Irrigation Strategies with Controlled Water Deficit in Two Production Cycles of Cotton.

Water scarcity is one of the main abiotic factors that limit agricultural production. In this sense, the identification of genotypes tolerant to water deficit associated with irrigation management strategies is extremely important. In this context, the objective of this study was to evaluate the morphology, production, water consumption, and water use efficiency of colored fiber cotton genotypes submitted to irrigation strategies with a water deficit in the phenological phases. Two experiments were conducted in succession. In the first experiment, a randomized block design was used in a 3 × 7 factorial scheme, corresponding to three colored cotton genotypes (BRS Rubi, BRS Jade, and BRS Safira) in seven irrigation management strategies with 40% of the real evapotranspiration (ETr) varying the phenological stages. In the second experiment, the same design was used in a 3 × 10 factorial arrangement (genotypes × irrigation management strategies). The water deficit in the vegetative phase can be used in the first year of cotton cultivation. Among the genotypes, 'BRS Jade' is the most tolerant to water deficit in terms of phytomass accumulation and fiber production.

Inoculation with Azospirillum argentinense Az19 improves the yield of maize subjected to water deficit at key stages of plant development.

Water deficit constitutes a severe limitation to agricultural productivity. In the context of sustainable crop production, the potential of microbial biotechnology to increase plant drought tolerance and improve crop yields under adverse conditions is gaining relevance. This work aimed to compare the performance of Azospirillumargentinense strain Az19 to that of strain Az39, the most widely used for commercial inoculants, when inoculated in maize plants exposed to water deficit. For this purpose, greenhouse and field assays were conducted. In the greenhouse experiment, strain Az19 prevented the adverse effect of water deficit at V2 stage on maize growth. Moreover, the percentage of fertile plants and the ear weight decreased significantly under water deficits imposed at V2 and flowering in Az39-inoculated plants but not in Az19-inoculated plants. In the first field trial with the commercial maize hybrid DOW DS 515 PW, Az19-inoculated plants were those which better tolerated the water deficit imposed. In the second field trial, two maize genotypes with differential drought sensitivity (LP 29×LP 2542, sensitive; LP 882 (923)×LP 4703, tolerant) were tested. Higher tolerance to water deficit was detected in plants inoculated with A. argentinense Az19, with a noticeable effect on grain yield components in the sensitive genotype. Based on these results, we propose the use of A. argentinense Az19 for the formulation of more targeted Azospirillum-based inoculants, suitable for agroecological areas subjected to seasonal water deficits.

Foliar cytokinins or brassinosteroids applications influence the rice plant acclimatization to combined heat stress.

The effect of different foliar sprays numbers of cytokinins - (CK) and brassinosteroids - (BR) on the physiological, biochemical, and panicle parameters of rice plants subjected to combined heat stress (high day/night temperatures) were studied in three different experiments. The treatments established for the first (E1) and second (E2) experiments were the following: i) absolute control, ii) stress control, iii) heat stress + one foliar spray of CK, iv) heat stress + two foliar sprays of CK, v) heat stress + three foliar sprays of CK, vi) heat stress + one foliar spray of BR, vii) heat stress + two foliar sprays of BR, or viii) heat stress + three foliar sprays of BR. For the third experiment (E3), the treatments were the following: i) absolute control, ii) stress control, iii) heat stress + three foliar applications of CK, iv) heat stress + three foliar applications of BR. Rice-stressed plants and sprayed with three foliar sprays of CK or BR had a better stomatal conductance in E1 and E2 compared to their heat-stressed control. The relative tolerance index suggests that three CK or BR applications helped to mitigate the combined heat stress in both experiments. The foliar CK or BR applications at the flowering and grain-filling stages in rice-stressed plants increased Fv/Fm ratio and panicle characteristics (number of filled spikelets and the percentage of panicle blanking in E3). In conclusion, foliar applications of BR or CK can be considered an agronomic strategy to help improve the negative effect of combined heat stress conditions on the physiological behavior of rice plants during different phenological stages.

Does doses and time of 2, 4-D application interfere in the physiology and wheat grains yield components?

The identification of the application stage and correct dose of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide is important so that wheat is not harmed. In view of this, the objective of this study was to evaluate the effect of 2,4-D doses applied at different development stages of wheat crop. The experiment was conducted in a randomized block design, arranged in a 4 × 5 factorial scheme, with four replications. In factor A, the application stages (before tillering, tillering, first node and booting) were allocated and the doses of 2,4-D (0, 349, 698, 1047 and 1396 g.ha­1) were allocated in factor B. The variables evaluated were phytotoxicity at 7, 14, 21, 28 and 35 days after application of the treatments (DAT), photosynthetic activity, CO2 internal concentration, stomatal conductance, efficient water use and carboxylation efficiency. The number of spikes·m­2, spike length and number of full and sterile grains were determined in the preharvest. Thousand grain mass, grain yield and hectoliter weight were determined after harvest. The results demonstrate that the herbicide caused phytotoxicity to wheat, being greater in increasing doses and mainly before tillering, causing grain sterility and decreased productivity. The other yield components did not present difference when increasing the dose and application in different stages as well as the physiological variables. The increase of the 2,4-D doses applied before tillering and in the booting stage caused linear decrease in wheat grain yield.

Root colonization and arbuscular mycorrhizal fungal community composition in a genetically modified maize, its non-modified isoline, and a landrace.

