O tamanho de sementes de feijão afeta a utilização das reservas armazenadas durante a germinação / Seed size of common bean affects the utilization of stored reserves during germination

O objetivo do presente estudo foi avaliar a qualidade fisiológica de sementes defeijão com diferentes tamanhos, identificando a relação do tamanho da semente com a mobilização e utilização de reservas. Foram utilizadas sementes da cultivar comercial IPR-88 Uirapuru e Iapar 81 padronizadas e posteriormente, determinadas três frações a partir de pesagem individual, sendo: sementes pequenas, médias e grandes. A qualidade fisiológica das três frações foi determinada pelo teste de germinação e pelos testes de vigor: envelhecimento acelerado e teste de desempenho de plântulas (comprimento). A mobilização e utilização de reservas foi mensurada aos cinco dias de hidratação das sementes, onde foram avaliadas massa seca, taxa de mobilização de reservas, taxa de redução de reservas e eficiência de uso das reservas. Os resultados demonstraram que não houve diferença entre as frações na porcentagem de germinação e envelhecimento acelerado. Considerando os parâmetros que avaliaram a mobilização e utilização de reservas, verificou-se que sementes de maior tamanho formam plântulas de maior massa seca, no entanto, tem menor taxa de mobilização de reservas e menor eficiência de uso de suas reservas. Desta forma, evidencia-se que o tamanho da semente influencia a mobilização e utilização de reservas, de maneira que sementes da fração média e pequena apresentam maior eficiência de uso de reservas até os cinco dias de germinação.(AU)

The objective of the present study was to evaluate the physiological quality of bean seeds with different sizes, identifying the relationship of seed size with the mobilization and utilization of reserves in bean seeds. Seeds of the commercial cultivarIPR-88 Uirapuru and Iapar 81 were standardized and subsequently, three fractions were determined from individual weighing, being: small medium and large seeds. The physiological quality of the three fractions was determined by germination test, accelerated aging vigor test, and seedling performance (length) test. Reserve mobilization and utilization was measured at five days of seed hydration, where dry mass, reserve mobilization rate, reserve reduction rate, and reserve use efficiency were evaluated. The results showed that there was no difference between the fractions in the percentage of germination and accelerated aging. Considering the parameters that evaluated the mobilization and use of reserves, it was found that larger seeds form seedlings with greater dry mass, however, have lower rate of reserve mobilization and lower efficiency of use of their reserves. Thus, it is evident that the size of the seed influences the mobilization and use of reserves, so that seeds of the medium and small fraction present higher reserve use efficiency at five days of germination.(AU)

Genotypic selection of pre-clultivars of carioca and early carioca beans for the Agreste-Sertão of Pernambuco, Brazil / Seleção genotípica de pré-cultivares de feijão carioca e carioca precoce para o Agreste-Sertão de Pernambuco, Brasil

ABSTRACT: Genotype x environment interactions represent a major challenge in identifying and selecting genotypes responsive to different climate and soil conditions. This research evaluated and selected pre-cultivars of carioca bean and early carioca bean based on adaptability, stability, and grain yield. In the 2014 crop season, two regional competition trials were conducted in the state of Pernambuco: carioca beans (14 genotypes in Arcoverde, Belém de São Francisco, Caruaru and São João) and early carioca beans (11 genotypes in Araripina, Arcoverde, and Caruaru) and, in the 2015 crop season, with early carioca beans (11 genotypes in Araripina, Arcoverde, and Brejão). Parameters were estimated by mixed models, and the selection was performed using the Harmonic Mean of Relative Performance of Genetic Values (HMRPGV) method following three strategies: i) selection based on predicted genetic value with no interaction; ii) selection according to predicted genetic value considering each location; and iii) simultaneous selection for grain yield, adaptability, and stability. The environments influenced the phenotypic expression of the carioca and early carioca bean genotypes, representing a specific adaptation. The genotypes BRS Notável, BRS Estilo and BRS Pérola, of carioca beans, and CNFC 15875, BRS Notável and CNFC 15630, of early carioca beans, had the best results in the environments tested, regarding, simultaneously, adaptability to different soil and climate conditions, performance stability, and grain yield.

RESUMO: A interação genótipo x ambiente representa um grande desafio na identificação e seleção de genótipos responsivos às diversas condições de clima e solo. O objetivo deste trabalho foi avaliar e selecionar pré-cultivares de feijão carioca e feijão carioca precoce com base na adaptabilidade, estabilidade e produtividade de grãos. Na safra 2014 foram conduzidos dois ensaios regionais de competição no estado de Pernambuco: feijão carioca (14 genótipos em Arcoverde, Belém de São Francisco, Caruaru e São João) e feijão carioca precoce (11 genótipos em Araripina, Arcoverde e Caruaru) e na safra de 2015 com feijão carioca precoce (11 genótipos, em Araripina, Arcoverde e Brejão). Os parâmetros foram estimados por meio de modelos mistos e a seleção foi realizada pelo método da Média Harmônica do Desempenho Relativo dos Valores Genéticos (MHPRVG), adotando-se três estratégias: i) seleção com base no valor genético predito, sem interação; ii) seleção com base no valor genético predito, considerando cada local; iii) seleção simultânea quanto à produtividade de grãos, adaptabilidade e estabilidade. Observou-se que os ambientes influenciaram na expressão fenotípica dos genótipos de feijão carioca e carioca precoce, configurando adaptação específica. Os genótipos BRS Notável, BRS Estilo e BRS Pérola, de feijão carioca, e CNFC 15875, BRS Notável e CNFC 15630, de feijão carioca precoce, apresentaram os melhores desempenhos nos ambientes testados, considerando-se, simultaneamente, a adaptabilidade a diferentes condições edafoclimáticas, estabilidade de desempenho e produtividade de grãos.

