Molecular characterization and transcriptional analysis of VrWOX genes in mungbean Vigna radiate (L.) Wilczek / 生物工程学报

WUSCHEL-related homebox (WOX) gene family is a type of plant specific transcription factor, and belongs to the homeobox (HB) transcription factor superfamily. WOX genes play an important role in plant development, such as stem cell regulation and reproductive progress, and have been identified in many plant species. However, the information of mungbean VrWOX genes is limited. In this study, we identified 42 VrWOX genes in mungbean genome using Arabidopsis AtWOX genes as BLAST queries. VrWOX genes are unevenly distributed on 11 mungbean chromosomes, and chromosome 7 contains the most VrWOX genes. VrWOX genes are classified into three subgroups, the ancient group, the intermediate group and the modern/WUSCHEL group, which contains 19, 12 and 11 VrWOX members, respectively. Intraspecific synteny analysis revealed 12 VrWOX duplicated gene pairs in mungbean. Mungbean and Arabidopsis thaliana have 15 orthologous genes, and mungbean and Phaseolus vulgaris have 22 orthologous genes, respectively. The gene structure and conserved motif are different among VrWOX genes, indicating their functional diversity. The promoter regions of VrWOX genes contain different number and type of cis-acting elements, and VrWOX genes show distinct expression levels in eight mungbean tissues. Our study investigated the bioinformation and expression profiles of VrWOX genes, and provided essential information for further functional characterization of VrWOX genes.

Silicon as resistance inducer to control black apphid Aphis craccivora Koch, 1854 in cowpea beans [Vigna unguiculata (L)] Walp

The black aphid Aphis craccivora (Koch, 1854) stands out between the bugs considered cowpea pests. The objective of this study was to evaluate the effects of silicon application on the resistance induction of cowpea plants to the black aphid A. craccivora. The experiment was conducted in the Entomology Laboratory of the Phytosanitary sector of the Centro de Ciências Agrárias at the Universidade Federal do Piauí. The effects of the application of silicon on biological aspects were evaluated using a completely randomized design, with four treatments and 40 repetitions, being: silicon in soil (T1), silicon in soil + leaf (T2), silicone leaf (T3), and control (T4). The following biological variables were evaluated: generation period, reproductive period, fecundity, and daily average of nymphs per female. The silicon and lignin contents were also evaluated in the plants. The silicic acid was applied in a 1% solution around the stem of the plants (soil), 15 days after emergence, by diluting 2 g of the product in 200 mL of water. However, the leaf application was carried out with sprayer five days after application in soil. The non-preference of A. craccivora on bean was also evaluated. The evaluations were performed after 24, 48 and 72 hours of infestation by counting nymphs at 24, 48 and 72 hours and adults at each leaf session. The application of silicon promotes the reduction of the production of nymphs, interfering in the biological aspects of A. craccivora, and has potential to be used in a cowpea pest management program in cowpea.

The Bradyrhizobium uaiense strain UFLA 03-164T enhanced yield performance of cowpea in soils with low or high phosphorus content

The objective of this study was to evaluate the agronomic efficiency of rhizobia strains already approved or in the selection stage for cowpea, in the Recôncavo da Bahia region, Brazil. Two field experiments were performed in the municipalities of Cruz das Almas and Maragogipe, Bahia, Brazil. A randomized block design was used with seven nitrogen sources and four replicates. Nitrogen sources consisted of the strains UFRB FA51B1, UFRB BA72C2-1, UFLA 03-164T, UFLA 03-84, INPA 03-11B, and two controls without inoculation, one with mineral nitrogen and another without. All the strains nodulated cowpea. The efficiency of the strains was determined by the number of nodules, nodule dry matter, total dry matter, grain yield, nitrogen accumulation in shoots and grain, and relative efficiency. The strain UFLA 03-164T can be recommended for biomass production, green manure, and promotion of grain yields in both soils. In Maragogipe, the UFLA 03-84 and INPA 03-11B strains can be recommended for biomass production, green manure, and promotion of grain yields. The UFLA 03-164T strain showed great potential to promote and grain yield in the two municipalities studied. The strain INPA 03-11B can be recommended for Maragogipe soil. UFLA 03-84 can also be recommended to increase grain yield in Cruz das Almas.

Effect of cowpea (Vigna unguiculata L. Walp) sowing season on population dynamics of pest insects

Several factors limit cowpea quality and yield, such as the choice of a cultivar better adapted to the region, the ideal sowing season, as well as diseases and pests. Aimed to evaluate the effect of different sowing seasons on the population dynamics of pest insects of cowpea crops. The study was carried out during the dry season, the rainy season, and the season recommended for sowing by the Experimental Farm of the Federal University of Amazonas (FAEXP­UFAM), Brazil. A total of 33 weekly collections were carried out during the three sowing seasons, distributed in two ways according to the phenological stage of the crop: manual collection per linear meter of plantation and entomological scanning net. The faunistic analysis detected the pest insects Acromyrmex laticeps nigrosetosus, Cerotoma arcuata, Crinocerus sanctus, Euschistus heros, Horciasinus signoreti, Liriomyza sativae, and Nezara viridula. Of these species, H. signoreti stands out for being recorded for the first time as predominant in cowpea crops in the Brazilian state of Amazonas. Infections by hemipterans such as C. sanctus, E. heros, H. signoreti, and N. viridula were detected throughout the study, regardless of the sowing season, except for H. signoreti, which was dominant in all three seasons. The highest infestation of C. arcuata occurred during the recommended sowing season for cowpeas (June to August). According to the Jaccard index, plantation I e II share 86% of the species. This study provides important information to programs in insect control and management and to the agronomic decision-making process.

