environment.

ABSTRACT Vetiver grass is a member of the grass family Poaceae. Its fast development is probably due to the interaction with native microbiota, whose influence has not been studied yet. The objective of this work was to evaluate the colonization and development of the vetiver grass (Chrysopogon zizanioides (L.) Roberty) inoculated with arbuscular mycorrhizal fungi and dark septate endophytic fungi. The experimental design was a completely randomized design with six treatments (control, without mycorrhizal fungi, native inoculants, UFLA05 - Gigaspora albida, UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum, and UFLA401 - Acaulospora morrowiae), with three replicates each. Vetiver grass tillers as well as the native microbial inoculum were obtained from the Lower São Francisco river experimental area, located in Sergipe state, Northeastern Brazil. There was a negative interaction between all tested UFLAs mycorrhizal isolates and the native microbiota (mycorrhizal and endophytic fungi) in the treatments, especially when taking into consideration plant height and volume of roots. The effects of inoculation with UFLA isolates may have been influenced by the presence of the native mycorrhizal fungi and the dark septate endophytic fungi. Vetiver grass was responsive to the native inoculant. The mycorrhizal colonization of the vetiver grass was vesicular, but the formation of the arbuscules can be influenced by the interaction between the fungus, plant, and the environment. | RESUMO O capim vetiver é uma espécie da família poácea que apresenta rápido desenvolvimento, provavelmente decorrente da interação com a microbiota nativa, cuja influência ainda não foi estudada. O objetivo deste trabalho foi avaliar a colonização e o desenvolvimento do capim vetiver inoculado com fungos micorrízicos arbusculares e fungos endofíticos "dark septate". O delineamento experimental utilizado foi inteiramente casualizado composto por seis tratamentos (controle sem fungo micorrízico; inoculante microbiano nativo; UFLA05 - Gigaspora albida, UFLA351 - Rhizoglomus clarum, UFLA372 - Claroideoglomus etunicatum e UFLA401 - Acaulospora morrowiae), com três repetições. Os perfilhos de capim vetiver, assim como o inóculo microbiano nativo foram obtidos na área experimental do Baixo São Francisco, localizado no Estado de Sergipe, Nordeste do Brasil. O efeito da inoculação dos isolados UFLAs pode ter sido influenciado pela presença da micorriza nativa e pelos fungos endofíticos "dark septate". Houve uma interação negativa entre todos isolados UFLAs testados e a microbiota nativa (micorriza e endofítico), nos tratamentos, principalmente quando se considera a altura da planta e o volume de raízes. O capim vetiver foi responsivo ao inoculante microbiano nativo. A colonização micorrízica do capim vetiver foi vesicular, mas a formação dos arbúsculos pode ser influenciada pela interação fungo, planta e ambiente.

The use of stimulants in the establishment of arbuscular mycorrhizal fungi has great potential in contributing to P uptake by plants. This study aimed to evaluate the effect of isoflavonoid formononetin as mycorrhization stimulant on soybean associated with phosphate fertilizer in Oxisols with intermediate (OPi) and low (OPl) phosphorus availability, in the Cerrado region of Piauí. The experiment in each soil consisted of randomized blocks design in a 4×4 factorial scheme, with four replications. The treatments comprised of four phosphorus doses (0, 26.66, 40 and 80 kg ha-1 P2O5), and four isoflavonoid formononetin doses (0, 0.5, 0.9 and 1.8 g kg-1 soybean seeds). The variables evaluated were soybean growth, yield, nodulation and mycorrhizal colonization rate. With the exception of mycorrhizal colonization rate in OPi, plant height and number of pods per plant in OPl, the other variables were not affected by the application of isoflavonoid formononetin, in both soils. Yield linearly increased with increase in the phosphorus doses in OPl, and presented agronomic efficiency of ~15 kg ha-1 grain for each kg ha-1 P2O5 applied to the soil.

RESUMO O uso de estimulantes para o estabelecimento de fungos micorrízicos arbusculares tem grande potencial em contribuir para a absorção de P pelas plantas. Objetivou-se avaliar a eficácia do isoflavonóide formononetina como estimulante da micorrização na cultura da soja, associada a adubação fosfatada, em dois Latossolos com teores de fósforo disponível médio (LPm) e baixo (LPb) no Cerrado piauiense. O delineamento experimental em cada solo foi em blocos casualizados no esquema fatorial 4×4, com quatro repetições. Os tratamentos foram constituídos por quatro doses de fósforo (0; 26,66; 40 e 80 kg ha-1 de P2O5) e quatro doses do isoflavonóide formononetina (0; 0,5; 0,9 e 1,8 g kg-1 de semente de soja). As variáveis avaliadas foram, o crescimento, a produção, a nodulação e taxa de colonização micorrízica da soja. Com exceção da taxa de colonização micorrízica no LPm, altura e número de vagens por planta de soja no LPb, as demais variáveis, não foram influenciados pela aplicação do isoflavonóide formononetina, em ambos os solos. A produtividade cresceu linearmente ao incremento das doses de fósforo no LPb, apresentando uma eficiência agronômica de ~15 kg ha-1 de grãos para cada kg ha-1 de P2O5 aplicado no solo. | ABSTRACT The use of stimulants in the establishment of arbuscular mycorrhizal fungi has great potential in contributing to P uptake by plants. This study aimed to evaluate the effect of isoflavonoid formononetin as mycorrhization stimulant on soybean associated with phosphate fertilizer in Oxisols with intermediate (OPi) and low (OPl) phosphorus availability, in the Cerrado region of Piauí. The experiment in each soil consisted of randomized blocks design in a 4×4 factorial scheme, with four replications. The treatments comprised of four phosphorus doses (0, 26.66, 40 and 80 kg ha-1 P2O5), and four isoflavonoid formononetin doses (0, 0.5, 0.9 and 1.8 g kg-1 soybean seeds). The variables evaluated were soybean growth, yield, nodulation and mycorrhizal colonization rate. With the exception of mycorrhizal colonization rate in OPi, plant height and number of pods per plant in OPl, the other variables were not affected by the application of isoflavonoid formononetin, in both soils. Yield linearly increased with increase in the phosphorus doses in OPl, and presented agronomic efficiency of ~15 kg ha-1 grain for each kg ha-1 P2O5 applied to the soil.