Genotypic selection of pre-clultivars of carioca and early carioca beans for the Agreste-Sertão of Pernambuco, Brazil / Seleção genotípica de pré-cultivares de feijão carioca e carioca precoce para o Agreste-Sertão de Pernambuco, Brasil

Genotype x environment interactions represent a major challenge in identifying and selecting genotypes responsive to different climate and soil conditions. This research evaluated and selected pre-cultivars of carioca bean and early carioca bean based on adaptability, stability, and grain yield. In the 2014 crop season, two regional competition trials were conducted in the state of Pernambuco: carioca beans (14 genotypes in Arcoverde, Belém de São Francisco, Caruaru and São João) and early carioca beans (11 genotypes in Araripina, Arcoverde, and Caruaru) and, in the 2015 crop season, with early carioca beans (11 genotypes in Araripina, Arcoverde, and Brejão). Parameters were estimated by mixed models, and the selection was performed using the Harmonic Mean of Relative Performance of Genetic Values (HMRPGV) method following three strategies: i) selection based on predicted genetic value with no interaction; ii) selection according to predicted genetic value considering each location; and iii) simultaneous selection for grain yield, adaptability, and stability. The environments influenced the phenotypic expression of the carioca and early carioca bean genotypes, representing a specific adaptation. The genotypes BRS Notável, BRS Estilo and BRS Pérola, of carioca beans, and CNFC 15875, BRS Notável and CNFC 15630, of early carioca beans, had the best results in the environments tested, regarding, simultaneously, adaptability to different soil and climate conditions, performance stability, and grain yield.

A interação genótipo x ambiente representa um grande desafio na identificação e seleção de genótipos responsivos às diversas condições de clima e solo. O objetivo deste trabalho foi avaliar e selecionar pré-cultivares de feijão carioca e feijão carioca precoce com base na adaptabilidade, estabilidade e produtividade de grãos. Na safra 2014 foram conduzidos dois ensaios regionais de competição no estado de Pernambuco: feijão carioca (14 genótipos em Arcoverde, Belém de São Francisco, Caruaru e São João) e feijão carioca precoce (11 genótipos em Araripina, Arcoverde e Caruaru) e na safra de 2015 com feijão carioca precoce (11 genótipos, em Araripina, Arcoverde e Brejão). Os parâmetros foram estimados por meio de modelos mistos e a seleção foi realizada pelo método da Média Harmônica do Desempenho Relativo dos Valores Genéticos (MHPRVG), adotando-se três estratégias: i) seleção com base no valor genético predito, sem interação; ii) seleção com base no valor genético predito, considerando cada local; iii) seleção simultânea quanto à produtividade de grãos, adaptabilidade e estabilidade. Observou-se que os ambientes influenciaram na expressão fenotípica dos genótipos de feijão carioca e carioca precoce, configurando adaptação específica. Os genótipos BRS Notável, BRS Estilo e BRS Pérola, de feijão carioca, e CNFC 15875, BRS Notável e CNFC 15630, de feijão carioca precoce, apresentaram os melhores desempenhos nos ambientes testados, considerando-se, simultaneamente, a adaptabilidade a diferentes condições edafoclimáticas, estabilidade de desempenho e produtividade de grãos

Environmental variability in simultaneous selection of common bean for grain quality and mineral concentration traits

The selection of common bean (Phaseolus vulgaris L.) lines based on grain quality and mineral concentration traits will be more efficient if a minimum number of experiments is established. This study was carried out to determine whether grain quality and mineral concentration traits are significantly affected by the genotype × environment interaction; to estimate heritability and genetic gain in individual and combined experiments; and to select superior common bean lines considering a minimum number of experiments. A total of 17 common bean genotypes were evaluated in four experiments. Grain quality was determined through seven traits, and the concentration of six minerals was analyzed by acid digestion. Statistical analyses were completed using data obtained from both individual (I, II, III and IV) and combined (I and II; I, II and III; and I, II, III and IV) experiments. Except for the potassium concentration, all traits showed a significant genotype × environment interaction effect. Heritability and genetic gain estimates of grain quality and mineral concentration traits varied when the data were obtained from one or more experiments. Genetic gain may be inflated because of the data being based on one or two experiments. Four carioca bean (BRS MG Uai, LP 09-33, LEC 01-16 and Pérola) and four black bean (TB 02-19, CHP 04-239-52, TB 03-11 and IAC Netuno) genotypes were selected for their high grain quality and mineral concentration based on four experiments. Data from at least four experiments should be used to select common bean lines superior in grain quality and mineral concentration traits to increase the efficiency of simultaneous selection.