Productivity and growth in cowpea inoculated with rhizobia under different light environments

The objective of this work was to verify the influence of light environments combined with rhizobia inoculation on cowpea growth and productivity. A completely random design was used in a 4x4 factorial scheme, with four light environments, four nitrogen sources and eight replicates in split plot parcels. Light environments were set by means of photo-conversion and thermo-conversion nettings (Aluminet®, red net and black net) and control treatment without shading (full sun). Nitrogen sources were constituted by the strains INPA 03-11B - SEMIA 6462 (Bradyrhizobium elkanni) and UFLA 03-84 - SEMIA 6461 (Bradyrhizobium viridifuturi), and two control treatments: with 70 kg ha-1 of mineral nitrogen and without N. Plant height, indices of chlorophyll a, b and total chlorophill, the number of leaves, number of nodules, dry matter of nodules, dry matter of the aerial portion, dry matter of roots and total dry matter, relative efficiency, gathering of nitrogen in the aerial portion, number, length and matter of pods per plant and dry matter of 100 grains, were evaluated. . There was interaction between light conditions and nitrogen sources for the number of nodules. Individual effect was observed in all other variables. Strain INPA 03-11B was able to promote higher nodulation in cowpea plants in light environments under full sun and Aluminet and the strain UFLA 03-84 only under full sun conditions. However, the efficiency of diazotrophic bacteria to promote vegetative growth, nitrogen gathering and production was not influenced by different light environments. Thus, full sun cultivation is recommended, independently of the nitrogen source used.

Effects of exogenous γ-Aminobutyric acid on the regulation of respiration and protein expression in germinating seeds of mungbean (Vigna radiata) under salt conditions

BACKGROUND: γ-Aminobutyric acid (GABA) bypasses the TCA cycle via GABA shunt, suggesting a relationship with respiration. However, little is known about its role in seed germination under salt conditions. RESULTS: In this study, exogenous GABA was shown to have almost no influence on mungbean seed germination, except 0.1 mM at 10 h, while it completely alleviated the inhibition of germination by salt treatment. Seed respiration was significantly inhibited by 0.1 and 0.5 mM GABA, but was evidently enhanced under salt treatment, whereas both were promoted by 1 mM GABA alone or with salt treatment. Mitochondrial respiration also showed a similar trend at 0.1 mM GABA. Moreover, proteomic analysis further showed that 43 annotated proteins were affected by exogenous GABA, even 0.1 mM under salt treatment, including complexes of the mitochondrial respiratory chain. CONCLUSIONS: Our study provides new evidence that GABA may act as a signal molecule in regulating respiration of mungbean seed germination in response to salt stress.

Herbicide weed control ­ induced differential tolerance and productivity in cowpea plants / Controle de ervas daninhas com herbicida - tolerância diferencial induzida e produtividade em plantas de feijão-caupi

The use of herbicides is a represents an efficient way to control the infesting plant population, since it is associated with low operational cost, and it does not demand large amounts of labour. An obstacle to growing cowpea (Vigna unguiculate) is the absence of herbicides registered for this crop. The objective of this work was to evaluate the tolerance of cowpea to herbicides. The experiment was carried out in a randomised block with treatment controls with and without weeding, Bentazon (720 g ha-1), Fluazifop-p-butyl (250 g ha-1), Fomesafen and a tank mix between Fluazifop-p-butyl + Fomesafen (250 + 187.5 g ha-1) with treatment replicates. The herbicides were applied on vegetative (V3 ­ stage) cowpea plants using a CO2-pressurised backpack sprayer with four spray tips TT 110.02 operating at a pressure of 2.5 bar and applying 240 litres of syrup per hectare. The cultivar BRS Guariba, with five planting lines per plot, was tested with the three central lines of the useful area, scoring 0.5 m of the ends. The species Oxalis latifolia was difficult to control. The Fluazifop-p-butyl + Fomesafen mixture presented better control of weeds. The herbicides caused phytotoxicity to cowpea and reduced leaf area and dry mass. The productivity of the crop was affected due to the low control of weeds. It was concluded that the cowpea presented differential tolerance to the herbicides tested doses.

O uso de herbicidas é uma alternativa promissora, pois permite um controle eficiente da população de plantas infestantes, associado a baixo custo operacional e sem exigir grandes quantidades de mão de obra. No entanto, um entrave no controle de plantas daninhas no feijão-caupi é a ausência de herbicidas registrados para essa cultura. Objetivou-se com este trabalho avaliar a tolerância do feijão-caupi cultivar BRS Guariba, a herbicidas. Um ensaio foi conduzido a campo em blocos casualizados composto dos tratamentos, testemunhas com e sem capina, Bentazon (720 g i.a. ha-1), Fluazifop-p-butyl (250 g i.a. ha-1), Fomesafen (187,5 g i.a. ha-1) e mistura de tanque entre Fluazifop-p-butyl + Fomesafen (250 + 187,5 g i.a. ha-1) com 4 repetições. Os herbicidas foram aplicados com plantas de caupi em estágio vegetativo V3 com pulverizador costal pressurizado por CO2 com quatro pontas de pulverização TT 110.02 operando a uma pressão de 2,5 Bar e aplicando 240 L ha-1 de calda. As parcelas foram compostas 5 linhas de plantio com cinco metros de comprimento, espaçadas de 0,5 m, com as 3 linhas centrais de área útil, desprezando 0,5 m das extremidades. Avaliou-se a comunidade infestante, a eficiência de controle de plantas daninhas, a tolerância e a produtividade do feijão-caupi. A espécie Oxalis latifolia foi encontrada em todos os tratamentos e apresentou difícil controle. A mistura Fluazifop-p-butyl + Fomesafen apresentou melhor controle das plantas daninhas. Os herbicidas ocasionaram fitotoxicidade ao feijão-caupi e redução de área foliar e massa seca de plantas. A produtividade da cultura foi reduzida nos tratamentos com baixo controle de plantas daninhas bem como nos tratamentos que provocaram toxicidade elevada. Conclui-se que o feijão-caupi apresentoutolerância diferencial aos herbicidas nas doses testadas.

