RESUMO

The expression of HaHB4® transcription factor reduces soybean sensitivity to abiotic stresses, such as water deficit. Studies that quantify the tolerance of HaHB4® soybean to the soil water content in comparison with cultivars currently sown in Brazil are lacking. The objective of this study was to determine the level of drought tolerance of soybean genotypes expressing the HaHB4® transcription factor (TS18-6-610108 and TS18-6-610084) and commercial cultivars (TMG 7063 IPRO and BS IRGA 1642 IPRO) subjected to water deficit during the vegetative phase. We used the fraction of transpirable soil water (FTSW) approach. Parameters related to leaf transpiration, dry matter accumulation, water use efficiency (WUE), and transpiration coefficient (TC) were evaluated in the four soybean genotypes and two treatments (T1-100% replacement of transpired water and T2-without replacement of transpired water). The FTSW threshold for the decline in transpiration was evaluated to identify the onset of water stress in soybean. TS18-6-610108 and BS IRGA 1642 IPRO maintains potential transpiration at low FTSW values. The TS18-6-610108 genotype has 14% higher WUE than the sensitive cultivar under water deficit. Under well-irrigated conditions, the HaHB4® genotypes showed the highest TC values, which indicate well-functioning physiological processes.

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The objectives of this study were to evaluate the response to fertilization and different weed control periods in the accumulation of dry matter of cassava leaves, stems, roots, and fresh mass roots yield. Two experiments were carried out on commercial fields in Ibarama, and Santa Maria municipalities located at the Rio Grande do Sul State, South Brazil, during the 2018/2019 growing season. Five treatments, varying chemical fertilizer applications and herbicides were used to represent management practices commonly used by farmers in Southern Brazil. The Simanihot process-based model simulated cassava growth, development, and productivity under potential conditions. Results show that the recommended dose of fertilizers and liming combined with pre-emergent herbicide and three mechanical weed clear management showed a 72% increase in root productivity compared to the management used by the average yield of smallholder farmers. Therefore, it is possible to reach 80% of the potential productivity by keeping the cassava crop free from weed interference and applying fertilizers. The presence of weeds during the first 100 days after planting reduced about 50% of the plant dry matter production in Ibarama and Santa Maria. Interestingly, it also affects 79.2% of fresh roots productivity in Ibarama. The objectives of this study were to evaluate the response to fertilization and different

Os objetivos deste trabalho foram avaliar a resposta à adubação e diferentes épocas de controle de plantas daninhas no acúmulo de matéria seca de folhas, hastes, raízes e produção de massa fresca de raízes de mandioca. Dois experimentos foram conduzidos em campos comerciais nos municípios de Ibarama e Santa Maria localizados no Rio Grande do Sul, Sul do Brasil, durante a safra 2018/2019. Cinco tratamentos, com aplicações variadas de fertilizantes químicos e herbicidas foram utilizados para representar as práticas de manejo comumente utilizadas pelos agricultores do Sul do Brasil. O modelo baseado no processo Simanihot foi usado para simular o crescimento, desenvolvimento e produtividade da mandioca sob condições potenciais. Os resultados mostram que a dose recomendada de fertilizantes e calagem combinados com herbicida pré-emergente e três manejos mecânicos de limpeza de plantas daninhas apresentaram um aumento de 72% na produtividade de raízes em relação ao manejo utilizado pela produtividade média dos pequenos agricultores. Portanto, é possível atingir 80% do potencial de produtividade mantendo a cultura da mandioca livre de interferência de plantas daninhas e com aplicação de fertilizantes. A presença de plantas daninhas durante os primeiros 100 dias após o plantio reduziu cerca de 50% da produção de matéria seca da planta em Ibarama e Santa Maria e 79,2% da produtividade de