Environmental variability in indirect selection for grain yield in common bean lines

An approach to the number of experiments that should be used in correlation analyses aimed at increasing efficiency in indirect selection for grain yield is unprecedented for common bean (Phaseolus vulgaris L.). We hypothesize that trait correlation estimates vary in response to the growing environment. This study was undertaken to investigate the correlations between plant architecture and yield traits in common bean lines and to determine the minimum number of experiments required by Pearson's linear correlation analysis to increase efficiency in indirect selection for grain yield. Seventeen common bean genotypes were evaluated for 17 agronomic traits in four experiments. Pearson's linear correlation analyses were carried out using data from individual experiments and different combinations of growing seasons and years. Ten out of the 17 agronomic traits showed a significant genotype × environment interaction effect, meaning that common bean genotypes exhibited variation for most of the traits evaluated in different growing seasons and years, which resulted in changes in the correlation estimates between these traits. Pearson's linear correlation estimates obtained between plant architecture and yield traits varied in significance, magnitude, and sign when data from individual experiments and combinations of growing seasons and years were considered. The number of grains per pod is the most promising agronomic trait used in indirect selection for grain yield in common bean lines. Data from at least three experiments should be used in Pearson's linear correlation analysis to achieve greater efficiency in indirect selection for grain yield in common bean lines.

Irrigation management of common bean cultivars with contrasting growth habits

A study was undertaken comparing the water requirements of two common bean ( Phaseolus vulgaris L.) cultivars to generate specific recommendations aimed at optimizing water use. To accomplish this work, the agronomic performance, responsiveness to water and water productivity of these two common bean cultivars of determinate and indeterminate growth habits were identified. The 2-year experiment was carried out during the winter growing season in the southeast of Brazil. Cultivars IAC Imperador, with an early season of determinate growth habit, and IPR Campos Gerais, having a mid-season of indeterminate growth habit, were subjected to five irrigation levels (54, 70, 77, 100, and 132 % of the crop evapotranspiration). Water deficit affected agronomic performance, reducing plant height (by up to 29 %), leaf area index (by up to 40 %), soil cover fraction (by up to 28 %), and grain yield (GY - by up to 31 %), in both cultivars. In contrast, excess water was more detrimental to cultivar IAC Imperador. Cultivar IPR Campos Gerais produced 18 % more than GY, showing superior water productivity and response to irrigation depth than IAC Imperador. Out of all the variables evaluated, the soil cover fraction correlated the most with grain yield in both common bean cultivars during the 2-year study. In other words, cover fraction evaluation in common bean allows for estimating crop production potential, which helps producers and technicians in their decision making regarding management practices. Thus, a cultivar directly affects water use in common bean production, thereby suggesting the need for a or water conservation strategy and sustainability of irrigated common bean production.(AU)

Crescimento, severidade de oídio e produtividade do feijão-vagem em resposta a diferentes fontes de potássio / Growth, powdery mildew severity and yield of green beans in response to potassium sources

O Brasil tem enfrentado sérios problemas com o abastecimento de fertilizantes potássicos nos últimos anos. Isso tem causado a elevação dos preços e até mesmo escassez do principal fertilizante potássico utilizado pelos produtores, o cloreto de potássio. Por isso, o objetivo do presente trabalho foi avaliar um silicato de potássio nacional (K6) como fonte alternativa ao uso do cloreto de potássio para a cultura do feijão-vagem. Para tanto, sementes de feijão-vagem cv. Macarrão Rasteiro foram semeadas a campo em espaçamento de 0,50 x 0,20 m. Empregou-se o delineamento em blocos ao acaso com quatro tratamentos e cinco repetições. Os tratamentos foram constituídos da seguinte maneira: (i) testemunha ­ sem adubação potássica; (ii) cloreto de potássio; (iii) silicato de potássio ­ K6; (iv) 50% cloreto de potássio + 50% K6. Os fertilizantes foram aplicados no momento da semeadura e as doses determinadas com base na análise de solo e nas recomendações para a cultura. Foi realizada avaliação de altura de plantas, massa fresca e seca da parte aérea, massa fresca e seca de vagens, estimativa de produtividade e ocorrência de oídio, através de notas de severidade. Verificou-se que não houve influência da adubação potássica sobre o crescimento das plantas. De maneira geral, a produtividade de vagens apresentou baixa influência da adubação. Entretanto, a produtividade total de vagens foi maior em plantas adubadas com K6 em comparação a plantas adubadas com cloreto de potássio. A aplicação de K6 também contribuiu para a redução da severidade de oídio. Dessa forma, nós concluímos que o K6 é uma fonte de potássio viável em substituição ao cloreto de potássio para o feijão-vagem. (AU)

Brazil has faced serious problems with the supply of potassium fertilizers in recent years. This has caused prices to rise and even shortages of the main potassium fertilizer used by producers, potassium chloride. Therefore, the objective of the present work was to evaluate a national potassium silicate (K6) as an alternative source to the use of potassium chloride for the green beans crop. For this purpose, green beans seeds cv. Macarrão Rasteiro were sown in the field at a spacing of 0.50 x 0.20 m. A randomized block design with four treatments and five replications was used. The treatments were constituted as follows: (i) control ­ without potassium fertilization; (ii) potassium chloride; (iii) potassium silicate - K6; (iv) 50% potassium chloride + 50% K6. Fertilizers were applied at the time of sowing and doses were determined based on soil analysis and recommendations for the crop. Plant height, shoot fresh and dry mass, pod fresh and dry mass, yield estimation and occurrence of powdery mildew were evaluated through severity scores. It was found that in terms of plant growth, there was no influence of potassium fertilization on plant growth. In addition, pod productivity showed a reduction throughout the evaluation period and little influence of fertilization. However, total pod productivity was higher in plants that received K6 compared to plants fertilized with potassium chloride. The application of K6 also contributed to the reduction of powdery mildew severity. Thus, we conclude that K6 is a viable source of potassium in substitution of potassium chloride for the green beans.(AU)