Non-destructive identification of physical damage in mung bean (Vigna radiata L. ) seeds by X-ray image analysis / Identificação não destrutiva de danos físicos em sementes de feijão-mungo (Vigna radiata L. ) por análise de imagem de raios-X

Global demand for pulses such as the mung bean has grown in the last years. For successful production of these crops it is necessary to use high quality seeds. Methodologies based on X-ray image analysis have been used as a complementary tool to evaluate the physical quality of seeds due to their speed and potential for automation. The aim of this study was to evaluate the efficiency of X-ray analysis for non-destructive evaluation of the physical quality of Vigna radiata seeds and to relate the variables obtained with their physiological potential. For this, seeds from eight lots were X-rayed and subsequently subject to germination test. In total, 18 physical and physiological parameters were determined. The X-ray image analysis was efficient for evaluating the internal morphology of Vigna radiata seeds and allowed the identification of various damage types. However, it was not possible to relate the physical variables to the seed quality as the lots presented similar germination percentage. Physical variables such as solidity and circularity are related to percentage of root protrusion and length of seedling hypocotyl. Low relative densities indicate deteriorated tissues, related to severe morphological damage and non-viable seeds.

A demanda mundial por leguminosas como o feijão mungo tem crescido nos últimos anos. Para o sucesso da produção destas culturas é necessário a utilização de sementes de alta qualidade. Metodologias baseadas na análise de imagens de raios X têm sido utilizadas como ferramenta complementar para avaliação da qualidade física de sementes em função da sua rapidez e potencial de automatização. O objetivo deste trabalho foi avaliar a eficiência da análise de raios X para avaliação não destrutiva da qualidade física de sementes de Vigna radiata, e relacionar as variáveis obtidas com o seu potencial fisiológico.Para tal, sementes de oito lotes foram radiografadas e submetidas ao teste de germinação. Por meio dessas avaliações foram determinadas 18 variáveis, distribuídas entre físicas e fisiológicas. A análise de imagens de raios X foi eficiente para a avaliação da morfologia interna das sementes Vigna radiata e permitiu a identificação de vários tipos de danos. Porém, não foi possível relacionar as variáveis físicas com a qualidade das sementes, pois os lotes apresentaram porcentagens de germinação semelhantes. Variáveis físicas como solidez e circularidade estão relacionadas com a percentagem de protrusão radicular e o comprimento de hipocótilo das plântulas. Densidades relativas baixas indicam tecidos deteriorados, tendo relação com danos morfológicos graves e sementes inviáveis.

Quality of adzuki bean seeds desiccated with flumioxazin and subjected to storage / Qualidade de sementes de feijão azuki dessecadas com flumioxazin e submetidas ao armazenamento

Production and storage environments influence the physiological and sanitary quality of seeds. This study aimed to evaluate the effects of the herbicide flumioxazin applied as a preharvest desiccant and storage on the physiological and sanitary quality of adzuki bean seeds. A randomized block design was used in a split-plot scheme, with four replications. Plots consisted of five doses of the herbicide flumioxazin (20, 25, 30, 35, and 40 g ai·ha-1) and subplots consisted of two evaluation times (harvest and six months after harvest). Two controls, with no herbicide application, were tested for each evaluation time. The physiological seed quality was maintained with doses from 25 to 35 g·ha-1 of flumioxazin. Increasing herbicide doses reduced the electrical conductivity of seeds. The increased doses also reduced the percentage of normal seedlings in the first germination count after six months of storage and caused seedling vigor loss. The storage of adzuki bean for six months reduced its physiological quality, leading to losses in germination and seed vigor. Storage and increasing doses of the desiccant flumioxazin reduced the incidence of the pathogens Rhizopus, Cladosporium, and Fusarium in the seeds. The increased doses of this herbicide reduced Aspergillus incidence. Penicillium incidence was not affected by treatments.(AU)

A qualidade fisiológica e sanitária de sementes é influenciada pelo ambiente de produção e de armazenamento. Neste trabalho objetivou-se avaliar os efeitos do herbicida flumioxazin aplicado como dessecante em pré-colheita e do armazenamento sobre a qualidade fisiológica e sanitária de sementes de feijão azuki. Foi adotado o delineamento experimental em blocos ao acaso, em esquema de parcelas subdivididas. Nas parcelas foram alocadas as cinco doses do herbicida flumioxazin (20, 25, 30, 35 e 40 g i.a·ha-1) e nas subparcelas as duas épocas de avaliação (colheita e 6 meses após a colheita), com quatro repetições. Foram testados dois tratamentos sem aplicação do herbicida para cada época de avaliação. Nas doses entre 25 a 35 g·ha-1 de flumioxazin observou-se a manutenção da qualidade fisiológica das sementes. Em doses crescentes reduziu-se a condutividade elétrica das sementes. O aumento das doses reduziu a porcentagem de plântulas normais na primeira contagem da germinação, após seis meses de armazenamento, e causou perda no vigor das plântulas. O armazenamento de feijão azuki durante seis meses reduziu a qualidade fisiológica, causando perdas na germinação e vigor das sementes. O armazenamento e o aumento das doses do dessecante flumioxazin reduziram a incidência dos patógenos Rhizopus, Cladosporium e Fusarium nas sementes. O aumento das doses reduziu a incidência de Aspergillus. A incidência de Penicillium não foi afetada pelos tratamentos.(AU)

