Author
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Pettigrew, William |
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Submitted to: Photosynthetica
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/4/2016 Publication Date: 2/22/2016 Citation: Pettigrew, W.T. 2016. Cultivar variation in cotton photosynthetic performance under different temperature regimes. Photosynthetica. DOI: 10.1007/s11099-016-0208-8. Interpretive Summary: Photosynthesis is the process where plants convert sunlight into chemical energy for growth. Cotton growth and yield could potentially be improved if cotton varieties photosynthesized at a higher rate. Higher temperatures, a predicted result from climate change scenarios, can limit photosynthetic performance. Identifying cotton varieties with superior photosynthesis and tolerance to higher temperatures would benefit cotton producers. A scientist in USDA-ARS, Crop Production Systems Research Unit, Stoneville, MS evaluated the photosynthetic performance of a diverse group of cotton varieties when grown under normal or high temperature conditions. Six cotton varieties were grown in the field and exposed to either a normal temperature regime or a slightly higher than normal temperature regime during 2006 through 2008 growing seasons. Photosynthetic parameters were measured on the plots each year during the peak blooming period. Under the temperature regimes imposed, none of the varieties photosynthetic rates were affected by the changing temperature, with the exception of PeeDee 3. The photosynthesis of this variety was lower under the higher temperature regime than under the normal temperature. There were varietal differences in photosynthesis rates and the variety FM 800BR consistently had a higher rate of photosynthesis than the other varieties. These photosynthetic differences among the varieties could potentially be utilized in breeding programs to develop improved varieties. Information from this research can be used by agronomists, crop physiologists, plant geneticists, consultants, and extension specialists. Technical Abstract: Cotton (Gossypium hirsutum L.) yields are impacted by overall photosynthetic production. Factors that influence crop photosynthesis are the plants genetic makeup and the environmental conditions. This study investigated cultivar variation in photosynthesis when plants were grown in the field under both ambient and higher temperature regimes. Six diverse cotton cultivars were grown in the field at Stoneville, MS under both an ambient and a high temperature regime during the 2006-2008 growing seasons. Mid-season leaf CO2-exchange rates (CER) and dark adapted chlorophyll fluorescence variable to maximal ratios (Fv/Fm) were determined on 2 leaves per plot. Temperature regimes didn’t have a significant main effect on either CER or Fv/Fm. In 2006, however, there was a significant cultivar X temperature interaction for CER caused by PeeDee 3 having a lower CER under the high temperature regime. Other cultivars’ CER were not affected by temperature. FM 800BR consistently had a higher CER across the years of the study. Despite demonstrating a higher leaf Fv/Fm, ST 5599BR exhibited a lower CER than the other cultivars. Although genetic variability was detected in photosynthesis and heat tolerance, the differences found were probably too small and inconsistent to be useful for a breeding program. |
