Assessment of yield with altered soybean traits under climate change in the Southern Brazil

Abstract

The water deficit is the main factor responsible for soybean yield gap in southern Brazil and tends to increase under the climate change scenarios. Alternatives need be identified in order to create options to reduce the yield gap. One alternative is the selection of soybean cultivars with traits associated with drought tolerance. Thus, the aim this study is to evaluate soybean traits that can help to improve soybean yield under the climate change scenarios in southern Brazil by improving the crop tolerance to water deficit. For this, the CSM-CROPGRO-Soybean model will be used for the following proposes: to calibrate a Brazilian soybean cultivar, using results from field experiments conducted in different sowing dates in three locations in southern Brazil; to manipulate rooting depth extension, early stomata closure at high soil water contents, transpiration limited to a maximum rate, and N2 fixation drought tolerance in the model in order to identify their impact on yield under current and future climate scenarios; and to perform a sensitive analysis of CSM-CROPGRO-Soybean in relation to modified traits in the main soybean regions of southern Brazil. Weather series of climate change will be created based on anomalies defined by the downscaling of regional climate forecast models: RegCM3, HadRM3P and Eta/CPTEC, to the period 2071-2100, which consider different air temperature and CO2 concentration scenarios. The soybean yield from all locations will be evaluated in order to define guidelines for breeding programs, allowing the saving of resources and time in the new cultivars development process focused on adaptation to climate change. (AU)