Climate Change Effects on Plant Ecosystems – Genetic Resources for Future Barley Breeding

Summary

Climate Change Effects on Plant Ecosystems – Genetic Resources for Future Barley Breeding. A growing population and a considerable increase in living standards worldwide are increasing the demand on the primary production. At the same time, climate change is projected to lower the primary production due to increases in the atmospheric concentrations of carbon dioxide ([CO2]) and ozone ([O3]), rising temperatures and extreme climate events such as floods, storms and heatwaves. These predictions are compounded by the projections from the Intergovernmental Panel on Climate Change, which state that the world is heading towards a worst-case climate scenario unless actions are taken collectively in the very near future. Crop yields have stagnated since the start of this century; a trend also revealed in the cultivation of barley and wheat in the Nordic countries Denmark, Sweden, Norway and Finland, why actions are needed to develop climate resilient cultivars and secure future primary production. Within the network ‘Sustainable primary production in a changing climate’ 22-138 spring barley accessions have been grown in the climate phytotron RERAF under conditions mimicking climate change; 1) elevated temperature (+5°C), [CO2] (700 ppm) and [O3] (100-150 ppb) as single factors, 2) elevated temperature and [CO2] in combination and 3) a 10 day-heatwave (33°C) around the time of flowering in addition to elevated levels of temperature and [CO2]. The responses in grain yield, number of grains, number of ears, biomass, harvest index, grain protein concentration and stability over treatments were assessed. In addition, a genome-wide association study of recorded phenotypes and DNA-markers (from Illumina arrays) recognized novel marker-trait associations of production parameters under climate change conditions.
In a future climate scenario of elevated temperature and [CO2] the grain yield of barley was found to decrease by 29% and harvested grain protein by 22%. With an additional 10 dayheatwave around flowering grain yield was decreased by 52 %, revealing sombre forecasts to the future primary production. However, vast variation was identified within the individual barley accessions, which can be introduced into cultivars to achieve climate resilience. The results from the present dissertation have entered into manuscripts on the direct effect of climate change on barley productivity and quality as well as in life cycle assessment studies (LCA). Valuable genetic resources were identified for possible use in breeding of climate resilient cultivars and SNP-markers that link to traits favourable in changed environments. Basic knowledge of plant response to multifactor climate treatments has been added as well as data on numerous genotypes modeling the impact of climate change to future primary production have been supplied.