Selection of parents and segregating populations of carioca common bean resistant to Fusarium wilt / Seleção de genitores e populações segregantes de feijão carioca resistentes à murcha de fusário

Fusarium wilt (Fusarium oxysporum f. sp. phaseoli) is one of the most common diseases in the common bean (Phaseolus vulgaris) crop, and the most viable alternative for its control is the use of resistant cultivars. However, the number of "carioca" cultivars, the most important commercial group in Brazil, which has a good level of resistance to this disease, is still low. To obtain populations with a higher degree of resistance, seven parents with different levels of resistance to Fusarium and which produce carioca grains were crossed in a complete diallel design. The 21 segregating populations obtained were evaluated in the years/generations 2012/F3, 2013/F4, and 2014/F5 in experiments in Santo Antônio de Goiás, GO, in the winter crop season (sowing in May), together with the check cultivars BRS Notável (resistant) and BRS Cometa (susceptible) in an area naturally infested with Fusarium oxysporum f. sp. phaseoli, under a center pivot irrigation system. Reaction to Fusarium wilt, yield, and 100-seed weight were evaluated. Additive and non-additive effects contributed to control of reaction to Fusarium wilt, yield, and 100-seed weight. The statistically negative general combining ability (gi) estimates for BRS Notável (-0.51), CNFC 15872 (-0.20), IPR Juriti (-0.18), and BRSMG Talismã (-0.13) indicate that these parents are recommended for obtaining populations more resistant to Fusarium wilt. Among them, cultivar BRS Notável also showed a statistically positive gi estimate for grain yield (87.90). Among the parents recommended for resistance to Fusarium wilt, cultivars IPR Juriti (0.99) and BRS Notável (0.23) are those that most contributed to obtaining populations with larger-sized beans. Cultivar BRS Notável is the most promising parent for participation in new crossing blocks, showing non-zero gi estimates for all traits, favoring an increase in resistance to Fusarium wilt, yield, and 100-seed weight. Populations BRS Notável / CNFC 15872, BRS Ametista / BRS Notável, BRS Notável / BRSMG Talismã, and BRS Ametista / BRSMG Talismã showed good mean values for reaction to Fusarium wilt, yield, and 100-seed weight and at least one parent with a good general combining ability estimate for resistance to Fusarium wilt. These four populations are promising for obtaining lines with superior performance for resistance to Fusarium wilt, yield, and larger-sized grains.

A murcha de fusário (Fusarium oxysporum f. sp. phaseoli) é uma das doenças mais importantes para a cultura do feijão (Phaseolus vulgaris) e a alternativa mais viável para o seu controle é a utilização de cultivares resistentes. No entanto, o número de cultivares do grupo comercial carioca, que é o mais importante no Brasil, com bom nível de resistência à essa doença ainda é pequeno. Para a obtenção de populações com maior grau de resistência, sete genitores com diferentes níveis de resistência à murcha de fusário e grãos do tipo carioca foram intercruzados em esquema de dialelo completo. As 21 populações segregantes obtidas foram avaliadas nos anos/gerações 2012/F3, 2013/F4 e 2014/F5, em experimentos em Santo Antônio de Goiás, GO, na época do inverno (semeadura em maio), juntamente com as testemunhas BRS Notável (resistente) e BRS Cometa (suscetível), em área naturalmente infestada com Fusarium oxysporumf. sp. phaseoli, sob irrigação com pivô central. Foram avaliadas a reação à murcha de fusário, produtividade e massa de 100 grãos. Os efeitos aditivos e não aditivos contribuíram no controle da reação à murcha de fusário, produtividade e massa de 100 grãos. As estimativas da capacidade geral de combinação (gi) negativas e diferentes de zero para BRS Notável (-0,51), CNFC 15872 (-0,20), IPR Juriti (-0,18) e BRSMG Talismã (-0,13), indicaram que estes genitores são recomendados para a obtenção de populações mais resistentes à murcha de fusário e entre eles, a cultivar BRS Notável mostrou também estimativa de gi positiva e diferente de zero para produtividade de grãos (87,90). Entre os genitores recomendados para resistência à murcha de fusário, as cultivares IPR Juriti (0,99) e BRS Notável (0,23) são as que mais contribuíram na obtenção de populações com maior tamanho de grãos. A cultivar BRS Notável é o genitor mais promissor para participar de novos blocos de cruzamentos, apresentando estimativas de gi diferentes de zero para todos os caracteres, favorecendo o incremento da resistência à murcha de fusário, produtividade e massa de 100 grãos. As populações BRS Notável / CNFC 15872, BRS Ametista / BRS Notável, BRS Notável / BRSMG Talismã e BRS Ametista / BRSMG Talismã apresentaram boas médias para reação à murcha de fusário, produtividade e massa de 100 grãos, e pelo menos um genitor com boa estimativa da capacidade geral de combinação para resistência à murcha de fusário. Estas quatro populações são promissoras para a obtenção de linhagens superiores para resistência à murcha de fusário, produtividade e maior tamanho de grãos.

