Hazards of Temperature-increase on Food Availability in Changing Environments: Global Warming Could Cause Failure of Seed Yields of Major Crops L. H. Allen, K. J. Boote, P. V. V. Prasad, A. M. Snyder, J. M. G. Thomas, and J. C. Vu USDA-Agricultural Research Service and Agronomy Department, University of Florida, Gainesville, FL USA
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L. H. Allen, K. J. Boote, P. V. V. Prasad, A. M. Snyder, J. M. G. Thomas, and J. C. Vu
Hazards of Temperature-increase on Food Availability in Changing Environments: Global Warming Could Cause Failure of Seed Yields of Major Crops. L. H. Allen, K. J. Boote, P. V. V. Prasad, A. M. Snyder, J. M. G. Thomas, and J. C. Vu - PowerPoint PPT Presentation
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Hazards of Temperature-increase on Food Availability in Changing Environments:
Global Warming Could Cause Failureof Seed Yields of Major Crops
L. H. Allen, K. J. Boote, P. V. V. Prasad,
A. M. Snyder, J. M. G. Thomas, and J. C. VuUSDA-Agricultural Research Service and Agronomy
Department, University of Florida, Gainesville, FL USA
Why study global warming impacts on seed-grain crops?
CO2 might rise to 540-970 ppm, and temperature by 1.4-5.8 °C by 2100
Elevated CO2 effects on plants are well understood and are mostly beneficial
Elevated temperature effects are poorly understood and are detrimental to reproductive processes of seed-grain crops
SCOPE--1
• Show experimental evidence for progression of seed yield failures with increasing temperature
• Plants were grown in deep soil in outdoor, sunlit controlled-environment chambers
• Controlled factors: Temperature, Humidity (Dewpoint), CO2 Concentration, Soil Water
• Plants were exposed to the same solar radiation during each individual study
As mean temperature exceeded 31°C (36/26°C), pollen viability (top) and percent seed-set (bottom) declined, reaching zero at 39°C (44/34°C).
Low seed yield is caused by low seed-set, which in turn is caused by low pollen viability.
23 26 29 32 35 38 41 440
25
50
75
100
Mean air temperature (°C)
Rice
See
d-s
et (
%)
Dry bean
Peanut
Summary: Species differ in response of yield and percent seed-set to increasing temperature. Major cause is decreased pollen viability. Soybean is like peanut. Sorghum is like rice.
Importance of Temperature Effects on Reproductive Processes
Elevated temperature affects reproductive processes more than vegetative biomass.
There is no beneficial interaction of high CO2 on the detrimental temperature effect.
Yields decreased to zero for cultivars studied at about:
32 °C for dry bean
35-36 °C for rice and grain sorghum
40 °C for soybean and peanut
Temperature sensitivity might vary for other cultivars.
Potential Impacts of Global Warming on Food Availability (Food Production)
• Example of rice, cultivar IR30– A 5 °C rise in temperature might decrease yield
to only 40% of current yield for Florida conditions.
Research and Information Needs
• Search for high temperature tolerant cultivars.
• Determine physiological and genetic mechanisms of temperature sensitivity and breed crop plants for less sensitivity.
• Ameliorate high temperature impacts with alternate crops, planting dates, etc.