• Energy Research

AbstractMaize is one of the world’s most important cereals, cultivated in a wide range of environments. Besides the importance of maize and the gains in yield from selection schemes, commercial breeding drastically reduced the number of cultivars of this crop. Current common sense states that hybrids, when compared to open-pollinated cultivars, are a better adaptation strategy to cope with the impacts of climate change. However, the performance and resilience of cultivars with different levels of improvement are still not explored in this context. Four cultivars—a commercial hybrid, one commercially improved open-pollinated, one improved open-pollinated derived from participatory breeding, and one from a farmer’s selection—were tested using the CERES-Maize crop model. Field experiments conducted in Brazil were used for calibration and evaluation. Synthetic scenarios of climate change resulted from the application of the incremental method on historical series of observations (30 years), with temperature increments ranging from +0.5 up to +3.0 °C and precipitation changes from −30 up to +30%. Planting dates consisted in nine dates (August 1–December 1, each 15 days). Results demonstrate that the model could mimic the phenology and yield of two improved open-pollinated cultivars (MPA01 and Fortuna) and the hybrid (AS1548). One open-pollinated cultivar could not be validated due to its high phenotypic variability. Yield response surfaces showed distinct impacts among cultivars, with improved open-pollinated cultivar MPA01 having a higher yield stability when compared to the hybrid. Early planting dates produced lower yields with higher risk of crop failure for all cultivars. Late planting dates produced higher yields with higher failure risk. Considering risk and yield, the best planting window for all cultivars and scenarios is between September and October. Our results demonstrate, for the first time, that improved open-pollinated cultivars are equivalent or more resilient than hybrids to yield changes under different scenarios of abiotic stresses.

AbstractMaize is one of the world’s most important cereals, cultivated in a wide range of environments. Besides the importance of maize and the gains in yield from selection schemes, commercial breeding drastically reduced the number of cultivars of this crop. Current common sense states that hybrids, when compared to open-pollinated cultivars, are a better adaptation strategy to cope with the impacts of climate change. However, the performance and resilience of cultivars with different levels of improvement are still not explored in this context. Four cultivars—a commercial hybrid, one commercially improved open-pollinated, one improved open-pollinated derived from participatory breeding, and one from a farmer’s selection—were tested using the CERES-Maize crop model. Field experiments conducted in Brazil were used for calibration and evaluation. Synthetic scenarios of climate change resulted from the application of the incremental method on historical series of observations (30 years), with temperature increments ranging from +0.5 up to +3.0 °C and precipitation changes from −30 up to +30%. Planting dates consisted in nine dates (August 1–December 1, each 15 days). Results demonstrate that the model could mimic the phenology and yield of two improved open-pollinated cultivars (MPA01 and Fortuna) and the hybrid (AS1548). One open-pollinated cultivar could not be validated due to its high phenotypic variability. Yield response surfaces showed distinct impacts among cultivars, with improved open-pollinated cultivar MPA01 having a higher yield stability when compared to the hybrid. Early planting dates produced lower yields with higher risk of crop failure for all cultivars. Late planting dates produced higher yields with higher failure risk. Considering risk and yield, the best planting window for all cultivars and scenarios is between September and October. Our results demonstrate, for the first time, that improved open-pollinated cultivars are equivalent or more resilient than hybrids to yield changes under different scenarios of abiotic stresses.

The study of psychological barriers and the attribution of social meaning is a complex and subjective process, but essential for the development of strategies to adapt to climate change and land-use management. The objective of this paper is to point out and discuss aspects that comprise climate vulnerability, especially regarding the climate perceptions understood as an element for the development of community adaptation strategies. The first part presents two study cases and the second part presents propositions for developing climate adaptation strategies based on the results of these cases. The paper focuses on two aspects: the perception of climate dynamics and the relationship between vulnerability and local climate dynamics. In order to establish the relationship between climate dynamics and the level of vulnerability perceived, a qualitative approach was adopted. Field data collection consisted of observing local civil association meetings and conducting semi-structured interviews with local actors. Although both communities studied are strongly affected by climate events, their perception of climate influences is essentially different. The difference in perception arises mainly from the different context in which climate events acquire meaning, rather than any ability of assigning meaning to possible climate change. To understand the dynamics of establishing an adaptation strategy, the motivational problems would be a stimulus, a causative agent of reflections on the conditions of vulnerability to climate change and reflection about their limit-situations. The final propositions present “Adaptation learning process pre-steps framework” that emerges from the description of contrasts in perceptions/cognitions observed between the two study cases. It is a model for the visualization of different and better living conditions, the unknown-viable, which enable social actors to become aware of capacity of acting and governance.

The study of psychological barriers and the attribution of social meaning is a complex and subjective process, but essential for the development of strategies to adapt to climate change and land-use management. The objective of this paper is to point out and discuss aspects that comprise climate vulnerability, especially regarding the climate perceptions understood as an element for the development of community adaptation strategies. The first part presents two study cases and the second part presents propositions for developing climate adaptation strategies based on the results of these cases. The paper focuses on two aspects: the perception of climate dynamics and the relationship between vulnerability and local climate dynamics. In order to establish the relationship between climate dynamics and the level of vulnerability perceived, a qualitative approach was adopted. Field data collection consisted of observing local civil association meetings and conducting semi-structured interviews with local actors. Although both communities studied are strongly affected by climate events, their perception of climate influences is essentially different. The difference in perception arises mainly from the different context in which climate events acquire meaning, rather than any ability of assigning meaning to possible climate change. To understand the dynamics of establishing an adaptation strategy, the motivational problems would be a stimulus, a causative agent of reflections on the conditions of vulnerability to climate change and reflection about their limit-situations. The final propositions present “Adaptation learning process pre-steps framework” that emerges from the description of contrasts in perceptions/cognitions observed between the two study cases. It is a model for the visualization of different and better living conditions, the unknown-viable, which enable social actors to become aware of capacity of acting and governance.