Interference and economic damage level of alexandergrass in beans as a function of plant density / Interferência e nível de dano econômico de papuã em feijoeiro em função da densidade de plantas

The study of bean sowing density and the level of economic damage (EDL) caused by alexandergrass (Urochloa plantaginea) are important tools for adequately adopting the integrated management of this weed and, thus, producing food with higher quality and less pesticide residue. Therefore, the objective of this work was to evaluate the interference and the level of the economic damage of alexandergrass in competition with the common bean, estimated as a function of sowing densities of the crop and the weed. The bean cultivar IPR Uirapuru was used. The treatments consisted of four bean densities (140,000; 180,000; 220,000 and 260,000 plants ha-1, respectively) and alexandergrass that varied from 0 to the maximum of 104 plants m-2. The experiment was installed in a Red Aluminoferric Latosol, at the experimental area of the Federal University of the Southern Border, campus Erechim/RS, on 10/31/2016. We used the rectangular hyperbola model to describe the relationship between the loss of bean grain yield and the explanatory variables of plant density (DP), soil cover (CS), leaf area (AF) and shoot dry matter (MS). Therefore, the variables CS and DP can be used instead of AF and MS to estimate grain yield losses in common beans. The density of 260,000 plants ha-1of bean showed greater competitiveness with alexandergrass and the highest values of EDLs, justifying the adoption of weed control management at higher densities.

O estudo da densidade de semeadura do feijoeiro e do nível de dano econômico (NDE) ocasionado pelo papuã (Urochloa plantaginea) são ferramentas importantes para a adoção do manejo integrado dessa planta daninha e, assim, produzir um alimento com maior qualidade e menor resíduo de agrotóxico. Diante disso, objetivou-se com o trabalho avaliar a interferência e o nível de dano econômico do papuã em competição com o feijoeiro, estimados em função de densidades de semeadura da cultura e da planta daninha. Os tratamentos foram compostos por densidades do feijoeiro, cultivar IPR Uirapuru (140.000, 180.000, 220.000 e 260.000 plantas ha-1) e do papuã que variaram de 0 até o máximo de 104 plantas m-2. O experimento foi implantado em um Latossolo Vermelho Aluminoférrico típico na área experimental da Universidade Federal da Fronteira Sul, campus Erechim/RS, em 31/10/2016. Para descrever a relação entre a perda de produtividade de grãos do feijoeiro e as variáveis explicativas; densidade de plantas (DP), cobertura do solo (CS), área foliar (AF) e massa seca da parte aérea (MS), usou-se o modelo da hipérbole retangular. As variáveis CS e DP podem ser usadas em substituição a AF e a MS para estimar as perdas de produtividades de grãos do feijoeiro. A densidade de 260.000 plantas ha-1do feijoeiro apresentou maior competitividade com o papuã e os maiores valores de NDEs, justificando aadoção de medidas de controle da planta daninha em densidades mais elevadas.

Attenuation of salt stress by lycopene on common bean seeds

Salinity is a major abiotic stress that adversely affects several physiological and biochemical aspects of plants. Antioxidants can be used as a potential remediation mechanism to promote plant resilience. Therefore, the objective of the present study was to evaluate increasing doses of the antioxidant lycopene on the germination and initial growth of common bean seedlings under conditions of salt stress. Seeds were treated with the following lycopene concentrations: 0.018; 0.036; 0.072; 0.144; and 0.288 g L-1 and two controls (negative and positive) and evaluated under two growth conditions (without and with salt stress) for physiological quality and pigment content. Data were analyzed by completely randomized design, in 2 x 7 factorial (two growth conditions, with paper towel moistened with water or salt solution x seven treatments, including five lycopene doses and two controls), in four replicates of 50 seeds by concentration. With the results of the analysis of variance, growth conditions (without and with salt stress) were compared by the Tukey test (5%), and the effects of lycopene doses were analyzed by polynomial regression. Lycopene promoted tolerance of bean seeds to salt stress and had a positive influence on the attenuation of salt harmful effects to the initial growth of seedlings, mainly at the doses of 0.072 g L-1 and 0.144 g L-1.(AU)

Influence of common bean genotypes and rhizobia interaction for nodulation and nitrogen fixation / Influência da interação entre genótipos de feijoeiro e rizóbios na nodulação e fixação de nitrogênio

