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Contrasting responses of seed yield to elevated carbon dioxide under field conditions within Phaseolus vulgaris
- Abstract::
- The rising concentration of carbon dioxide [CO₂] in the atmosphere represents an increase in a growth-limiting resource for C₃ crop species. Identification of lines or characteristics of lines which have superior yield at elevated [CO₂] could aid in adaptation to this global change. While intraspecific variation in responses to elevated [CO₂] has been found in several species, intraspecific differences in crop yield responses to elevated [CO₂] under field conditions have seldom been documented. In this 4-year study, the responses of photosynthesis, growth, pod number, seed number and size, and seed yield to the elevation of [CO₂] to 180μmolmol⁻¹ above the current ambient concentration were examined in four varieties of Phaseolus vulgaris in the field, using open-top chambers. There was a significant variety by [CO₂] interaction for seed yield, with seed yield at elevated [CO₂] ranging from 0.89 to 1.39 times that at ambient [CO₂] (mean 1.17x) in the different varieties, when averaged over 4 years. The highest yielding variety at elevated [CO₂] was not the highest yielding variety at ambient [CO₂]. The varieties with the largest and smallest yield responses both had an indeterminate growth habit. Down-regulation of photosynthesis at elevated [CO₂] only occurred in the two indeterminate varieties, and there was no significant correlation between the response of single leaf photosynthetic rate and the response of seed yield to elevated [CO₂] among varieties, nor between the responses of stem mass and seed yield. The change in the number of pods at elevated [CO₂] was the primary determinant of the response of seed yield. These results indicate that significant variation in the response of seed yield to elevated [CO₂] under field conditions does exist among varieties of P. vulgaris, and that variation in the response of pod and seed number may be more important than variation in photosynthetic response.
- Author(s):
-
Bunce, James A.
- Subject(s):
-
Phaseolus vulgaris , beans , C3 plants , seed productivity , vegetative growth , gas exchange , atmospheric circulation , carbon dioxide
- Description:
- Includes references
- Source:
- Agriculture, ecosystems & environment 2008 Dec., v. 128, no. 4
- Language:
- English
- Year:
- 2008
- Publisher:
- Amsterdam; New York: Elsevier
- Collection:
-
Journal Articles, USDA Authors, Peer-Reviewed
- File:
-
Download [PDF]
- Rights:
- Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