The use of genetically modified (GM) plants has increased in recent decades, but there are uncertainties about their effects on soil microbial communities. Aiming to quantify root colonization and characterize arbuscular mycorrhizal fungi (AMF) communities associated with roots and rhizosphere soil of different maize genotypes, a field trial was carried out in Southern Brazil with three maize genotypes as follows: a GM hybrid (DKB 240 VTPRO), its non-modified isoline (DKB 240), and a landrace (Pixurum). Soil samples were collected to evaluate the occurrence of AMF during the growth of corn genotypes at sowing and V3 (vegetative), R1 (flowering), and R3 (grain formation) stages of the crop. The occurrence of AMF was determined by the morphological identification of spores, and by analyzing AMF community composition in soil and roots of maize, using PCR-DGGE. The GM genotype of maize promoted lower mycorrhizal colonization in the vegetative stage and had lower sporulation at grain development than the conventional hybrid and the landrace maize. Twenty AMF morphotypes were identified and 13 were associated with all maize genotypes. The genera Acaulospora, Glomus, and Dentiscutata had the largest numbers of species. There were no differences in AMF community composition due to maize genotypes or genetic modification, but crop phenological stages affected AMF communities associated with maize roots.

Corn hybrid silage quality according to harvesting time / Qualidade da silagem de híbridos de milho em função do ponto de colheita

The present study aimed to evaluate the dry matter production of different corn hybrids, the plant chemical composition at the time of ensiling and the participation of the structural components of the plant at the different phenological stages. Corn hybrids P2530, P30B39H and P30R50H were harvested successively at the kernel blister (R2); kernel milk (R3); kernel dough (R4); and kernel dent (R5) stages. We determined the dry matter contents, the percentage participation of each physical structure of the plant at the time of each evaluation, as well as the first ear height, plant height, number of dry leaves, production of dry ensilable phytomass, grain and chemical composition at the time of ensiling (kernel dent stage, R5). There was no difference (p > 0.05) in dry phytomass production between the evaluated hybrids. In general, the hybrid P30R50H, considering dry biomass production and fiber composition of the plant and relative value of the food was balanced for silage. The advance of the stages provided an increase in the grain participation and consequent reduction of the other components in the physical composition of the plant, and the R4 stage was the moment of best association between productivity and physical composition of the plant for silage production.(AU)

O objetivo do trabalho foi avaliar a produção de matéria seca de diferentes híbridos de milho, a bromatologia da planta no momento da ensilagem bem como a participação dos componentes estruturais da planta nos diferentes estádios fenológicos. Foram utilizados os híbridos de milho P2530, P30B39H e P30R50H, colhidos sucessivamente nas fases de grão leitoso(R2); grão pastoso(R3); grão farináceo(R4); e grão farináceo-duro (R5). Determinou-se os teores de matéria seca, a participação percentual de cada estrutura física da planta, na ocasião de cada avaliação, além da altura da inserção da primeira espiga e da planta, número de folhas secas, produção de fitomassa seca ensilável, de grãos e bromatologia no momento da ensilagem (fase de grão farináceo-duro, R5). Não houve diferença (p > 0,05) na produção de fitomassa seca entre os híbridos avaliados. Em geral o híbrido P30R50H, considerando a produção de biomassa seca e composição fibrosa da planta e valor relativo do alimento mostrou-se equilibrado para silagem. O avanço dos estádios proporcionou aumento na participação de grãos e consequente redução dos demais componentes na composição física da planta, e o estádio R4 apresentou-se como o momento de melhor associação entre produtividade e composição física da planta para produção de silagem.(AU)

Corn hybrid silage quality according to harvesting time / Qualidade da silagem de híbridos de milho em função do ponto de colheita

The present study aimed to evaluate the dry matter production of different corn hybrids, the plant chemical composition at the time of ensiling and the participation of the structural components of the plant at the different phenological stages. Corn hybrids P2530, P30B39H and P30R50H were harvested successively at the kernel blister (R2); kernel milk (R3); kernel dough (R4); and kernel dent (R5) stages. We determined the dry matter contents, the percentage participation of each physical structure of the plant at the time of each evaluation, as well as the first ear height, plant height, number of dry leaves, production of dry ensilable phytomass, grain and chemical composition at the time of ensiling (kernel dent stage, R5). There was no difference (p > 0.05) in dry phytomass production between the evaluated hybrids. In general, the hybrid P30R50H, considering dry biomass production and fiber composition of the plant and relative value of the food was balanced for silage. The advance of the stages provided an increase in the grain participation and consequent reduction of the other components in the physical composition of the plant, and the R4 stage was the moment of best association between productivity and physical composition of the plant for silage production.

O objetivo do trabalho foi avaliar a produção de matéria seca de diferentes híbridos de milho, a bromatologia da planta no momento da ensilagem bem como a participação dos componentes estruturais da planta nos diferentes estádios fenológicos. Foram utilizados os híbridos de milho P2530, P30B39H e P30R50H, colhidos sucessivamente nas fases de grão leitoso(R2); grão pastoso(R3); grão farináceo(R4); e grão farináceo-duro (R5). Determinou-se os teores de matéria seca, a participação percentual de cada estrutura física da planta, na ocasião de cada avaliação, além da altura da inserção da primeira espiga e da planta, número de folhas secas, produção de fitomassa seca ensilável, de grãos e bromatologia no momento da ensilagem (fase de grão farináceo-duro, R5). Não houve diferença (p > 0,05) na produção de fitomassa seca entre os híbridos avaliados. Em geral o híbrido P30R50H, considerando a produção de biomassa seca e composição fibrosa da planta e valor relativo do alimento mostrou-se equilibrado para silagem. O avanço dos estádios proporcionou aumento na participação de grãos e consequente redução dos demais componentes na composição física da planta, e o estádio R4 apresentou-se como o momento de melhor associação entre produtividade e composição física da planta para produção de silagem.

