Growth response of 98 barley (Hordeum vulgare L.) genotypes to elevated CO₂ and identification of related quantitative trait loci using genome‐wide association studies

Abstract

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.

Effects of Elevated Atmospheric CO2 and its Interaction with Temperature and Nitrogen on Yield of Barley (Hordeum vulgare L.): A Meta-analysis

“…Higher responses of aboveground biomass (31% [CI: 26-36%]), grain number (30% [CI: 23-35%]), and grain yield (41% [CI: 34-47%]) were obtained for the plants grown in pots. However, the responses of TGW and harvest index of barley were not affected by rooting conditions (Table2and Figure7).DiscussionResponses of barley yield components to atmospheric CO 2 enrichment photosynthesis and reducing photorespiration(Drake et al, 1997;Mitterbauer et al, 2017;Schapendonk et al, 2000). The average increase in aboveground biomass by 23.8% under eCO 2 is similar to other reported estimates(Manderscheid et al, 2014; Thompson and Woodward, 1994;Weigel and Manderscheid, 2012).…”

Preserving the nutritional quality of crop plants under a changing climate: importance and strategies

“…The putative positive effect in agriculture is in fact denoted to as the "CO 2 fertilization effect" (Ainsworth and Long 2005;Bowes 1993;Bunce 2015;Dietterich et al 2015;Högy and Fangmeier 2008;Loladze 2014;Long et al 2004;Myers et al 2017;Ziska and Bunce 2007). This effect has already been observed in crop plants and vegetables, including wheat (Dong et al 2018c;Fernando et al 2012a;Han et al 2015;Högy and Fangmeier 2008), maize (Zong and Shangguan 2014), rice (Guo et al 2015;Pang et al 2006;Yang et al 2007), barley (Haase et al 2008;Mitterbauer et al 2017), bean (Bunce 2008;Ma et al 2017), soybean (Bunce 2015;Kumagai et al 2015), cowpea (Dey et al 2017), potato (Kumari and Agrawal 2014), lettuce, carrot, parsley (Dong et al 2018b;Long et al 2004;Mortensen 1994) and tomato (Jin et al 2009) among others. However, longer treatments with eCO 2 might lead to photosynthetic acclimation, due to increased soluble sugars leading to an imbalanced C:N ratio, accelerated leaf senescence and/or limited growth rate (Ainsworth and Long 2005;Ainsworth et al 2004;Kaplan et al 2012;Ludewig and Sonnewald 2000).…”

Cultivar‐dependent increases in mycorrhizal nutrient acquisition by barley in response to elevated CO2

“…Our data support this trend, as both cultivars had greater shoot biomass at eCO 2 compared to ambient [CO 2 ], although root biomass appeared to be less affected (Figure 2). While the biomass response to eCO 2 was similar in both cultivars examined here, it is important to note that significant variation in barley growth responses to eCO 2 has been demonstrated elsewhere (Mitterbauer et al, 2017 (Tausz-Posch et al, 2020). The extent to which this occurs in cereals remains to be resolved, although it is worth noting that photosynthetic acclimation to eCO 2 may depend on nitrogen availability and water use efficiency-two factors which themselves may be influenced by AMF.…”

“…Atmospheric CO 2 enrichment has been shown to affect carbon‐for‐nutrient exchange between AMF and plants, both non‐domesticated and domesticated (Elliott et al., 2020; Field et al., 2012). Barley cultivars show a varied response to eCO 2 , (Mitterbauer et al., 2017) but the extent to which this may be influenced or determined by AMF has not been investigated. In wheat, eCO 2 has been shown to have cultivar‐specific effects on the function of associated AMF (Thirkell, Pastok, et al., 2019), suggesting that AMF receptivity, function and responsiveness to atmospheric [CO 2 ] could be key traits for future sustainable wheat breeding programmes.…”