Bacteria from the rhizobia group are able to associate symbiotically with bean crop, forming nodules in the root, in which the biological nitrogen-fixing process occurs. However, the efficiency of this process has been low and it can be attributed to genetic and environmental factors. Thus, the objective of this study was to evaluate the capacity of nodulation of local varieties and commercial common bean cultivars inoculated with a Rhizobium tropici strain used in commercial inoculants and rhizobia isolates from common bean root nodules. The experiment was carried out in a factorial scheme (2x4), in a randomized block design with four replicates. It was tested two local varieties and two commercial cultivars, inoculated with the reference Rhizobium tropicistrain CIAT899 and the RBZ14 strain isolated from common bean nodules grown in soils of Southern Brazil, in adapted Leonard-type pots. The CIAT899 strain promoted either higher mass of viable nodules and higher nitrogen accumulation in the aerial part. The black group local variety showed better response than the cultivar TAA Dama for nodule viability, suggesting more efficiency for nodulation. The interaction between genotypes (local varieties and commercial cultivars) and bacteria showed the specificity of the complex symbiotic relationship of biological nitrogen fixation in common bean, requiring further studies of these interactions.(AU)

As bactérias do grupo rizóbios estão associadas simbioticamente à cultura do feijão, formando nódulos na raiz, nos quais ocorre o processo biológico de fixação do nitrogênio. No entanto, a eficiência desse processo tem sido baixa e pode ser atribuída a fatores genéticos e ambientais. Assim, este estudo teve como objetivo avaliar a capacidade de nodulação de variedades locais e cultivares comerciais de feijão comum inoculadas com uma estirpe de Rhizobium tropiciusada em inoculantes comerciais e isolados de nódulos da raiz do feijão comum. O experimento foi realizado em esquema fatorial (2x4), em delineamento de blocos ao acaso, com quatro repetições. Foram testadas duas variedades locais e duas cultivares comerciais, inoculadascom a estirpe de referência Rhizobium tropiciCIAT899 e o isolado RBZ14 obtido de nódulos de feijão cultivados em solos do sul do Brasil, em vasos adaptados do tipo Leonard. A estirpe CIAT899 promoveu maior massa de nódulos viáveis e maior acúmulo de nitrogênio na parte aérea. A variedade regional do grupo preto apresentou melhor resposta que a cultivar TAA Dama, quanto à viabilidade dos nódulos, sugerindo resposta mais eficiente à nodulação. A interação entre genótipos e bactérias mostrou a especificidade da complexa relação simbiótica da fixação biológica de nitrogênio no feijoeiro, sendo necessário aprofundar os estudos nessas interações.(AU)

Weed coexistence in carioca bean inoculated with Rhizobium tropici or nitrogen-fertilized / Convivência das plantas daninhas no feijão carioca inoculado com Rhizobium tropici ou com adubação nitrogenada

The supply of nitrogen (N) to the carioca bean plant via inoculation with Rhizobium tropici can prevent competition with the weed community by allowing the crop to absorb the nutrient available in the soil. On this basis, this study proposes to examine the period before weed interference (PBI) in the carioca bean plant following inoculation with R. tropici or N topdressing. The experiments were carried out under field conditions during the summer seasons of 2014 and 2015. A randomized-block experimental design with four replicates was adopted, in a 2 × 11 factorial arrangement (common bean plant inoculated or topdressed with N × 11 periods of coexistence with weeds, namely, 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, or 90 days after emergence [DAE]). Nitrogen topdressing increased the crop's tolerance to coexist with weeds from 6 to 14 DAE, compared with inoculation with R. tropici The PBI for the inoculated common bean plant was 24 and 16 DAE in the years 2014 and 2015, respectively. For the N-topdressed plant, the PBI was 30 DAE in both years.(AU)

O fornecimento do nitrogênio ao feijoeiro carioca via inoculação com Rhizobium tropici pode evitar a competição com a comunidade de plantas daninhas pela absorção do nutriente disponível no solo. Portanto, o objeto deste estudo foi avaliar o período anterior à interferência (PAI) no feijoeiro carioca com inoculação com R. tropici e com adubação nitrogenada em cobertura. Os experimentos foram conduzidos em condições de campo durante as safras de verão de 2014 e de 2015. O delineamento experimental foi de blocos casualizados com quatro repetições em esquema fatorial 2x11 (feijoeiro com inoculação ou com adução nitrogenada em cobertura x 11 períodos de convívio com as plantas daninhas: 0, 7, 14, 21, 28, 35, 42, 49, 56, 63 e 90 dias após a emergência (DAE). A adubação nitrogenada em cobertura aumentou a capacidade da cultura em conviver com as plantas daninhas de 6 a 14 DAE quando comparada a inoculação com R. tropici. O PAI para o feijoeiro inoculado foi de 24 e 16 DAE em 2014 e 2015, respectivamente. Para o feijoeiro com adubação nitrogenada em cobertura o PAI foi de 30 DAE em ambos os anos.(AU)

Germination test in carioca bean seeds chemically treated with the use of alternative substrates / Teste de germinação em sementes de feijão carioca tratadas quimicamente com uso de substratos alternativos

The use of quality seeds is a key element for the success of carioca bean (Phaseolus vulgaris L.) cultivation. To avoid or reduce various problems of importance to the crop, it facilitates the achievement of the cultivar's productive potential and the reduction of production costs. Thus, the objective of this work is to identify which conditions are suitable for evaluating germination in bean seeds using different substrates. The treatments were subjected to a temperature of 25°C analyzing five substrates (germitest® paper; germitest® paper + sand; germitest® paper + soil; germitest® paper + charcoal and germitest® paper + vermiculite). The chemicals used were: Cruiser 350 FS, Fortenza 600 FS, Standak Top and Avicta complete. The most suitable substrate for installing the germination test in beans depends on the type of product and active ingredient of the seed treatment. Emphasizing the substrates germitest® + vermiculite and germitest®+soil, those that best performed positive characteristics when in contact with the chemical treatment.