Evaluation of Rhizobia strains UFLA 02 100 and CIAT 899 in line LEP 02 11 of Phaseolus vulgaris L / Avaliação das estirpes de rizóbio ufla 02 100 e cia t 899 na linhagem lep 02 11 de phaseolus vulgaris l

The growing quest for sustainability in agricultural production systems has been pushing researchers to develop new technologies under different soil and climatic conditions. Based on this, and knowing the socioeconomic importance of the bean, the use of biological nitrogen fixation (BNF) is explored. Thus, the quest for quantitative knowledge of BNF at the phenological stages in a new bean line using promising and commercial strains becomes necessary. The objective of this study was to evaluate the strains UFLA 02 100 and CIAT 899 in the different phenological stages of the LEP 02 11 common bean strain using the biological nitrogen fixation. The experiment was conducted in a greenhouse on the Maringá-PR campus of the State University of Maringá. The design was a randomized complete block design in a 6x4 factorial scheme with four replications. The factor A comprised six nitrogen sources: Control, strain UFLA 02 100, strain CIAT 899, Nitrogen 60 kg ha-1, strain UFLA 02 100 + Nitrogen 30 kg ha-1, strain CIAT 899 + Nitrogen 30 kg ha-1 and the B factor is the phenological stages V4, R5, R6 and R8. The analyzed variables were: dry mass of nodules (DMN, grams/plant), dry mass of shoot (DMS, grams/plant), nitrogen content in shoot (NCS, %) and accumulation of nitrogen in shoot (ANS, grams/plant). For the statistical analysis of the data, the means test was used for the variables in the stages. The CIAT 899 strain statistically outperformed UFLA 02 100 for most variables and it was found that nitrogen fertilization negatively affected nodulation

A crescente busca pela sustentabilidade nos sistemas de produção agrícolas vem impulsionando os pesquisadores a desenvolverem novas tecnologias nas diferentes condições edafoclimáticas. Com base nisso, e sabendo da importância socioeconômica do feijoeiro, o uso da fixação biológica de nitrogênio (FBN) é explorada. Assim, a busca do conhecimento quantitativo da FBN nos estádios fenológicos em uma nova linhagem de feijão utilizando estirpes promissoras e comerciais se torna necessário. Destamaneira, o objetivo foi avaliar as estirpes UFLA 02 100 eCIAT 899nos diferentes estádios fenológicos da linhagem de feijão comum LEP 02 11 mediante o uso da fixação biológica de nitrogênio. O experimento foi conduzido em casa de vegetaçãono campus de Maringá-PR da Universidade Estadual de Maringá. O delineamento foi o de blocos ao acaso (DBC) em esquema fatorial 6x4 com quatro repetições. O fator A compreendeu seis fontes de nitrogênio: Testemunha, estirpe UFLA 02 100, estirpe CIAT 899, Nitrogênio 60 kg ha-1, estirpe UFLA 02 100+Nitrogênio 30 kg ha-1, estirpe CIAT 899+Nitrogênio 30 kg ha-1 e o fator B os estádios fenológicos V4, R5, R6 e R8. As variáveis analisadas foram: massa seca de nódulos (MSN, gramas/planta), massa seca da parte aérea (MSPA, gramas/planta), teor de nitrogênio na parte aérea (TNPA, %) e acúmulo de nitrogênio na parte aérea (ANPA, gramas/planta). Para a análise estatística dos dados utilizou-se o teste de médias para as variáveis nos estádios. A estirpe CIAT 899 superou estatisticamente a UFLA 02 100 para a maioria das variáveis e constatou-se que a adubação nitrogenada afetou negativamente a nodulação.

Effect of herbage allowances on biomass flows in Italian ryegrass / Efeito de ofertas de forragem sobre o fluxo de biomassa em azevém

The objective of this study was to determine the leaf tissue flows in Italian ryegrass (Lolium multiflorum Lam.), in different phenological stages, grazed by lambs, and managed under three herbage allowances (6, 9 and 12 kg DM/100 kg body weight under rotational stocking method. The experimental design was completely randomized, with repeated measures arrangement. Forage allowances determined similar growth and intake flows, actual and potential utilization efficiencies of grass and they were different in the phenological stages of Italian ryegrass. The intake of leaf blade, as a percentage of body weight, was higher in the 12% herbage allowance. Considering leaf tissue flows, Italian ryegrass can be managed in forage allowances that vary between 6 and 12 kg DM/100 kg body weight.(AU)

Este trabalho foi conduzido com o objetivo de determinar os fluxos de tecidos foliares em diferentes estádios fenológicos do azevém (Lolium multiflorum Lam.), pastejado por cordeiras, manejado sob três níveis de oferta de forragem (6; 9 e 12 kg de MS/100 kg de peso corporal), sob lotação intermitente. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo. Os fluxos de crescimento e consumo de lâminas foliares, as eficiências real e potencial de utilização do pasto foram similares nas ofertas de forragem e diferentes nos estádios fenológicos do azevém. O consumo de lâminas foliares em porcentagem do peso corporal foi superior na oferta de forragem 12%. Considerando os fluxos de tecidos foliares, o azevém pode ser manejado com ofertas de forragem que variam entre 6 a 12 kg de MS/100 kg de peso corporal.(AU)