Population parameters as a way to evaluate the risk of attack of Aphis craccivora (Hemiptera: Aphididae) on cowpea / Parâmetros populacionais como forma de avaliar os riscos de ataque de Aphis craccivora (Hemiptera: Aphididae) em feijão-caupi

The objective of this research was to develop fertility life tables in order to estimate the population parameters of black aphid (Aphis craccivora Koch) in cowpea (Vigna unguiculata) varieties, aiming to propose a risk scale for its use. The experiment consisted of six treatments and six replicates (five varieties plus the cultivar VITA 7 as a susceptible control). A cohort was formed with six adult females distributed in six replicates of each genotype, and the insects were observed daily. Based on the data, fertility life tables were drawn for each variety and the population parameters were estimated. The different values of the finite growth rate (λ) were considered to propose a risk scale for the use of the genotypes. The results obtained give the dimension of the variability of V. unguiculata in respect to the character, resistance to A. craccivora, with antibiosis as the main mechanism of resistance. Considering all the results, the varieties studied can be classified according to their suitability as a plant favorable to the development of the black aphid as follows: VITA 7 > CE-13 > CE-51 > CE-08 = CE-07. The proposal of a risk scale for the use of V. unguiculata genotypes against the A. craccivora population, based on the finite growth rate (λ) values, was adequate to discriminate the varieties studied.(AU)

Objetivou-se nesta pesquisa elaborar tabelas de vida de fertilidade com o intuito de estimar os parâmetros populacionais de pulgão-preto (Aphis craccivora Koch) em variedades de feijão-caupi (Vigna unguiculata), visando propor uma escala de risco para o seu uso. O experimento constituiu-se em seis tratamentos (cinco variedades mais o cultivar VITA 7 como padrão de suscetibilidade) com seis repetições. Formou-se uma coorte com seis fêmeas adultas distribuídas em cada genótipo, sendo todos os indivíduos observados diariamente. De posse dos dados, foram elaboradas tabelas de vida de fertilidade para cada variedade e estimados os parâmetros populacionais. Para propor uma escala de risco de uso de genótipos, ponderou-se sob os diferentes valores da razão finita de crescimento (λ). Os resultados obtidos dão a dimensão da variabilidade de V. unguiculata com relação ao caráter da resistência a A. craccivora, sendo a antibiose o principal mecanismo de resistência associado. Considerando-se todos os resultados, foi possível hierarquizar as variedades estudadas segundo sua aptidão como planta favorável ao desenvolvimento ao pulgão-preto conforme segue: VITA 7 >> CE-13 > CE-51 > CE-08 = CE-07. A proposta de uma escala de risco do uso de genótipos de V. unguiculata frente à população de A. craccivora, baseada nos valores da razão finita de crescimento (λ), foi adequada para discriminar as variedades estudadas.(AU)

Estimates of genetic divergence in cowpea by multivariate analysis in different environments / Estimativa de divergência genética em feijão-caupi por meio de análise multivariada em diferentes ambientes

Cowpea is a legume of great importance in the Brazilian nutrition, mainly in the Northeast region. Despite the low yield of Brazilian cowpea, the species presents a genetic potential to be explored. Thus, this work aimed to characterize the genetic diversity of cowpea genotypes by agronomic traits and select genotypes for possible crosses by multivariate analysis. Four value for cultivation and use tests were carried out with cowpea genotypes in 2005 and 2006, in the municipalities of Aquidauana, Chapadão do Sul, and Dourados, in the state of Mato Grosso do Sul. The experimental design was a complete randomized block with 20 genotypes and four replications. The evaluated traits were value for cultivation, plant lodging, pod length, grain weight of five pods, number of grains per pod, pod weight, severity of powdery mildew, and grain yield. To estimate the genetic diversity among the genotypes, the optimization methods of Tocher and UPGMA were used. The generalized distance of Mahalanobis was used as a dissimilarity measure. The clustering methods revealed genetic variability among the cowpea genotypes evaluated. The methods used formed a different number of groups for each environment. Genotypes TE97-309G-24, MNC99-542F-5, BRS Paraguaçu, BRS Paraguaçu, BR 17-Gurguéia, and CNC x 409-11F-P2 can be used to obtain promising combinations and high genetic variability.