O uso de sementes de qualidade é um elemento chave para o sucesso dos cultivos do feijão carioca (Phaseolus vulgaris L.). Por ser uma forma de evitar ou reduzir problemas diversos de importância para a cultura, facilita a obtenção do potencial produtivo da cultivar e a redução de custos de produção. Tendo assim, como objetivo esse trabalho identificar quais as condições adequadas para avaliação da germinação em sementes de feijão através da utilização de diferentes substratos. Os tratamentos foram submetidos a temperatura de 25°C analisando cinco substratos (papel germitest®; papel germitest® + areia; papel germitest® +solo; papel germitest®+ carvão e papel germitest® + vermiculita). Os produtos químicos utilizados foram: Cruiser 350 FS, Fortenza 600 FS, Standak Top e Avicta completo. O substrato mais indicado para instalação do teste de germinação em feijão depende do tipo de produto e ingrediente ativo do tratamento de sementes. Destacando os substratos germitest® + vermiculita e germitest®+solo, os que melhor desempenharam características positivas quando em contato com o tratamento químico.

Growth analysis, photosynthate partition and nodulation in bean and soybean / Análise de crescimento, partição de fotoassimilados e nodulação em feijão e soja

Photoassimilate partition and allocation among plant organs varies throughout their development and is also influenced by factors inherent to the genotype and the environment. Nodulation in the soybean-diazotrophic bacteria interaction is more effective than in the bean-diazotrophic bacteria interaction. This investigation studied growth and photoassimilate partitioning throughout the bean and soybean cycles and inferred how much it could affect the nodulation of the roots. For this purpose, an experiment with two treatments was carried out, soybean (cultivar BRS GO - 7760 - RR) and bean (cultivar BRS Estilo), with four replications, conducted in pots and entirely randomized. The seeds were inoculated with commercial rhizobia specific for bean and soybean LeguMax® (Novozymes-Turfal). Plants were analyzed throughout their cycles based on leaf area and dry mass of all organs, including nodules. Mathematical models were fitted to the data and based on them, the instantaneous physiological indicators of growth were estimated, and the percentages of photoassimilate partition among organs were evaluated. Crop growth rate, relative growth rates, net assimilation rate as well as net photosynthesis rate had higher values in soybean compared to bean, following the pattern of leaf area and total dry mass. For both species, the highest rates occurred at the beginning of the cycle, decreasing with age. Unlike the bean, soybean has a high capacity to supply photosynthates to all of its organs throughout its entire cycle, favoring the maintenance of nodule growth and explaining its greater capacity for nitrogen assimilation.

Durante o desenvolvimento das plantas a partição e alocação de fotoassimilados variam entre os seus órgãos, e dependem de fatores inerentes ao genótipo e ao meio ambiente. A nodulação é mais efetiva na interação soja-bactéria diazotrófica do que na interação feijão-bactéria diazotrófica. Esta pesquisa tem como objetivo estudar o crescimento e a partição de fotoassimilados ao longo dos ciclos do feijão e da soja e inferir o quanto isso pode afetar a nodulação das raízes. Para tanto, foi instalado um experimento com dois tratamentos, soja (cultivar BRS GO - 7760 - RR) e feijão comum (cultivar BRS Estilo), com quatro repetições, conduzido em vasos e inteiramente ao acaso. As sementes foram inoculadas com inoculantes comerciais específicos para feijão e soja LeguMax® (Novozymes-Turfal). Plantas foram coletadas ao longo de seus ciclos e medidas as áreas foliares e as massas secas de todos os órgãos, incluindo nódulos. Modelos matemáticos foram ajustados aos dados e, com base neles, foram estimados os indicadores fisiológicos instantâneos do crescimento e, também, foram avaliadas as porcentagens de partição de fotoassimilados entre os órgãos. A taxa de crescimento das culturas (CGR), as taxas de crescimento relativo (RGR), a taxa líquida de assimilação (NAR) e a taxa líquida de fotossíntese (Pn) apresentaram maiores valores na soja em relação ao feijoeiro. Para ambas as culturas as maiores taxas ocorreram no início do ciclo, decrescendo ao longo do ciclo cultural. Diferentemente do feijoeiro a soja tem alta capacidade de suprir de fotoassimilados a todos os seus órgãos ao longo de todo o seu ciclo, o que favorece o maior crescimento dos seus nódulos, justificando a sua maior capacidade na captura do N2 atmosférico.

Agroeconomic response of inoculated common bean as affected by nitrogen application along the growth cycle / Resposta agroeconômica do feijão-comum inoculado em função da aplicação de nitrogênio ao longo do ciclo de crescimento

Biological nitrogen fixation (BNF) is an alternative for the supply of N, aiming at reducing production costs and environmental impacts of common bean crops. This work aimed to evaluate the agroeconomic performance of the inoculated common bean subjected to N-fertilizer application at different phenological phases. N-fertilizer, in a total of 90 kg ha-1 as urea, was applied at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were: P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. Inoculated treatment (P0V40R50) showed higher NN and NDM. Although inoculated treatment (P0V40R50) showed lower values of LAI, RDM, SDM, and GY, inoculation can result in GR, NR, and BCR equal to N-fertilized treatments, depending on the prices achieved for grains sale.