Effect of herbage allowances on biomass flows in Italian ryegrass / Efeito de ofertas de forragem sobre o fluxo de biomassa em azevém

ABSTRACT: The objective of this study was to determine the leaf tissue flows in Italian ryegrass (Lolium multiflorum Lam.), in different phenological stages, grazed by lambs, and managed under three herbage allowances (6, 9 and 12 kg DM/100 kg body weight under rotational stocking method. The experimental design was completely randomized, with repeated measures arrangement. Forage allowances determined similar growth and intake flows, actual and potential utilization efficiencies of grass and they were different in the phenological stages of Italian ryegrass. The intake of leaf blade, as a percentage of body weight, was higher in the 12% herbage allowance. Considering leaf tissue flows, Italian ryegrass can be managed in forage allowances that vary between 6 and 12 kg DM/100 kg body weight.

RESUMO: Este trabalho foi conduzido com o objetivo de determinar os fluxos de tecidos foliares em diferentes estádios fenológicos do azevém (Lolium multiflorum Lam.), pastejado por cordeiras, manejado sob três níveis de oferta de forragem (6; 9 e 12 kg de MS/100 kg de peso corporal), sob lotação intermitente. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo. Os fluxos de crescimento e consumo de lâminas foliares, as eficiências real e potencial de utilização do pasto foram similares nas ofertas de forragem e diferentes nos estádios fenológicos do azevém. O consumo de lâminas foliares em porcentagem do peso corporal foi superior na oferta de forragem 12%. Considerando os fluxos de tecidos foliares, o azevém pode ser manejado com ofertas de forragem que variam entre 6 a 12 kg de MS/100 kg de peso corporal.

Caracterización del subsistema de plagas en mora sin espina (rubus glaucus benth) en el departamento de Risaralda / Characterization of the subsystem pests of the thornless blackberry (rubus glaucus benth) in the department of Risaralda

Objetivo. Por medio del modelo de taller participativo se realizó la caracterización del subsistema de plagas de mora sin espina en el departamento de Risaralda con agricultores de las diferentes asociaciones. Metodología. Se utilizó el análisis multivariado, empleando la técnica de correspondencias múltiples para variables categóricas a fin de hallar los clústers de productores; posteriormente, una prueba Chi-cuadrado comparó los resultados de cada clúster y verificó las diferencias significativas que podían existir dentro de los mismos. Resultados y conclusión. Con base en la presencia de insectos por cada etapa fenológica del cultivo se encontraron cinco clústers de agricultores. Los moricultores del departamento reportaron como organismos presentes en el sistema productivo insectos de las familias Thripidae, Chrysomelidae, Melolonthidae y Aphididae, y de las especies Atta sp., Hepialus sp., Monalonion sp., Prodiplosis sp., Eurhizococcus colombianus, y moluscos como babosas (Orden: Pulmonata); sin embargo, los trips y el barrenador de tallo (Hepialus sp.) fueron los insectos fitófagos más prevalentes. Asimismo, una prueba Chi-cuadrado determinó que, según la percepción del agricultor, los trips son los insectos más prevalentes durante todas las etapas fenológicas del cultivo.

Objective: Using the participatory workshop model, the characterization of the non-thorn blackberry subsystem pests was carried out in the Department of Risaralda with farmers from the different associations. Methodology: Multivariate analysis was used, using the multiple correspondence technique for categorical variables to find producer clusters. Subsequently, a Chi-square test compared the results of each cluster and verified the significant differences that could exist within them. Results and conclusion: Based on the presence of insects for each phenological stage of the crop, five farmer clusters were found. Blackberry growers of the Department reported insects of the families Thripidae, Chrysomelidae, Melolonthidae and Aphididae, and of the species Atta sp., Hepialus sp., Monalonion sp., Prodiplosis sp.,, Eurhizococcus colombianus, and mollusks as slugs (Order: Pulmonata), as organisms present in the productive system. However, thrips and the stem borers (Hepialus sp.) were the most prevalent phytophagous insects. Likewise, a Chi-square test determined that, according to the farmer's perception, thrips are the most prevalent insects during all the phenological stages of the crop.

Qualidade fisiológica de sementes de soja submetidas à dessecação em pré-colheita / Physiological quality of soybean seeds submitted to pre-harvest desiccation

A utilização de sementes de soja (Glycine max L.) com alta qualidade é um dos aspectos diretamente responsáveis para a obtenção de índices satisfatórios de produtividade. A prática de dessecação é uma importante aliada dos produtores para antecipação da colheita e minimização da rápida deterioração da qualidade de sementes no campo. Neste contexto, o trabalho teve como objetivo avaliar o efeito do uso de dessecantes aplicados no estádio R7 sobre a qualidade fisiológica de sementes de soja. O experimento foi conduzido em área experimental, localizada no município de Passo Fundo, Rio Grande do Sul. Foram semeadas sob delineamento experimental parcela dividida, quatro cultivares de soja (FPS Jupiter RR, FPS Paranapanema RR, BRS Tordilha RR e FPS Urano RR), manejadas segundo recomendações técnicas para a cultura. Ao atingir o estádio R7 aplicou-se diferentes manejos de dessecação (sem dessecação, paraquat, diquat e glufosinato de amônio) na sub parcela. As sementes foram colhidas com colhedora de parcelas e avaliou-se o peso de mil sementes, a germinação e envelhecimento acelerado, sendo os dois últimos, avaliados aos 30 e 180 dias após a colheita. A dessecação em pré-colheita no estádio R7 da cultura da soja não afeta negativamente a qualidade fisiológica das sementes e, de modo geral, para as cultivares FPS Júpiter RR e FPS Urano RR, possibilitou a obtenção de sementes mais vigorosas aos 30 DAC. Nas condições em que o experimento foi conduzido, os herbicidas diquat, paraquat e glufosinato de amônio podem ser utilizados para dessecação em pré-colheita nos campos de produção de sementes.