O feijão-caupi é de grande importância na nutrição brasileira, principalmente na região Nordeste. Apesar do baixo rendimento do feijão-caupi no Brasil, esta leguminosa apresenta potencial genético a ser explorado. Dessa forma, o objetivo do trabalho foi caracterizar a variabilidade genética de caracteres agronômicos e estimar a divergência genética entre genótipos de feijão-caupi por meio de análise multivariada. Quatro ensaios de valor de cultivo e uso com genótipos de feijão-caupi foram conduzidos nos anos de 2005 e 2006, nos municípios de Aquidauana, Chapadão do Sul e Dourados. Os experimentos foram conduzidos em delineamento blocos casualizados, com 20 genótipos e quatro repetições. Os caracteres avaliados foram acamamento de plantas, comprimento de vagem, peso de grãos de cinco vagens, número de grãos por vagem, peso de vagem e produtividade de grãos. Realizou-se análise de variância individual e conjunta. Para estimar a diversidade genética entre os genótipos, foram utilizados o métodos de otimização de Tocher e UPGMA. A distância generalizada de Mahalanobis foi utilizada como medida de dissimilaridade. Foi possível detectar variabilidade genética entre os genótipos de feijão-caupi avaliados por meio dos métodos de agrupamento utilizados. Os métodos utilizados formaram números de grupos distintos para cada ambiente. Os genótipos TE97-309G-24, MNC99-542F-5, BRS Paraguaçu, BRS Paraguaçu, BR 17-Gurguéia e CNC x 409-11F-P2 podem ser usados para obter combinações promissoras e elevada variabilidade genética.

Accumulation of macronutrients in cowpea and weeds in competition and under soil water deficit / Acumulação de macronutrientes em feijão-caupi e plantas daninhas em competição e sob déficit hídrico no solo

The ability of a plant species to succeed in colonization of agroecosystem depends on its efficiency in the use of growth resources even in deficient conditions. The present study aimed to evaluate the effects of competition and water deficit in the soil on the accumulation of macronutrients of Vigna unguiculataL. Walp., Commelina benghalensis L. and Waltheria indica L. The study was conducted in a greenhouse, in randomized block design, with four replications. The treatments were arranged in a 5 × 2 factorial, with the first factor corresponding to types of interaction among species (V. unguiculata + C. benghalensis; V. unguiculata + W. indica; V. unguiculata in monoculture, C. benghalensis in monoculture and W. indica in monoculture), and the second of water regimes (irrigated and water deficit).The water deficit differently affects macronutrient content on the species, with decreased of K, Ca and Mg in cowpea, and N, P, K and Ca in W. indica. For C. benghalensis, the water deficit does not reduce the macronutrient contents on the plant. The competition between plants intensifies the effects of water deficit only on C. benghalensis, with a decreased on the content of all macronutrients studied. Under irrigated conditions, competition between plants was more damaging the weeds compared to cowpea. The C. benghalensis specie, free from interference, has a high potential for nutrient extraction under irrigated and water deficit regimes.

A capacidade de uma espécie vegetal para ter sucesso na colonização do agroecossistema depende da sua eficiência na utilização dos recursos de crescimento mesmo em condições deficientes. Objetivou-se avaliar os efeitos da competição e déficit hídrico no solo no conteúdo de macronutrientes de feijão-caupi (Vigna unguiculata L. Walp.), trapoeraba (Commelina benghalensis L.) e malva-branca (Waltheria indica L.). Foi conduzido estudo em casa de vegetação, em delineamento em blocos casualizado, com quatro repetições. Os tratamentos foram arranjados em fatorial 5 × 2, com o primeiro fator correspondente aos arranjos de competição entre as espécies (V. unguiculata + C. benghalensis; V. unguiculata + W. indica; V. unguiculataem monocultivo; C. benghalensis em monocultivo e W. indica em monocultivo), e o segundo dos regimes hídricos (irrigado e déficit hídrico). O déficit hídrico afeta de forma diferenciada o conteúdo de macronutrientes nas espécies, com redução de K, Ca e Mg no feijão-caupi, e N, P, K e Ca em W. indica. Para C. benghalensis, o déficit hídrico não reduz os conteúdos de macronutrientes na planta. A competição entre plantas intensifica os efeitos do déficit hídrico apenas em C. benghalensis, com redução do conteúdo de todos os macronutrientes estudados. Em condições irrigadas, a competição entre plantas foi mais prejudicial as plantas daninhas do que o feijão-caupi. Aespécie C. benghalensis, livre de interferência, apresenta elevado potencial de extração de nutrientes sob regimes irrigado e de déficit hídrico.

Saline stress effect on cowpea beans growth under biofertilizer correction / Efeito do estresse salino no crescimento do feijão-caupi sob a correção de biofertilizante

New strategies to increase growth and food crops productivity in saline soils are priorities in the research. The experiment was carried out in a pot to investigate the growth of cowpea cv. Canapu in response to saline stress under the correction of a mixed biofertilizer. Five irrigation water salinity levels and three doses of the mixed biofertilizer were tested, with four replicates at each level. The increase in salinity level resulted in reductions in stem diameter, leaves number, shoot biomass and roots. The mixed biofertilizer use was able to minimize the effect of salinity in all analyzed variables, improving the cowpea growth and development, protecting from saline stress negative impacts. In addition, the mixed biofertilizer use may be an option to improve crop growth and productivity in salt affected soils.

Novas estratégias para aumentar o crescimento e a produtividade de plantas cultivadas em solos salinos representam prioridades na pesquisa. O experimento foi conduzido em vaso, para investigar o crescimento do Feijão-Caupi em resposta ao estresse salino sob a correção de um biofertilizante misto. Cinco níveis de salinidade da água de irrigação e três doses do biofertilizante misto foram testados, com quatro repetições cada nível. O biofertilizante misto foi capaz de minimizar o estresse salino.O aumento do nível de salinidade resultou em reduções no diâmetro do caule, número de folhas, biomassa da parte aérea e das raízes. O uso do biofertilizante misto minimizou o efeito da salinidade em todas as variáveis analisadas, melhorando o crescimento e desenvolvimento do feijão caupi, protegendo-o dos impactos negativos do estresse salino. O uso de biofertilizante misto pode ser uma opção para melhorar o crescimento da cultura e a produtividade em solos afetados por sais.

