a b s t r a c tThe response in production parameters to projected future levels of temperature, atmospheric carbon dioxide ([CO 2 ]), and ozone ([O 3 ]) was investigated in 138 spring barley accessions. The comprehensive set of landraces, cultivars, and breeder-lines, were during their entire life cycle exposed to a two-factor treatment of combined elevated temperature (+5• C day/night) and [CO 2 ] (700 ppm), as well as single-factor treatments of elevated temperature (+5• C day/night), [CO 2 ] (700 ppm), and [O 3 ] (100-150 ppb). The control treatment was equivalent to present average South Scandinavian climate (temperature: 19/12• C (day/night), [CO 2 ]: 385 ppm). Overall grain yield was found to decrease 29% in the two-factor treatment with concurrent elevation of [CO 2 ] and temperature, and this response could not be predicted from the results of treatments with elevated [CO 2 ] and temperature as single factors, where grain yield increased 16% and decreased 56%, respectively. Elevated [O 3 ] was found to decrease grain yield by 15%. Substantial variation in response to the applied climate treatments was found between the accessions. The results revealed landraces, cultivars, and breeder-lines with phenotypes applicable for breeding towards stable and high yield under future climate conditions. Further, we suggest identifying resources for breeding under multifactor climate conditions, as single-factor treatments did not accurately forecast the response, when factors were combined.
Rooting depth, a hard trait to measure in the field, was negatively correlated with canopy temperature, an easy trait to measure by airborne thermography, in large wheat populations under terminal drought
The paper has two main objectives: (i) to assess the eco-efficiency of spring barley cultivation for malting in Denmark in a future changed climate (700 ppm [CO 2 ] and +5ºC) through Life Cycle Assessment (LCA) and (ii) to compare alternative future cultivation scenarios, both excluding and including earlier sowing and cultivar selection as measures of adaptation to a changed climate. A baseline scenario describing the current spring barley cultivation in Denmark was defined, and the expected main deviations were identified (differences in pesticide treatment index, modifications in nitrate leaching and change in crop yield). The main input data originate from experiments, where spring barley cultivars were cultivated in a climate phytotron under controlled and manipulated treatments. Effects of changed climate on both crop productivity and crop quality were represented, as well as impacts of predicted extreme events, simulated through a long heat-wave. LCA results showed that the changed climatic conditions will likely increase the negative impacts on the environment from Danish spring barley cultivation, since all environmental impact categories experienced increased impact for all investigated scenarios, except under the very optimistic assumption that the pace of yield improvement by breeding in the future will be the same as it was in the last decades. The main driver of the increased environmental impact was identified as the reduction in crop yield. Therefore, potential adaptation strategies should mainly focus on maintaining or improving crop productivity. The LCA also showed that selection of proper cultivars for future climate conditions including the challenge from extreme events is one of the most effective ways to reduce future environmental impacts of spring barley. Finally, if yield measurements are based on relative protein content, the negative effects of the future climate seem to be reduced.
Future barley cultivars will have to produce under the constraints of higher temperature in combination with increased concentrations of atmospheric carbon dioxide and ozone as a consequence of climate change. A diverse set of 167 spring barley genotypes was cultivated under elevated levels of temperature (?5°C) and [CO 2 ] (700 ppm) as single factors and in combination as well as under elevated [O 3 ] (100-150 ppb) as single factor. The setting in general resembled changes projected by IPCC (AR5) to take place at the end of this century. A genome-wide association study (GWAS) was performed to identify markers for increased primary production under climate change conditions and reveal possible genes of interest. Phenotyped traits included grain yield, number of grains, number of ears per plant, aboveground vegetative biomass, harvest index and stability of the production parameters over the five applied treatments. The GWAS encompassed 7864 SNP markers (Illumina iselect), a compressed mixed linear model with the GAPIT package, and conservative validation of markers. A total of 60 marker-trait associations [-log 10 (P value) 2.97-5.58] were identified, e.g. grain yield under elevated temperature on barley chromosome 2H, static stability of grain yield on 7H, sites for exploitation of elevated [CO 2 ] on 4H Electronic supplementary material The online version of this article (
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