The use of high quality soybean seeds (Glycine max L.) is one of the most important aspects to obtain satisfactory productivity indexes. The desiccation practice is an important idea of the producers to anticipate the harvest and to minimize the rapid deterioration of seed quality in the field. In this context, the objective of this work was to evaluate the effect of the use of desiccants applied in R7 stage on the physiological quality of soybean seeds. The experiment was conducted in experimental area, located in the city of Passo Fundo, Rio Grande do Sul. Four soybean cultivars (FPS Jupiter RR, FPS Paranapanema RR, BRS Tordilha RR and FPS Urano RR) were planted under experimental design, managed according to technical recommendations for the crop. Upon reaching the R7 stage, different desiccation treatments (without desiccation, paraquat, diquat and glufosinate ammonium) were applied to the subplot. The seeds were harvested with a plot harvester and the weight of one thousand seeds, germination test and accelerated aging test were evaluated, being the last two evaluated at 30 and 180 days after harvest. The pre-harvest desiccation at the R7 stage of soybean cultivation did not negatively affect the physiological quality of the seeds and, generally way, for the cultivars FPS Jupiter RR and FPS Urano RR, it was possible to obtain more vigorous seeds at 30 DAC. Under the conditions under which the experiment was conducted, the diquat, paraquat and glufosinate ammonium herbicides can be used for pre-harvest desiccation in the seed production fields.

Qualidade fisiológica de sementes de soja submetidas à dessecação em pré-colheita / Physiological quality of soybean seeds submitted to pre-harvest desiccation

A utilização de sementes de soja (Glycine max L.) com alta qualidade é um dos aspectos diretamente responsáveis para a obtenção de índices satisfatórios de produtividade. A prática de dessecação é uma importante aliada dos produtores para antecipação da colheita e minimização da rápida deterioração da qualidade de sementes no campo. Neste contexto, o trabalho teve como objetivo avaliar o efeito do uso de dessecantes aplicados no estádio R7 sobre a qualidade fisiológica de sementes de soja. O experimento foi conduzido em área experimental, localizada no município de Passo Fundo, Rio Grande do Sul. Foram semeadas sob delineamento experimental parcela dividida, quatro cultivares de soja (FPS Jupiter RR, FPS Paranapanema RR, BRS Tordilha RR e FPS Urano RR), manejadas segundo recomendações técnicas para a cultura. Ao atingir o estádio R7 aplicou-se diferentes manejos de dessecação (sem dessecação, paraquat, diquat e glufosinato de amônio) na sub parcela. As sementes foram colhidas com colhedora de parcelas e avaliou-se o peso de mil sementes, a germinação e envelhecimento acelerado, sendo os dois últimos, avaliados aos 30 e 180 dias após a colheita. A dessecação em pré-colheita no estádio R7 da cultura da soja não afeta negativamente a qualidade fisiológica das sementes e, de modo geral, para as cultivares FPS Júpiter RR e FPS Urano RR, possibilitou a obtenção de sementes mais vigorosas aos 30 DAC. Nas condições em que o experimento foi conduzido, os herbicidas diquat, paraquat e glufosinato de amônio podem ser utilizados para dessecação em pré-colheita nos campos de produção de sementes.(AU)

The use of high quality soybean seeds (Glycine max L.) is one of the most important aspects to obtain satisfactory productivity indexes. The desiccation practice is an important idea of the producers to anticipate the harvest and to minimize the rapid deterioration of seed quality in the field. In this context, the objective of this work was to evaluate the effect of the use of desiccants applied in R7 stage on the physiological quality of soybean seeds. The experiment was conducted in experimental area, located in the city of Passo Fundo, Rio Grande do Sul. Four soybean cultivars (FPS Jupiter RR, FPS Paranapanema RR, BRS Tordilha RR and FPS Urano RR) were planted under experimental design, managed according to technical recommendations for the crop. Upon reaching the R7 stage, different desiccation treatments (without desiccation, paraquat, diquat and glufosinate ammonium) were applied to the subplot. The seeds were harvested with a plot harvester and the weight of one thousand seeds, germination test and accelerated aging test were evaluated, being the last two evaluated at 30 and 180 days after harvest. The pre-harvest desiccation at the R7 stage of soybean cultivation did not negatively affect the physiological quality of the seeds and, generally way, for the cultivars FPS Jupiter RR and FPS Urano RR, it was possible to obtain more vigorous seeds at 30 DAC. Under the conditions under which the experiment was conducted, the diquat, paraquat and glufosinate ammonium herbicides can be used for pre-harvest desiccation in the seed production fields.(AU)

Yield, structural composition and nutritive characteristics of ryegrass cultivars used to haymaking in lowland soils / Rendimento, composição estrutural e características nutritivas de cultivares de azevém utilizadas para fenação em solos de várzea

This research aimed to evaluate the dry matter yield, structural composition and nutritive characteristics of diploid and tetraploid annual ryegrass cultivars on different phenological development to haymaking on lowland soils. The experimental design was developed based on randomized blocks with split plots, four cultivars of annual ryegrass (BRS Ponteio and FEPAGRO São Gabriel, diploid; INIA Escorpio and KLM 138, tetraploid), and three phenological crop phases (vegetative, pre-blossoming and blossoming). Were evaluated, dry matter yield, leaf:stem ratio, leaf weight ratio, tiller population density, specific leaf area, crude protein, neutral detergent fiber, and acid detergent fiber. All data were submitted to analysis of variance and the means were compared by Tukey-Kramer test (p< 0,05). Highest forage mass is obtained with harvest in blossoming stage. Tetraploid cultivars present better leaf proportion and higher content of crude protein during vegetative stage. The decrease the in concentration of protein with the change of phenological stage is less evident on diploid cultivars. The vegetative stage enables harvest forage with high nutritional value, with lower production of biomass.