Adaptability and stability of cowpea genotypes via REML/BLUP and GGE BIPLOT / Adaptabilidade e estabilidade de genótipos de feijão-caupi via REML/BLUP e GGE BIPLOT

Several methodologies have been proposed in order to measure the influence that genotype-by-environment interaction exerts on the various characters of interest. The mixed models using REML/BLUP and GGE Biplot have been mentioned as advantageous to identify superior genotypes. The use of environmental information can be useful to find the factors that are in the real difference between the genotypes. The objective of this study was to compare statistical methodologies for the adaptability and stability analysis of cowpea genotypes in value for cultivation and use testings. The experiments were carried out from March to July 2016 and 2017, in the municipalities of Dourados and Aquidauana. A randomized complete block design was used, with 14 genotypes and four replicates, 12 advanced lines and two commercial cultivars. After detecting significant genotype-by-environment interaction, the adaptability and phenotypic stability of cowpea genotypes were analyzed by the GGE Biplot and REML/BLUP. Both methodologies were concordant in the identification of the best cowpea genotypes for the State of Mato Grosso do Sul. Thegenotypes 6 (Pingo-de-ouro 1-5-4), 10 (Pingo-de-ouro 1-5-10) and 8 (Pingo-de-ouro 1-5-7) are the most suitable to be grown in the State, because they have gathered high grain yield, adaptability and stability.

Diversas metodologias têm sido propostas com o intuito de estimar a influência que a interação genótipos x ambientes exerce sobre os vários caracteres de interesse. Dentre estes modelos mistos via REML/BLUP e GGE-Biplot têm se destacado para identificar genótipos superiores e estratificas ambientes. O uso de informações ambientais pode ser útil para encontrar os fatores que estão na real diferença entre os genótipos. O objetivo deste estudo foi comparar metodologias estatísticas para a análise da adaptabilidade e estabilidade de genótipos de feijão-caupi em ensaios de valor de cultivo e uso. Os experimentos foram realizados no período de Março a Julho de 2016 e 2017, nos municípios de Dourados e Aquidauana, sendo dois anos em Dourados e um ano em Aquidauana. Foi utilizado o delineamento experimental blocos casualizados, com 14 genótipos e quatro repetições, sendo 12 linhagens avançadas e duas cultivares comerciais. Depois de detectar a interação significativa entre genótipos e ambientes, a adaptabilidade e a estabilidade fenotípica dos genótipos de feijão-caupi foram analisadas pelos métodos GGE-Biplot e REML/BLUP. Os dois métodos foram concordantes em 80% na identificação dos melhores genótipos de feijão-caupi para o Estado de Mato Grosso do Sul. Os genótipos Pingo-de-ouro 1-5-4, Pingo-de-ouro 1-5-10 e Pingo-de-ouro 1-5-7, foram os genótipos que apresentaram simultaneamente alta produtividade de grãos, adaptabilidade e estabilidade, sendo assim indicados para o cultivo no Mato Grosso do Sul.

Efeito da concentração de polpa de graviola (Annona muricata L.) sobre a fermentação de mosto ácido de mel suplementado com extrato de feijão caupi (Vigna unguiculatana L. Walp.) para a produção de hidromel / Effect of graviola pulp concentration (Annona muricata L.) on fermentation of honey acid wort supplemented with caupi bean extract (Vigna unguiculatana L. Walp.) for the production of mead

O hidromel é uma bebida oriunda da fermentação alcoólica de mosto de mel e alguns adjuntos, como as frutas, para o fornecimento de nutrientes essenciais à fermentação. A graviola e o feijão caupi são importantes matérias-primas vegetais brasileiras, que constituem importantes fontes de carboidratos, proteínas, sais minerais e outros compostos. Assim, o presente trabalho teve como objetivo avaliar o efeito da suplementação de mostos de mel, com concentração fixa de feijão caupi (30 g.L-1) e diferentes concentrações de graviola (0, 10 e 30% m/m), sobre a fermentação dos mesmos, avaliando os perfis de concentração celular e dos teores de sólidos solúveis totais e etanol. Diante dos resultados obtidos foi possível observar que a graviola pode ser considerada um bom suplemento para o estímulo da fermentação de mostos de mel por leveduras.

Thermal requirements and age-specific life tables of cowpea aphids in cowpea under natural field conditions / Exigências térmicas e tabelas de expectativa de vida específicas para pulgão preto em feijão-caupi sob condições naturais de campo

Thermal requirements and life tables of insects are important tools in the ecological management of pests. Thus, this study aimed to construct age-specific life tables for Aphis craccivora at different times of the year and, based on their thermal requirements, predict the occurrence of adults under field conditions. To that end, aphids of known age were kept in cages over cowpea plants at different times of the year - November 2016 and March, April, and June 2017 - at the Agricultural Sciences Center of the Federal University of Piauí. Parameters of development, fertility, and mortality were observed daily, allowing us to construct age-specific life tables, as well as an accumulated degree-day model to predict adult occurrence. The time of year affected the first and second stages of development of the cowpea aphid, the nymphal and reproductive periods, longevity, the biological cycle, the number of nymphs produced per female, the daily production of nymphs per female, life expectancy (ex), and survival (Lx). However, the fertility life tables showed significant differences only in the net reproduction rate (R0). The proposed degree-day model reached an accuracy of one day or more than the observed value, with a maximum error of 12.9%. We concluded that the proposed model is adequate to predict the occurrence of adults in the field and that the population parameters of A. craccivora in cowpea are negatively affected during November and positively affected in June.(AU)

