|Allen, Leon - Hartwell|
|Gesch, Russell - Russ|
Submitted to: Journal of Agricultural Meteorology of Japan
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2005
Publication Date: 5/1/2005
Citation: Boote, K.J., Allen Jr, L.H., Prasad, P.V., Baker, J.T., Gesch, R.W., Snyder, A.M., Pan, D., Thomas, J.M. 2005. Elevated temperature and CO2 impacts on pollination, reproductive growth, and yield of several globally important crops. Journal of Agricultural Meteorology of Japan. 60:469-474. Interpretive Summary: Carbon dioxide (CO2) of the atmosphere is predicted to rise from 370 parts per million (ppm) today up to 540-970 ppm by 2100, and potentially cause global warming of 2.5 to 10 degrees Fahrenheit (F). Higher temperatures could hurt seed yields. Therefore, ARS and University of Florida scientists at Gainesville measured the effects of elevated temperature and CO2 on yields of rice, dry bean, soybean, and peanut grown at two levels of CO2 (350 ppm, near ambient, and 700 ppm, double ambient) and at five maximum/minimum daily temperature cycles ranging from 82/64 to 104/86 degrees F. Each crop had a specific temperature that was optimum for seed yield, and yields decreased progressively to zero at about 18 degrees F above each specific optimum temperature. Compared to rice, dry bean was more sensitive to high temperatures whereas soybean and peanut were more tolerant. Pollination failure was the chief cause of yield declines at high temperatures. Yield increases caused by elevated CO2 were just as sensitive to high temperatures as yields at ambient temperature. Knowledge gained will enable scientists to search for crops that can yield well at higher temperatures, and thus ameliorate potential adverse impacts of global warming.
Technical Abstract: Carbon dioxide (CO2) might rise to 540-970 parts per million (ppm) by 2100, and cause global temperature to rise 1.4-5.8 Celsius. Studies to determine effects of elevated temperature and doubled CO2 on reproductive growth and yield of rice, dry bean, soybean, and peanut were conducted. Diurnal treatments were 28/18, 32/32, 36/26, 40/30, and 44/34 Celsius at 350 or 700 ppm CO2. Vegetative growth was tolerant but reproductive growth failed rapidly with increasing mean daily temperature. Above 25 Celsius rice grain yield declined progressively, reaching zero at 35 Celsius attributed to failed pollination. Dry bean was more sensitive, with highest yield at 23 Celsius, reaching zero at 32 Celsius. Soybean and peanut were more tolerant than rice; their grain yields declined above 26 Celsius and reached zero at 40 Celsius. Pollen viability of dry bean and peanut followed a temperature response similar to grain yield. Rice maintained grain-size with rising temperatures whereas dry bean, soybean, and peanut seed size declined. There were no beneficial interactions of CO2 with elevated temperature. Detrimental effects of elevated temperature on reproductive processes will be very important under future global environmental change.