Growth response of 98 barley (Hordeum vulgare L.) genotypes to elevated CO2 and identification of related quantitative trait loci using genome-wide association studies
Elevated CO2 (eCO2) concentrations can stimulate crop growth, but little is known about intraspecific variability in the response to eCO2 and the underlying genetics in cereals. Field experiments over two years with 98 barley genotypes were conducted in open-top chambers (OTCs) under ambient CO2 (400 ppm) and eCO2 (700 ppm) concentrations. At crop maturity, different fractions of aboveground biomass (AGB) were measured, and genome-wide association studies (GWASs) were conducted to identify quantitative trait loci (QTL). Averaged across all genotypes, eCO2 significantly enhanced AGB by 15%, while the increase in culm and ear biomass alone was not significant. The AGB response to eCO2 of the individual genotypes ranged from c. -36% to +95% compared with ambient CO2 (aCO2), showing a large variability of growth responses. In GWAS, 51 associations between SNP markers and the relative changes (eCO2/aCO2) in biomass were detected on different chromosomes. Loci potentially involved in biomass alterations under eCO2 were identified. The wide range of variability in responses might be exploited by marker-based breeding for climate-resilient barley.
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