O objetivo do trabalho foi avaliar o rendimento de matéria seca, composição estrutural e características nutritivas de cultivares de azevém anual, diploides e tetraploides em diferentes estádios fenológicos, para fenação, em solos de várzea. O delineamento experimental foi de blocos ao acaso, com parcelas divididas, com quatro cultivares de azevém anual (BRS Ponteio e FEPAGRO São Gabriel, diploides; INIA Escorpio e KLM 138, tetraploides) e três estádios fenológicos (vegetativo, pré-florescimento e florescimento). Foram avaliadas: rendimento de matéria seca, relação folha/colmo, razão de peso foliar, densidade populacional de perfilhos, área foliar específica, proteína bruta, fibra em detergente neutro e fibra em detergente ácido. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Tukey-Kramer (p <0,05). A maior massa de forragem é obtida com a colheita no estádio de florescimento. As cultivares tetraploides apresentam melhor proporção foliar e maior teor de proteína bruta durante o período vegetativo. A diminuição na concentração de proteína, com a mudança de estádio fenológico é menos evidente nas cultivares diploides. O estágio vegetativo possibilita a colheita de forragem com alto valor nutricional, mas com menor produção de biomassa.

Leaf area index and SPAD during the soybean development cycle at different plant densities and their relation to grain yield / Índice de área foliar e SPAD durante o ciclo da soja em função da densidade de plantas e sua relação com a produtividade de grãos

Sowing density in the soybean crop promotes several morphophysiological changes in the plants, which can alter plant growth and grain yield. The objective of this study was to evaluate the effect of soybean plant densities on the leaf area index (LAI) and Soil Plant Analysis Development (SPAD) index during the soybean crop development cycle and correlating these data with grain yield. The experiment was conducted in the experimental area of Embrapa Soja, Londrina, Paraná State, Brazil, under a randomized complete block design, with five replications. The densities of 120, 230, 340 and 380 thousand viable plants ha-1 were evaluated in row spacing of 0.45 m using the BRS 359 RR cultivar, which has indeterminate growth type and compact architecture. The increased plant density promotes an increment in LAI from the V4 stage to R3; however, after this stage, LAI is similar among densities. Plant density did not change the SPAD index before R5.4. During the vegetative growth there is no correlation between LAI and SPAD and grain yield, but in the grain filling period there are positive correlations between these variables.

A densidade de semeadura na cultura da soja provoca diversas modificações morfofisiológicas nas plantas, podendo alterar o crescimento e a produtividade de grãos. Objetivou-se avaliar o efeito de densidades de plantas de soja sobre o índice de área foliar (IAF) e índice SPAD (Soil Plant Analysis Development) durante o ciclo de desenvolvimento da cultura, correlacionando esses dados com a produtividade de grãos. O experimento foi conduzido na safra 2015/16, na área experimental da Embrapa Soja, Londrina, PR, em delineamento experimental de blocos completos casualizados, com cinco repetições. Foram avaliadas as densidades de 120, 230, 340 e 380 mil plantas aptas ha-1, em espaçamento de 0,45 m entre fileiras, utilizando a cultivar BRS 359 RR, que apresenta tipo de crescimento indeterminado e arquitetura compacta de plantas. Constatou-se que o aumento da densidade de plantas de soja incrementa o IAF até o estádio R3, mas, após essa fase, o IAF não varia entre as densidades. A densidade de plantas de soja não altera o índice SPAD até o estádio R5.4. Durante o crescimento vegetativo não há correlação entre o IAF e o índice SPAD com a produtividade de grãos, porém na fase de enchimento de grãos há correlações positivas entre essas variáveis.

Leaf area index and SPAD during the soybean development cycle at different plant densities and their relation to grain yield / Índice de área foliar e SPAD durante o ciclo da soja em função da densidade de plantas e sua relação com a produtividade de grãos

Sowing density in the soybean crop promotes several morphophysiological changes in the plants, which can alter plant growth and grain yield. The objective of this study was to evaluate the effect of soybean plant densities on the leaf area index (LAI) and Soil Plant Analysis Development (SPAD) index during the soybean crop development cycle and correlating these data with grain yield. The experiment was conducted in the experimental area of Embrapa Soja, Londrina, Paraná State, Brazil, under a randomized complete block design, with five replications. The densities of 120, 230, 340 and 380 thousand viable plants ha-1 were evaluated in row spacing of 0.45 m using the BRS 359 RR cultivar, which has indeterminate growth type and compact architecture. The increased plant density promotes an increment in LAI from the V4 stage to R3; however, after this stage, LAI is similar among densities. Plant density did not change the SPAD index before R5.4. During the vegetative growth there is no correlation between LAI and SPAD and grain yield, but in the grain filling period there are positive correlations between these variables.(AU)

