QUANTITATIVE AND QUALITATIVE EVALUATION OF SELECTED WHEAT VARIETIES RELEASED SINCE 1903 TO INCREASING ATMOSPHERIC CARBON DIOXIDE: CAN YIELD SENSITIVITY TO CARBON DIOXIDE BE A FACTOR IN WHEAT PERFORMANCE?

Authors: Ziska, Lewis; Morris, Craig; Goins, Ernest

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2004
Publication Date: 10/1/2004
Citation: Ziska, L.H., Morris, C.F., Goins, E.W. 2004. Quantitative and qualitative evaluation of selected wheat varieties released since 1903 to increasing atmospheric carbon dioxide: can yield sensitivity to carbon dioxide be a factor in wheat performance?. Global Change Biology 10:1810-1819.

Interpretive Summary: The sensitivity of yield and quality parameters to carbon dioxide concentration [CO2] was determined for individual lines of hard-red spring wheat released in 1903, 1921, 1965 and 1996. All cultivars were evaluated with respect to growth and vegetative characteristics, grain yield and nutritional quality in response to [CO2] increases. By maturity, vegetative growth of all cultivars significantly increased with the increase in [CO2]. Seed yield increased significantly as [CO2] increased, with yield sensitivity to rising [CO2]. Grain and flour protein, however, declined significantly with increasing [CO2] and with year of release for all cultivars, although absolute values were higher for the older cultivars. Overall, these data indicate that yield response at the whole-plant level to recent and projected increases in [CO2] has declined with the release of newer cultivars, as has protein content of grain and flour. However, if agronomic practice can be adapted to maximize individual plant performance, [CO2] responsive characteristics of older cultivars could, potentially, be incorporated as factors in future wheat selection.

Technical Abstract: The sensitivity of yield and quality parameters to carbon dioxide concentration [CO2] was determined for individual lines of hard-red spring wheat released in 1903, 1921, 1965 and 1996. All cultivars were evaluated with respect to growth and vegetative characteristics, grain yield and nutritional quality in response to [CO2] increases that corresponded roughly to the CO2 concentrations at the beginning of the 20th century, the current [CO2], and the future projected [CO2] for the end of the 21st century, respectively. Leaf area ratio (cm2 g1) declined and net assimilation rate (g m2 day1) increased in response to increasing [CO2] for all cultivars during early vegetative growth. By maturity, vegetative growth of all cultivars significantly increased with the increase in [CO2]. Seed yield increased significantly as [CO2] increased, with yield sensitivity to rising [CO2] inversely proportional to the year of cultivar release. Greater [CO2] yield sensitivity in older cultivars was associated with whole-plant characteristics such as increased tillering and panicle formation. Grain and flour protein, however, declined significantly with increasing [CO2] and with year of release for all cultivars, although absolute values were higher for the older cultivars. Overall, these data indicate that yield response at the whole-plant level to recent and projected increases in [CO2] has declined with the release of newer cultivars, as has protein content of grain and flour. However, if agronomic practice can be adapted to maximize individual plant performance, [CO2] responsive characteristics of older cultivars could, potentially, be incorporated as factors in future wheat selection.