Three-year field evaluation of early and late 20th century spring wheat cultivars to projected increases in atmospheric carbon dioxide
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ArticlePublication details: 2008Subject(s):
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Field Crops Research v. 108, no. 1, p. 54-59Summary: Carbon dioxide (CO2), along with light, water and nutrients, represents an essential resource needed for plant growth and reproduction. Projected and recent increases in atmospheric carbon dioxide may allow breeders and agronomists to begin intra-specific selection for yield traits associated with CO2 sensitivity. However, selection for maximum yield, particularly for cereals, is continuous, and it is possible that modern cereal cultivars are, in fact, the most CO2 sensitive. To test CO2 responsiveness, we examined two contrasting spring wheat cultivars, Marquis and Oxen, over a 3-year period under field conditions at two different planting densities. Marquis was introduced into North America in 1903, and is taller, with greater tiller plasticity (i.e. greater variation in tiller production), smaller seed and lower harvest index relative to modern wheat cultivars. Oxen, a modern cultivar released in 1996, produces fewer tillers, and has larger seed with a higher harvest index relative to Marquis. As would be expected, under ambient CO2 conditions, Oxen produced more seed than Marquis for all 3 years. However, at a CO2 concentration 250 µmol mol-1 above ambient (a concentration anticipated in the next 50–100 years), no differences were observed in seed yield between the two cultivars, and vegetative above ground biomass (e.g. tillers), was significantly higher for Marquis relative to Oxen in 2006 and 2007. Significant CO2 by cultivar interaction was observed as a result of greater tiller production and an increased percentage of tillers bearing panicles for the Marquis relative to the Oxen cultivar at elevated carbon dioxide. This greater increase in tiller bearing panicles also resulted in a significant increase in harvest index for the Marquis cultivar as CO2 increased. While preliminary, these results intimate that newer cultivars are not intrinsically more CO2 responsive; rather, that yield sensitivity may be dependent on the availability of reproductive sinks to assimilate additional carbon. Overall, understanding and characterizing vegetative vs. reproductive sink capacity between cultivars may offer new opportunities for breeders to exploit and adapt varieties of wheat to projected increases in atmospheric carbon dioxide concentration.
| Item type | Current library | Collection | Call number | Status | Date due | Barcode | Item holds | |
|---|---|---|---|---|---|---|---|---|
| Article | CIMMYT Knowledge Center: John Woolston Library | Reprints Collection | Available |
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0378-4290
Carbon dioxide (CO2), along with light, water and nutrients, represents an essential resource needed for plant growth and reproduction. Projected and recent increases in atmospheric carbon dioxide may allow breeders and agronomists to begin intra-specific selection for yield traits associated with CO2 sensitivity. However, selection for maximum yield, particularly for cereals, is continuous, and it is possible that modern cereal cultivars are, in fact, the most CO2 sensitive. To test CO2 responsiveness, we examined two contrasting spring wheat cultivars, Marquis and Oxen, over a 3-year period under field conditions at two different planting densities. Marquis was introduced into North America in 1903, and is taller, with greater tiller plasticity (i.e. greater variation in tiller production), smaller seed and lower harvest index relative to modern wheat cultivars. Oxen, a modern cultivar released in 1996, produces fewer tillers, and has larger seed with a higher harvest index relative to Marquis. As would be expected, under ambient CO2 conditions, Oxen produced more seed than Marquis for all 3 years. However, at a CO2 concentration 250 µmol mol-1 above ambient (a concentration anticipated in the next 50–100 years), no differences were observed in seed yield between the two cultivars, and vegetative above ground biomass (e.g. tillers), was significantly higher for Marquis relative to Oxen in 2006 and 2007. Significant CO2 by cultivar interaction was observed as a result of greater tiller production and an increased percentage of tillers bearing panicles for the Marquis relative to the Oxen cultivar at elevated carbon dioxide. This greater increase in tiller bearing panicles also resulted in a significant increase in harvest index for the Marquis cultivar as CO2 increased. While preliminary, these results intimate that newer cultivars are not intrinsically more CO2 responsive; rather, that yield sensitivity may be dependent on the availability of reproductive sinks to assimilate additional carbon. Overall, understanding and characterizing vegetative vs. reproductive sink capacity between cultivars may offer new opportunities for breeders to exploit and adapt varieties of wheat to projected increases in atmospheric carbon dioxide concentration.
English
Elsevier
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