A densidade de semeadura na cultura da soja provoca diversas modificações morfofisiológicas nas plantas, podendo alterar o crescimento e a produtividade de grãos. Objetivou-se avaliar o efeito de densidades de plantas de soja sobre o índice de área foliar (IAF) e índice SPAD (Soil Plant Analysis Development) durante o ciclo de desenvolvimento da cultura, correlacionando esses dados com a produtividade de grãos. O experimento foi conduzido na safra 2015/16, na área experimental da Embrapa Soja, Londrina, PR, em delineamento experimental de blocos completos casualizados, com cinco repetições. Foram avaliadas as densidades de 120, 230, 340 e 380 mil plantas aptas ha-1, em espaçamento de 0,45 m entre fileiras, utilizando a cultivar BRS 359 RR, que apresenta tipo de crescimento indeterminado e arquitetura compacta de plantas. Constatou-se que o aumento da densidade de plantas de soja incrementa o IAF até o estádio R3, mas, após essa fase, o IAF não varia entre as densidades. A densidade de plantas de soja não altera o índice SPAD até o estádio R5.4. Durante o crescimento vegetativo não há correlação entre o IAF e o índice SPAD com a produtividade de grãos, porém na fase de enchimento de grãos há correlações positivas entre essas variáveis.(AU)

Effect of supplementation frequency in feeding behavior, displacement patterns and forage intake of beef heifers / Efeito de frequências de suplementação no comportamento ingestivo, padrões de deslocamento e ingestão de forragem por novilhas de corte

Our work was carried out to evaluate forage intake, feeding behavior and displacement patterns of beef heifers fed exclusively on pasture or receiving oat grain, either daily (frequent) or from Monday to Friday (infrequent), in two phenological stages of Alexandergrass (Urochloa plantaginea Link.): Vegetative and Reproductive. The grazing method was continuous, with a variable number of animals. The experimental design was completely randomized with measures repeated in time with three feeding frequencies and two phenological stages. Forage intake was estimated using the chromic oxide technique as an indicator of fecal output. Heifers on exclusive Alexandergrass pasture and frequently supplemented had higher forage intake of dry matter (DM, 2.91 kg DM 100 kg BW-1) than those that were infrequently supplemented (2.00 kg DM 100 kg BW-1). Forage intake was greater in the Vegetative stage. The use of feeding stations is modified in response to supplementation frequency and phenological stages of Alexandergrass. Bite mass was higher for daily supplemented heifers, and these animals spent less time grazing. Also, bite mass was the item that best explained DM total ingestion. Bite mass and grazing time were similar throughout the phenological stages, whereas bite rate decreased in the reproductive stage. Feeding behavior and forage intake responses of beef heifers were influencedby supplementation frequency and phenological stages of Alexandergrass.(AU)

Nos estádios fenológicos Vegetativo e Reprodutivo do papuã (Urochloa plantaginea Link.) foram avaliados a ingestão de matéria seca, o comportamento ingestivo e os padrões de deslocamento de novilhas em pastejo ou recebendo grão de aveia diariamente (frequente) ou de segunda a sexta-feira (infrequente). O método de pastejo foi contínuo com número variável de animais. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo com três frequências alimentares e dois estádios fenológicos. A ingestão de matéria seca foi estimada por meio de técnica do óxido de cromo como indicador da produção fecal. Animais em pastagem exclusiva de papuã e com suplemento diário consumiram mais forragem (2,91 kg MS 100 kg PC-1) que os animais que receberam suplemento infrequente (2,00 kg MS 100 kg PC-1). O consumo de forragem foi maior no estádio Vegetativo do que no Reprodutivo. O uso das estações alimentares é modificado em resposta as frequências de suplementação e estádios fenológicos. Novilhas que receberam suplemento diariamente pastejaram por menor tempo e colheram bocados mais pesados. A massa de bocado é o item que melhor explica a ingestão total de MS. O peso do bocado e o tempo de pastejo foram semelhantes nos estádios fenológicos do pasto enquanto a taxa de bocado diminuiu no estádio reprodutivo. Mudanças na frequência de suplementação e nos estádios fenológicos do papuã modificam o comportamentoingestivo e o consumo de forragem de novilhas de corte.(AU)

Influence of host preference, mating, and release density on the parasitism of Telenomus remus (Nixon) (Hymenoptera, Platygastridae)

ABSTRACT We evaluated the influence of host preference, mating, and release density on Telenomus remus (Nixon, 1937) (Hymenoptera: Platygastridae) parasitizing eggs of Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). First, we tested host preference of T. remus (free choice test) offered a choice between eggs of Corcyra cephalonica (Stainton, 1865) (Lepidoptera: Pyralidae) and S. frugiperda. Parasitism capacity and host preference (S. frugiperda) of T. remus reared on either of the two hosts did not differ. Secondly, we evaluated the influence of mating behavior of T. remus females on its parasitism. Only the offspring sex ratio differed between treatments, indicating that the species reproduces by parthenogenesis of the arrhenotoky type. Finally, we evaluated the influence of release density on T. remus parasitism. This was tested by releasing different numbers of the parasitoid per S. frugiperda egg using T. remus reared for different numbers of generations on C. cephalonica eggs. The regression analysis between percentage of parasitism and density of released T. remus females showed a quadratic effect for all tested parasitoid generations (F35, F40, and F45) with maximum parasitism from 65.07% to 71.69%. Our results allow the conclusion that (a) T. remus prefers S. frugiperda eggs, regardless of the host on which this parasitoid was reared, showing no preimaginal conditioning; (b) Mating does not affect the number of eggs parasitized by T. remus or the development of its offspring; and (c) The optimal T. remus release density when reared on C. cephalonica is between 0.133 and 0.150 females/S. frugiperda.