RESUMO

The objectives of this study were to evaluate the response to fertilization and different weed control periods in the accumulation of dry matter of cassava leaves, stems, roots, and fresh mass roots yield. Two experiments were carried out on commercial fields in Ibarama, and Santa Maria municipalities located at the Rio Grande do Sul State, South Brazil, during the 2018/2019 growing season. Five treatments, varying chemical fertilizer applications and herbicides were used to represent management practices commonly used by farmers in Southern Brazil. The Simanihot process-based model simulated cassava growth, development, and productivity under potential conditions. Results show that the recommended dose of fertilizers and liming combined with pre-emergent herbicide and three mechanical weed clear management showed a 72% increase in root productivity compared to the management used by the average yield of smallholder farmers. Therefore, it is possible to reach 80% of the potential productivity by keeping the cassava crop free from weed interference and applying fertilizers. The presence of weeds during the first 100 days after planting reduced about 50% of the plant dry matter production in Ibarama and Santa Maria. Interestingly, it also affects 79.2%of fresh roots productivity in Ibarama.

Os objetivos deste trabalho foram avaliar a resposta à adubação e diferentes épocas de controle de plantas daninhas no acúmulo de matéria seca de folhas, hastes, raízes e produção de massa fresca de raízes de mandioca. Dois experimentos foram conduzidos em campos comerciais nos municípios de Ibarama e Santa Maria localizados no Rio Grande do Sul, Sul do Brasil, durante a safra 2018/2019. Cinco tratamentos, com aplicações variadas de fertilizantes químicos e herbicidas foram utilizados para representar as práticas de manejo comumente utilizadas pelos agricultores do Sul do Brasil. O modelo baseado no processo Simanihot foi usado para simular o crescimento, desenvolvimento e produtividade da mandioca sob condições potenciais. Os resultados mostram que a dose recomendada de fertilizantes e calagem combinados com herbicida pré-emergente e três manejos mecânicos de limpeza de plantas daninhas apresentaram um aumento de72% na produtividade de raízes em relação ao manejo utilizado pela produtividade média dos pequenos agricultores. Portanto, é possível atingir 80% do potencial de produtividade mantendo a cultura da mandioca livre de interferência de plantas daninhas e com aplicação de fertilizantes. A presença de plantas daninhas durante os primeiros 100 dias após o plantio reduziu cerca de 50% da produção de matéria seca da planta em Ibarama e Santa Maria e 79,2% da produtividade de raízes frescas em Ibarama.

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Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls’ Day across the Rio Grande do Sul State. For harvesting spikes for Mother’s Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mother’s Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.

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RESUMO

Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls Day across the Rio Grande do Sul State. For harvesting spikes for Mothers Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mothers Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.(AU)

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Gladiola is an important cut flower worldwide and scheduling field gladiola production is largely dependent on planting at the correct time since its development is controlled by the air temperature. The aim of this study was to configure a planting window of gladiola in order to harvest spikes to be sold on All Souls' Day and Mother's Day holidays in the state of Rio Grande do Sul, Brazil, taking into account the El Niño Southern Oscillation (ENSO) phases. The PhenoGlad model, a dynamic process-based simulation model that simulates gladiola phenology on a daily time step was used in this study. Daily minimum and maximum temperatures over 55 years (1961-2015) from 18 weather stations across Rio Grande do Sul state, Brazil, were used as input data in the PhenoGlad model. The optimum planting window was simulated for each maturity group, location and ENSO phase. For harvesting on All Souls' Day, the optimum planting window had greater variation among the different ENSO phases. For Mother's Day, only Very Strong El Niño events affected the development of gladiola, indicating the weak signal of the phenomenon at this time of the year. A case study in a commercial farm demonstrated the importance of these results for farmers. The planting window for production on Mother's Day in a Neutral year was successfully configured. Determining the optimum planting window by considering the ENSO effect led to a more precise scheduling of gladiola production in southern Brazil.