As exigências térmicas dos insetos, bem como as tabelas de vida, são ferramentas importantes para o manejo ecológico de pragas. Assim, objetivou-se elaborar as tabelas de expectativa de vida específicas para Aphis craccivora em diferentes épocas do ano e, como base em suas exigências térmicas, prever a ocorrência de adultos em condições de campo. Para isso, pulgões de idade conhecida foram mantidos em gaiolas sobre feijão-caupi em diferentes épocas do ano, novembro de 2016 e março, abril e junho de 2017, no Centro de Ciências Agrárias da Universidade Federal do Piauí. Os parâmetros de desenvolvimento, fertilidade e mortalidade foram observados diariamente, permitindo a elaboração das tabelas de expectativa de vida, bem como a obtenção dos Graus-dia acumulados para a predição de ocorrência adulta. A época do ano afetou significativamente o primeiro e o segundo estádio de desenvolvimento do pulgão-preto-do-caupi, bem como os períodos ninfal e reprodutivo, a longevidade, ciclo biológico, o número de ninfas produzidas por fêmea e a produção diária de ninfas por fêmea, bem como a expectativa de vida (ex) e sobrevivência (Lx). No entanto, para as tabelas de vida de fertilidade, só houve diferenças estatísticas para a taxa líquida de reprodução (Ro). O modelo Graus-dia proposto obteve uma precisão de um dia ou mais do que o valor observado, com erro máximo de 12,9%. Concluiu-se que o modelo proposto é adequado para predizer a ocorrência de adultos no campo e que os parâmetros populacionais de A. craccivora em feijão-caupi são afetados negativamente durante o mês de novembro e positivamente em junho.(AU)

Thermal requirements, life expectancy and fertility tables of Aphis craccivora (Hemiptera: Aphididae) in Vigna unguiculata (Fabales: Fabaceae) under laboratory conditions / Exigências térmicas e tabelas de esperança de vida e fertilidade de Aphis craccivora (Hemiptera: Aphididae) em Vigna unguiculata (Fabales: Fabaceae) sob condições de laboratório

The objective of this research was to determine the thermal requirements and develop life expectancy and fertility tables of Aphis craccivora (L.) in Vigna unguiculata (Walp.). The insects were kept in Petri dishes and fed V. unguiculata leaf discs (cultivar BRS-Tumucumaque) under five constant temperatures (18, 22, 25, 28 and 31ºC). Live and dead insects and stages of development; the onset and duration of the pre-reproductive, reproductive and post-reproductive periods; the number of nymphs per female; and the longevity of the adults were quantified daily. Based on these observations, fertility life expectancy tables were developed, and the thermal requirements of the cowpea black-aphid were determined. Increased temperature influenced all stages of insect development, as well as the pre-reproductive and post-reproductive periods and the total number of nymphs per female. The base temperature for development was 9.13ºC with thermal development constant of 99.0 GD. The highest net reproduction rate (Ro) was at 25ºC. At 28ºC, the greatest capacity to increase in number (rm) was observed, as well as the highest finite rate of increase (λ) and the shortest time to double in number (TD). The thermal range between 22 and 28ºC can be considered most favourable to the development of A. ­craccivora in V. unguiculata. Temperatures below 22 and above 28ºC affect the fertility and survival of cowpea black-aphids. Increased temperature induces reproduction and reduces the longevity and life expectancy of A. craccivora in cowpeas.(AU)

Objetivou-se com esta pesquisa determinar as exigências térmicas e elaborar as tabelas de esperança de vida e de fertilidade de Aphis craccivora (L.) em Vigna unguiculata (Walp.). Os insetos foram mantidos em placas de Petri, alimentados com discos foliares de V. unguiculata, cultivar BRS-Tumucumaque, sob 5 temperaturas constantes: 18, 22, 25, 28 e 31ºC. Diariamente, foram quantificados os insetos vivos e mortos, o estádio de desenvolvimento, bem como o início e a duração dos períodos pré-reprodutivo, reprodutivo e pós-reprodutivo, o número de ninfas por fêmea e a longevidade de adultos. Com base nessas observações, elaboraram-se as tabelas de esperança de vida de fertilidade e determinaram-se as exigências térmicas do pulgão-preto do caupi. O aumento da temperatura influenciou todos os estádios de desenvolvimento do inseto, bem como os períodos pré-reprodutivo e pós-reprodutivo e o número total de ninfas por fêmea. A temperatura base de desenvolvimento foi de 9,13ºC, e a constante térmica de desenvolvimento, de 99,0 GD. A maior taxa líquida de reprodução (Ro) foi a 25ºC. A 28ºC, constatou-se a maior capacidade de aumentar em número (rm), bem como a maior razão finita de aumento (λ) e menor tempo para duplicar em número (TD). Pode-se considerar que a faixa térmica mais favorável ao desenvolvimento de A. craccivora em V. unguiculata está entre 22 e 28ºC. Temperaturas abaixo de 22 e acima de 28ºC prejudicam a fertilidade e a sobrevivência do pulgão-preto do caupi. O aumento da temperatura antecipa a reprodução e reduz a longevidade e esperança de vida de A. craccivora em feijão-caupi.(AU)