Effect of supplementation frequency in feeding behavior, displacement patterns and forage intake of beef heifers / Efeito de frequências de suplementação no comportamento ingestivo, padrões de deslocamento e ingestão de forragem por novilhas de corte

Our work was carried out to evaluate forage intake, feeding behavior and displacement patterns of beef heifers fed exclusively on pasture or receiving oat grain, either daily (frequent) or from Monday to Friday (infrequent), in two phenological stages of Alexandergrass (Urochloa plantaginea Link.): Vegetative and Reproductive. The grazing method was continuous, with a variable number of animals. The experimental design was completely randomized with measures repeated in time with three feeding frequencies and two phenological stages. Forage intake was estimated using the chromic oxide technique as an indicator of fecal output. Heifers on exclusive Alexandergrass pasture and frequently supplemented had higher forage intake of dry matter (DM, 2.91 kg DM 100 kg BW-1) than those that were infrequently supplemented (2.00 kg DM 100 kg BW-1). Forage intake was greater in the Vegetative stage. The use of feeding stations is modified in response to supplementation frequency and phenological stages of Alexandergrass. Bite mass was higher for daily supplemented heifers, and these animals spent less time grazing. Also, bite mass was the item that best explained DM total ingestion. Bite mass and grazing time were similar throughout the phenological stages, whereas bite rate decreased in the reproductive stage. Feeding behavior and forage intake responses of beef heifers were influencedby supplementation frequency and phenological stages of Alexandergrass.

Nos estádios fenológicos Vegetativo e Reprodutivo do papuã (Urochloa plantaginea Link.) foram avaliados a ingestão de matéria seca, o comportamento ingestivo e os padrões de deslocamento de novilhas em pastejo ou recebendo grão de aveia diariamente (frequente) ou de segunda a sexta-feira (infrequente). O método de pastejo foi contínuo com número variável de animais. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo com três frequências alimentares e dois estádios fenológicos. A ingestão de matéria seca foi estimada por meio de técnica do óxido de cromo como indicador da produção fecal. Animais em pastagem exclusiva de papuã e com suplemento diário consumiram mais forragem (2,91 kg MS 100 kg PC-1) que os animais que receberam suplemento infrequente (2,00 kg MS 100 kg PC-1). O consumo de forragem foi maior no estádio Vegetativo do que no Reprodutivo. O uso das estações alimentares é modificado em resposta as frequências de suplementação e estádios fenológicos. Novilhas que receberam suplemento diariamente pastejaram por menor tempo e colheram bocados mais pesados. A massa de bocado é o item que melhor explica a ingestão total de MS. O peso do bocado e o tempo de pastejo foram semelhantes nos estádios fenológicos do pasto enquanto a taxa de bocado diminuiu no estádio reprodutivo. Mudanças na frequência de suplementação e nos estádios fenológicos do papuã modificam o comportamentoingestivo e o consumo de forragem de novilhas de corte.

Temporal variation of normalized difference vegetation index (NDVI) and calculation of the crop coefficient (Kc ) from NDVI in areas cultivated with irrigated soybean / Variação temporal do Índice de Vegetação por Diferença Normalizada (NDVI) e obtenção do coeficiente de cultura (Kc ) a partir do NDVI em áreas cultivadas com soja irrigada

ABSTRACT: Vegetation indices obtained by remote sensing products have various applications in agriculture. An important application of the Normalized Difference Vegetation Index (NDVI) is obtaining the crop coefficient (Kc). The aims of this study were to analyze NDVI temporal profiles and to obtain Kc from the NDVI vegetation index product MOD13Q1. The analysis is based on the phenological stages of irrigated soybean crops in the municipality of Planura/MG during the 2010/2011 growing season. Areas planted with irrigated soybean were identified through fieldwork. Temporal series of the MOD13Q1 products were used to analyze NDVI, allowing the extraction of NDVI values for all points in the period studied. The NDVI temporal profiles showed a similar pattern to each other and corresponded to the crop cycle. The KcNDVI values for the MOD13Q1 products were well correlated to the FAO Kc values (r2=0.72). Thus, NDVI can be used as an alternative for obtaining crop coefficient (Kc).

RESUMO: Os índices de vegetação obtidos a partir de produtos de sensoriamento remoto apresentam várias aplicações na agricultura. Uma importante aplicação do índice de vegetação Normalized Difference Vegetation Index (NDVI) está relacionada à obtenção do coeficiente de cultura (Kc). Assim, o objetivo deste trabalho foi analisar os perfis temporais de NDVI e obter o Kc a partir do produto de índice de vegetação NDVI (MOD13Q1), baseado na análise dos estádios fenológicos da cultura de soja irrigada, no município de Planura/MG, safra 2010/2011. A identificação das áreas plantadas com soja irrigada foi feita através de pesquisa de campo. As séries temporais do produto MOD13Q1 foram utilizadas para analisar o NDVI, permitindo a extração dos valores de NDVI para todos os pontos no período estudado. Os perfis temporais de NDVI apresentaram um padrão semelhante entre si e quanto ao ciclo da cultura. Os valores de KcNDVI variaram, em média, de acordo com os valores de Kc FAO, representando uma correlação linear (r2) de 0,72 para o produto MOD13Q1. Assim, o NDVI pode ser usado como uma alternativa na obtenção do Kc.