Assuntos

RESUMO

Gladiola is an important cut flower worldwide and scheduling field gladiola production is largely dependent on planting at the correct time since its development is controlled by the air temperature. The aim of this study was to configure a planting window of gladiola in order to harvest spikes to be sold on All Souls' Day and Mother's Day holidays in the state of Rio Grande do Sul, Brazil, taking into account the El Niño Southern Oscillation (ENSO) phases. The PhenoGlad model, a dynamic process-based simulation model that simulates gladiola phenology on a daily time step was used in this study. Daily minimum and maximum temperatures over 55 years (1961-2015) from 18 weather stations across Rio Grande do Sul state, Brazil, were used as input data in the PhenoGlad model. The optimum planting window was simulated for each maturity group, location and ENSO phase. For harvesting on All Souls' Day, the optimum planting window had greater variation among the different ENSO phases. For Mother's Day, only Very Strong El Niño events affected the development of gladiola, indicating the weak signal of the phenomenon at this time of the year. A case study in a commercial farm demonstrated the importance of these results for farmers. The planting window for production on Mother's Day in a Neutral year was successfully configured. Determining the optimum planting window by considering the ENSO effect led to a more precise scheduling of gladiola production in southern Brazil.(AU)

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RESUMO

The objective of this study was to compare the simulations of leaf appearance of landrace and improved maize cultivars using the CSM-CERES-Maize (linear) and the Wang and Engel models (nonlinear). The coefficients of the models were calibrated using a data set of total leaf number collected in the 11/04/2013 sowing date for the landrace varieties Cinquentinha and Bico de Ouro and the simple hybrid AS 1573PRO. For the BRS Planalto variety, model coefficients were estimated with data from 12/13/2014 sowing date. Evaluation of the models was with independent data sets collected during the growing seasons of 2013/2014 (Experiment 1) and 2014/2015 (Experiment 2) in Santa Maria, RS, Brazil. Total number of leaves for both landrace and improved maize varieties was better estimated with the Wang and Engel model, with a root mean square error of 1.0 leaf, while estimations with the CSM-CERES-Maize model had a root mean square error of 1.5 leaf.(AU)

O objetivo deste trabalho foi comparar a simulação da emissão de folhas de cultivares crioulas e melhoradas de milho realizada pelos modelos CSM-CERES-Maize (linear) e Wang e Engel (não linear). Para tanto, foram realizados dois experimentos nas safras agrícolas de 2013/2014 e 2014/2015 com delineamento de blocos ao acaso. Os coeficientes dos modelos foram calibrados a partir de um conjunto de dados de número de folhas totais de plantas, coletados na semeadura de 04/11/2013 para as cultivares crioulas Cinquentinha e Bico de Ouro e o híbrido simples AS 1573PRO. Para a variedade de polinização aberta melhorada BRS Planalto, os coeficientes foram estimados com dados da semeadura de 13/12/2014. A avaliação dos modelos foi realizada com dados independentes de semeaduras dos anos agrícolas 2013/2014 (Experimento 1) e 2014/2015 (Experimento 2) em Santa Maria, RS, Brasil. A melhor estimativa do número total de folhas, tanto para cultivares crioulas como melhoradas, foi obtida com o modelo Wang e Engel. A raiz do quadrado médio do erro do Wang e Engel foi de 1,0 folha, em comparação com o linear CSM-CERES-Maize, em que a raiz do quadrado médio do erro foi de 1,5 folha.(AU)

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ABSTRACT: The objective of this study was to compare the simulations of leaf appearance of landrace and improved maize cultivars using the CSM-CERES-Maize (linear) and the Wang and Engel models (nonlinear). The coefficients of the models were calibrated using a data set of total leaf number collected in the 11/04/2013 sowing date for the landrace varieties 'Cinquentinha' and 'Bico de Ouro' and the simple hybrid 'AS 1573PRO'. For the 'BRS Planalto' variety, model coefficients were estimated with data from 12/13/2014 sowing date. Evaluation of the models was with independent data sets collected during the growing seasons of 2013/2014 (Experiment 1) and 2014/2015 (Experiment 2) in Santa Maria, RS, Brazil. Total number of leaves for both landrace and improved maize varieties was better estimated with the Wang and Engel model, with a root mean square error of 1.0 leaf, while estimations with the CSM-CERES-Maize model had a root mean square error of 1.5 leaf.