A fixação biológica de nitrogênio (FBN) é uma alternativa para o fornecimento de N, visando reduzir os custos de produção e os impactos ambientais da cultura do feijoeiro. Este trabalho teve como objetivo avaliar o desempenho agroeconômico do feijão inoculado submetido à aplicação de N-fertilizante em diferentes fases fenológicas. O fertilizante N, em um total de 90 kg ha-1 na forma de ureia, foi aplicado em 3 fases: plantio (P), fase fenológica V4 (V4) e fase fenológica R5 (R5) do feijoeiro, em dois experimentos de campo. Os tratamentos utilizados foram: P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530 e P90V40R50. Todos os tratamentos foram inoculados com inóculo de turfa contendo a cepa comercial SEMIA 4077 (Rhizobium tropici). O número de nódulos (NN), massa seca do nódulo (NDM), índice de área foliar (IAF), massa seca da raiz (RDM), massa seca da parte aérea (SDM), rendimento de grãos (GY), custo de produção (PC), receita bruta (GR), receita líquida (RL) e relação custo-benefício (BCR) foram apurados. O tratamento inoculado (P0V40R50) apresentou maior NN e NDM. Embora o tratamento inoculado (P0V40R50) tenha apresentado menores valores de LAI, RDM, SDM e GY, a inoculação pode resultar em GR, NR e BCR semelhantes aos tratamentos fertilizados com N, dependendo dos preços obtidos para a venda dos grãos.

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Water deficit on the physiological, morphoagronomic, and technological traits of carioca common bean genotypes

Water deficit can alter the morphological, agronomic, physiological, and technological traits of the common bean plant, affecting bean grain yield. In addition to yield aspects, the grain post-harvest quality is a decisive factor for the adoption of a new cultivar. Thus, this study evaluated the effect of water deficit on the physiological, morphoagronomic, and technological traits of common bean. The experiment was carried out at in a greenhouse in a randomized block design with a 30 × 2 factorial arrangement, consisting of 30 carioca common bean genotypes and two water regimes (with and without water stress), with three replications. The water deficit affected most morphological, agronomic, and physiological traits; however, it was not significant on the darkening of the seed coat. Cultivars IAC 1849 Polaco, ANFc 5, ANFc 9, BRSMG Madrepérola, IAC Carioca Aruã, TAA Dama, and Branquinho exhibited high yield potential under water stress treatment as well as slow seed coat darkening during nine months of storage. The selection of bean genotypes with slow seed coat darkening could be performed at 30 days of storage.

Combining disease resistance and postharvest quality traits by early marker-assisted backcrossing in carioca beans

ABSTRACT: Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC1F1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC1F1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC2F3) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time. The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Mobilization of seed storage proteins is crucial to high vigor in common bean seeds / Mobilização das proteínas de reserva é crucial para o alto vigor em sementes de feijão

Seed germination is a complex process controlled by many factors, in which physical and biochemical mechanisms are involved and the mobilization of reserves is crucial for this process to occur. Although, seed reserve mobilization is usually thought to be a post-germination process, seed reserve proteins mobilization occurs during germination. This study quantified seed proteins of bean genotypes during different hydration times, in order to understand the process of protein mobilization and whether there is relationship of this biochemical component with seed vigor. This study was conducted using seeds with different levels of vigor, genotypes with highest (13, 42, 55 and 81) and lowest (07, 23, 44, 50, IPR-88-Uirapurú and Iapar 81) physiological quality. High vigor genotypes showed greater efficiency in hydrolysis and mobilization of protein component, because they presented low globulins content in cotyledons at radicle protrusion in relation to low vigor genotypes (07, 23 and 50). The protein alpha-amylase inhibitor, observed in all genotypes, is involved with the longer time needed for radicle protrusion, according to the band intensity difference in genotypes 07, 44 and Iapar 81.

A germinação de sementes é um processo complexo controlado por muitos fatores, nos quais mecanismos físicos e bioquímicos estão envolvidos e a mobilização de reservas é decisiva para que esse processo ocorra. Embora a mobilização de reservas de sementes seja considerada um processo pós-germinativo, a mobilização das proteínas de reserva de sementes ocorre durante a germinação. Este estudo teve como objetivo quantificar as proteínas de sementes de genótipos de feijão durante os diferentes tempos de hidratação, a fim de compreender o processo de mobilização proteica e se há relação desse componente bioquímico com o vigor das sementes. Este estudo foi realizado utilizando sementes com diferentes níveis de vigor, genótipos com maior (13, 42, 55 e 81) e menor (07, 23, 44, 50, IPR-88-Uirapurú e Iapar 81) qualidade fisiológica. Os genótipos de alto vigor apresentaram maior eficiência na hidrólise e mobilização do componente proteico, pois apresentaram baixo teor de globulinas nos cotilédones na protrusão radicular em relação aos genótipos de baixo vigor (07, 23 e 50). A proteína inibidora da alfa-amilase, observada em todos os genótipos, está envolvida com o maior tempo necessário para a protrusão da radícula, de acordo com a diferença de intensidade da banda nos genótipos 07, 44 e Iapar 81.