For rice, warmer earth brings uncertain future, UF research shows

GAINESVILLE, Fla. --- Temperature increases anticipated as part of global warming appear to significantly reduce rice yields, a finding that has worrisome implications for the third of the world's population that relies on rice as a primary staple.

University of Florida researchers have found above-average temperatures interfere with the life cycle and pollination process in rice plants. Modest temperature increases predicted by some climate change scenarios would reduce rice yields by 20 to 40 percent by 2100, while the most severe predicted temperature increases could force yields to zero.

The findings are among the latest to come out of the Carbon Dioxide and Climate Change Project at UF's Institute of Food and Agricultural Sciences. Researchers involved in the project, managed in cooperation with the U.S. Department of Agriculture and funded by UF and several federal agencies, have discovered that warmer temperatures also lead to declines in yields of peanuts, soybeans and dry beans such as kidney beans.

"I think we've demonstrated clearly that seed producing plants are much more at risk from rising temperatures than are vegetative plants such as forage plants," said Hartwell Allen, a USDA and UF crop and climate research scientist.

The latest experiment tested a variety of rice commonly grown in the Philippines, a tropical climate, and a variety grown in California, a temperate climate. Researchers planted the rice in chambers that were maintained at different temperature cycles simulating day and nighttime fluctuations. They found the plants steadily produced less rice as temperature diurnal cycles exceeded 73-91 degrees Fahrenheit for the tropical variety and 68-86 degrees for the temperate one. Those optimum cycles already fall a bit below current temperatures where the rice is cultivated, said Kenneth Boote, a UF agronomy professor involved in the projec
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Contact: Hartwell Allen
lhajr@gnv.ifas.ufl.edu
352-392-8194
University of Florida
29-Nov-2000