RESUMO: O objetivo deste trabalho foi comparar a simulação da emissão de folhas de cultivares crioulas e melhoradas de milho realizada pelos modelos CSM-CERES-Maize (linear) e Wang e Engel (não linear). Para tanto, foram realizados dois experimentos nas safras agrícolas de 2013/2014 e 2014/2015 com delineamento de blocos ao acaso. Os coeficientes dos modelos foram calibrados a partir de um conjunto de dados de número de folhas totais de plantas, coletados na semeadura de 04/11/2013 para as cultivares crioulas 'Cinquentinha' e 'Bico de Ouro' e o híbrido simples 'AS 1573PRO'. Para a variedade de polinização aberta melhorada 'BRS Planalto', os coeficientes foram estimados com dados da semeadura de 13/12/2014. A avaliação dos modelos foi realizada com dados independentes de semeaduras dos anos agrícolas 2013/2014 (Experimento 1) e 2014/2015 (Experimento 2) em Santa Maria, RS, Brasil. A melhor estimativa do número total de folhas, tanto para cultivares crioulas como melhoradas, foi obtida com o modelo Wang e Engel. A raiz do quadrado médio do erro do Wang e Engel foi de 1,0 folha, em comparação com o linear CSM-CERES-Maize, em que a raiz do quadrado médio do erro foi de 1,5 folha.

RESUMO

The objective of this study was to simulate the yield of two cassava cultivars in two IPCC future climate scenarios, the SRES-A1B (Cmip3) and the RCP4.5 (Cmip5), for the state of Rio Grande do Sul, Brazil. The Simanihot model, with the Thornthwaite and Mather water balance sub-model, and the SRES-A1B (Cmip3 - Third Coupled Model Intercomparison Project) and RCP4.5 (Cmip5 - Fifth Coupled Model Intercomparison Project) scenarios of the Fourth and Fifth IPCC Assessment Report, respectively, was used. Cassava cultivars used in this study were "Fepagro - RS13" (forrage) and "Estrangeira" (human consumption). In both cultivars, there was an increase in tuberous roots yield in future climate scenarios. The cultivar for human consumption benefits more roots yield in the scenario with higher CO2 (Cmip3 scenario); whereas, the forage cultivar benefits more the Cmip5 scenario. Among the three future periods (2010-2039, 2040-2069 e 2070-2099), changes in tuberous roots yield are more evident in the end of the century period (2070-2099) and for early planting dates (01 September and 01 October). The northeastern region of the state has the greatest changes in tuberous roots yield in future climates, because this is the coldest region, with winter minimum temperature during between 6 and 8ºC.

O objetivo deste trabalho foi simular a produtividade de duas cultivares de mandioca em dois cenários climáticos futuros do IPCC, o SRES-A1B (Cmip3) e o RCP4.5 (Cmip5), para o Rio Grande do Sul. Foi utilizado o modelo Simanihot, com o submodelo de balanço hídrico do solo diário sequencial de Thornthwaite e Mather, e os cenários SRES- A1B (Cmip3 - 3o Projeto de Intercomparação de modelos globais) e o RCP4.5 (Cmip5 - 5o Projeto de Intercomparação de modelos globais) do 4o e 5o relatório do IPCC, respectivamente, regionalizados por downscaling dinâmico com modelo RegCM3 e RegCM4 (Modelo Climático Regional), respectivamente. As cultivares utilizadas no estudo foram a 'Fepagro - RS13' (uso forrageira) e 'Estrangeira' (uso para mesa). Em ambas há aumento na produtividade de raízes em cenários climáticos futuros. A cultivar de mesa se beneficia mais na produtividade de raízes no cenário com maior concentração de CO2 (cenário Cmip3), enquanto a cultivar forrageira, se beneficia mais no cenário Cmip5. Nos três períodos futuros (2010-2039, 2040-2069 e 2070-2099), as mudanças na produtividade são sempre mais expressivas no último período (2070-2099) e nas primeiras datas de plantio (01/09 e 01/10). A região do Rio Grande do Sul com maiores mudanças na produtividade é a nordeste, a qual, no clima atual é a mais fria do Estado, com temperatura mínima do ar no inverno entre 6 e 8°C.

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