Changes induced by co-inoculation in nitrogen-carbon metabolism in cowpea under salinity stress

ABSTRACT To mitigate the deleterious effects of abiotic stress, the use of plant growth-promoting bacteria along with diazotrophic bacteria has been increasing. The objectives of this study were to investigate the key enzymes related to nitrogen and carbon metabolism in the biological nitrogen fixation process and to elucidate the activities of these enzymes by the synergistic interaction between Bradyrhizobium and plant growth-promoting bacteria in the absence and presence of salt stress. Cowpea plants were cultivated under axenic conditions, inoculated with Bradyrhizobium and co-inoculated with Bradyrhizobium sp. and Actinomadura sp., Bradyrhizobium sp. and Bacillus sp., Bradyrhizobium sp. and Paenibacillus graminis, and Bradyrhizobium sp. and Streptomycessp.; the plants were also maintained in the absence (control) and presence of salt stress (50 mmolL-1 NaCl). Salinity reduced the amino acids, free ammonia, ureides, proteins and total nitrogen content in nodules and increased the levels of sucrose and soluble sugars. The co-inoculations responded differently to the activity of glutamine synthetase enzymes under salt stress, as well as glutamate synthase, glutamate dehydrogenase aminating, and acid invertase in the control and salt stress. Considering the development conditions of this experiment, co-inoculation with Bradyrhizobium sp. and Bacillus sp. in cowpea provided better symbiotic performance, mitigating the deleterious effects of salt stress.

Genomic identification and characterization of the elite strains Bradyrhizobium yuanmingense BR 3267 and Bradyrhizobium pachyrhizi BR 3262 recommended for cowpea inoculation in Brazil

ABSTRACT The leguminous inoculation with nodule-inducing bacteria that perform biological nitrogen fixation is a good example of an "eco-friendly agricultural practice". Bradyrhizobium strains BR 3267 and BR 3262 are recommended for cowpea (Vigna unguiculata) inoculation in Brazil and showed remarkable responses; nevertheless neither strain was characterized at species level, which is our goal in the present work using a polyphasic approach. The strains presented the typical phenotype of Bradyrhizobium with a slow growth and a white colony on yeast extract-mannitol medium. Strain BR 3267 was more versatile in its use of carbon sources compared to BR 3262. The fatty acid composition of BR 3267 was similar to the type strain of Bradyrhizobium yuanmingense; while BR 3262 was similar to Bradyrhizobium elkanii and Bradyrhizobium pachyrhizi. Phylogenetic analyses based on 16S rRNA and three housekeeping genes placed both strains within the genus Bradyrhizobium: strain BR 3267 was closest to B. yuanmingense and BR 3262 to B. pachyrhizi. Genome average nucleotide identity and DNA-DNA reassociation confirmed the genomic identification of B. yuanmingense BR 3267 and B. pachyrhizi BR 3262. The nodC and nifH gene analyses showed that strains BR 3267 and BR 3262 hold divergent symbiotic genes. In summary, the results indicate that cowpea can establish effective symbiosis with divergent bradyrhizobia isolated from Brazilian soils.

Antioxidant response of cowpea co-inoculated with plant growth-promoting bacteria under salt stress

Abstract Soil salinity is an important abiotic stress worldwide, and salt-induced oxidative stress can have detrimental effects on the biological nitrogen fixation. We hypothesized that co-inoculation of cowpea plants with Bradyrhizobium and plant growth-promoting bacteria would minimize the deleterious effects of salt stress via the induction of enzymatic and non-enzymatic antioxidative protection. To test our hypothesis, cowpea seeds were inoculated with Bradyrhizobium or co-inoculated with Bradyrhizobium and plant growth-promoting bacteria and then submitted to salt stress. Afterward, the cowpea nodules were collected, and the levels of hydrogen peroxide; lipid peroxidation; total, reduced and oxidized forms of ascorbate and glutathione; and superoxide dismutase, catalase and phenol peroxidase activities were evaluated. The sodium and potassium ion concentrations were measured in shoot samples. Cowpea plants did not present significant differences in sodium and potassium levels when grown under non-saline conditions, but sodium content was strongly increased under salt stress conditions. Under non-saline and salt stress conditions, plants co-inoculated with Bradyrhizobium and Actinomadura or co-inoculated with Bradyrhizobium and Paenibacillus graminis showed lower hydrogen peroxide content in their nodules, whereas lipid peroxidation was increased by 31% in plants that were subjected to salt stress. Furthermore, cowpea nodules co-inoculated with Bradyrhizobium and plant growth-promoting bacteria and exposed to salt stress displayed significant alterations in the total, reduced and oxidized forms of ascorbate and glutathione. Inoculation with Bradyrhizobium and plant growth-promoting bacteria induced increased superoxide dismutase, catalase and phenol peroxidase activities in the nodules of cowpea plants exposed to salt stress. The catalase activity in plants co-inoculated with Bradyrhizobium and Streptomyces was 55% greater than in plants inoculated with Bradyrhizobium alone, and this value was remarkably greater than that in the other treatments. These results reinforce the beneficial effects of plant growth-promoting bacteria on the antioxidant system that detoxifies reactive oxygen species. We concluded that the combination of Bradyrhizobium and plant growth-promoting bacteria induces positive responses for coping with salt-induced oxidative stress in cowpea nodules, mainly in plants co-inoculated with Bradyrhizobium and P. graminis or co-inoculated with Bradyrhizobium and Bacillus.