|WANG, DIANE - CORNELL UNIVERSITY - NEW YORK|
|MCCOUCH, SUSAN - CORNELL UNIVERSITY - NEW YORK|
Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2016
Publication Date: 4/1/2016
Citation: Wang, D.R., Bunce, J.A., Tomecek, M.B., Gealy, D.R., McClung, A.M., McCouch, S.R., Ziska, L.H. 2016. Evidence for divergence of response in Indica, Japonica, and wild rice to high CO2 x temperature interaction. Global Change Biology. 22:3026-3038. doi:10.1111/gcb.13279.
Interpretive Summary: Although carbon dioxide (CO2) is recognized as a greenhouse gas, it also represents the sole source of carbon for photosynthesis and plant growth. As such, breeders have begun studies to examine which varieties of important cereal crops, such as rice, might respond best to rising CO2 levels and the basis for such a response. However, there have been only a few studies that have examined the impact of growth and yield of these cereals if both CO2 and temperature increase simultaneously. In this study, physiologists and plant breeders evaluated 11 genetically diverse rice varieties at current and projected CO2 concentrations under four temperature environments to examine a number of traits associated with seed yield. It was discovered that rice grown under projected increases of CO2 was more sensitive to high temperature stress compared to rice grown at current CO2 levels. The overall results indicated that, in fact, rising temperature would negate any CO2 stimulation in rice yield for all of the rice varieties studied; and could, for certain varieties, actually reduce yield relative to current conditions. These data will be of importance to plant biologists, rice breeders, food security experts, policymakers and the general public.
Technical Abstract: Previous studies suggest that the intraspecific variability of rice yield response to rising carbon dioxide concentration, [CO2], could serve as a basis of selection to improve genotypes for future high CO2 conditions. However, assessment of responses to elevated [CO2] must consider air temperature, which is also projected to increase with climate change. In this study, we evaluated 11 genetically diverse rice accessions under controlled conditions at two carbon dioxide concentrations (400 and 600 µmol mol-1) and 4 temperature environments (29oC day/21oC night; 29oC day/21oC night with additional anthesis heat stress; 34oC day/26oC night; and 34oC day/26oC night with additional anthesis heat stress) for a suite of traits including 5 yield components, 5 growth characteristics, 1 phenological trait, and 4 photosynthesis-related measurements. Multivariate analyses of line mean trait data from these 8 treatments divide our rice panel into two primary groups, INDICA and JAPONICA, consistent with past genetic classification. We find that reproductive behavior; measured as 4 yield components, for plants grown under elevated [CO2] was more sensitive to high temperature stress compared to that of plants grown under ambient [CO2]. Our data also provide evidence of differential response to [CO2] and temperature in INDICA versus JAPONICA. Overall, our results indicate that rising temperature could negate any positive yield stimulation from increased [CO2] and that elevated [CO2] could exacerbate negative responses associated with warmer temperatures among a diverse set of rice lines.