JXB Advance Access published online on December 2, 2008
Journal of Experimental Botany, doi:10.1093/jxb/ern288
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© 2008 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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RESEARCH PAPER |
Genotypic variation in rice yield enhancement by elevated CO2 relates to growth before heading, and not to maturity group
1Climate Change Research Team, National Agricultural Research Center for Tohoku Region, Shimokuriyagawa, Iwate 020-0198, Japan
2Department of Global Agricultural Science, Graduate School of Agricultural and Life Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
3Department of Global Resources, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan
* Present address and to whom correspondence should be sent: Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan. E-mail: shimn{at}iwate-u.ac.jp
Maturity group (based on the number of days to maturity) is an important growth trait for determining crop productivity, but there has been no attempt to examine the effects of elevated [CO2] on yield enhancement of rice cultivars with different maturity groups. Since early-maturing cultivars generally show higher plant N concentration than late-maturing cultivars, it is hypothesized that [CO2]-induced yield enhancement might be larger for early-maturing cultivars than late-maturing cultivars. To test this hypothesis, the effects of elevated [CO2] on yield components, biomass, N uptake, and leaf photosynthesis of cultivars with different maturity groups were examined for 2 years using a free-air CO2 enrichment (FACE). Elevated [CO2] significantly increased grain yield and the magnitude significantly differed among the cultivars as detected by a significant [CO2]xcultivar interaction. Two cultivars (one with early and one with late maturity) responded more strongly to elevated [CO2] than those with intermediate maturity, resulting mainly from increases in spikelet density. Biomass and N uptake at the heading stage were closely correlated with grain yield and spikelet density over [CO2] and cultivars. Our 2 year field trial rejected the hypothesis that earlier cultivars would respond more to elevated [CO2] than later cultivars, but it is revealed that the magnitude of the growth enhancement before heading is a useful criterion for selecting rice cultivars capable of adapting to elevated [CO2].
Key words: Biomass, breeding, carbon dioxide, climate change, grain yield, photosynthesis, radiation-use efficiency, rice
Received 15 September 2008; Revised 20 October 2008 Accepted 28 October 2008
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