Future yield performance of ZS265 and ZS263 maize varieties and information dissemination for adaptation to climate change : a case of the Zimbabwean maize cropping system

Abstract: In an effort to design a sustainable maize cropping system in Zimbabwe, attain food security and build resilience against climate change, achievements in crop breeding are evident by the introduction of Drought Tolerant (DT) maize varieties. The study aims to analyze the impact of climate change on DT maize varieties that are characterized to be drought tolerant and yield productive under future climate conditions. The study integrates the social dimension of agroecosystems and sustainability by analyzing challenges faced by the Agricultural Technical and Extension Services (AGRITEX) of Zimbabwe in disseminating information on DT maize to farmers. As resilience building is characterized by the systems’ capacities to self-organize and still retain same functions when undergoing stresses, shocks and its ability to increase and build the capacity for learning and adaptation (socio-ecological resilience) (Gibbs, 2009). To analyze the response of DT maize productivity to climate change, the modelling approach was used. The crop model Agricultural production systems simulator (APSIM) was calibrated and validated with data from the Crop Breeding Institute research site, Makoholi located in the AgroEcological zone IV of Zimbabwe. Climate parameters input were based on downscaled RCP 8.5 and RCP 2.6 scenarios of AE zone IV of Zimbabwe. Relative to the baseline climate (1980-2005), in the near future climate (2020 – 2045) a mean annual maximum temperature rise of 6.1°C in RCP 8.5 and 3.3°C in RCP 2.6 was projected. The total growing season rainfall was projected to have higher variability in climate scenario RCP 8.5 and lower variability in climate RCP 2.6. The Root mean square error (RSME) indicated that APSIM could simulate the yield and days to tasselling of the two DT maize varieties for the growing season 2010-2012. Relative to ZS265 the inter-percentile range of yield change of ZS263 by +38%, +16% and +12% in the RCP 8.5, RCP2.6 and the baseline, respectively. A questionnaire survey was distributed to extension workers utilizing both quantitative and qualitative questions. Results obtained from 15 respondents indicated that hindrances and challenges in dissemination of information by AGRITEX on DT maize to farmers as an adaptation strategy was mainly due to financial, financial allocation and institutional (malfunctioning or non-existing communication channels between the research subsystem and their extension subsystem) challenges. To ensure food security in Zimbabwe in the coming decades under climate change and variability, it is required to find and analyze integrated approaches to implement alongside crop breeding strategies i.e. DT maize varieties, through agroecological crop management practices and principles, and improved social information systems which integrate the different knowledge subsystems in the same level.