food supply. Curry et al. (1995) predicted decreased soybean yields in the southeastern USA associated with Climate change due to increased [CO 2 ] and elevated temperature a 5ЊC increase in temperature predicted by several may impact the composition of crop seed. This study was conducted to determine the potential effects of climate change on composition global climate change models. Allen and Boote (2000) and gene expression of soybean [Glycine max (L.) Merr. cv. 'Bragg'] reviewed the documented impacts of climate change on seed. Soybean plants were grown in sunlit, controlled environment soybean, including decreased yield and quality due to chambers under diel, sinusoidal temperatures of 28/18, 32/22, 36/26, higher growth temperature. Sunlit, controlled environ-40/30, and 44/34؇C (day/night, maximum/minimum), and two levels ment chambers have been used to examine the effects of [CO 2 ], 350 and 700 mol mol Ϫ1 , imposed during the entire life and interactions of increased [CO 2 ] and temperature cycle. The effect of temperature on mature seed composition and on plants (Pickering et al., 1994), revealing important transcripts in developing seed was pronounced, but there was no effect alterations of physiology, growth, and seed yield (Baker of [CO 2 ]. Total oil concentration was highest at 32/22؇C and decreased and Allen, 1993; Allen and Boote, 2000). with further increase in temperature. Oleic acid concentration in-The unique chemical composition of soybean has creased with increasing temperature whereas linolenic acid decreased. Concentrations of N and P increased with temperature to 40/30؇C, made it one of the most valuable agronomic crops worldthen decreased. Total nonstructural carbohydrates (TNC) decreased wide. Consumed for thousands of years in Asia, soybean as temperatures increased, and the proportion of soluble sugars to has steadily gained importance as food in the USA, and starch decreased. Transcripts of a gene that is downregulated by auxin many new products have been developed using soybean (ADR12) were dramatically downregulated by elevated temperature, seed as raw material (Liu, 1997). Oil and protein compossibly reflecting the altered course of seed development under enviprise ≈20 and 40%, respectively, of the dry weight of ronmental stress. Transcripts of -glucosidase, a gene expressed dursoybean seed, and approximate values of other compoing normal soybean seed development, were detected in seed grownnents include carbohydrates (30%), crude fiber (5%), at 28/18؇C but not in seed grown at 40/30؇C, which also suggests and ash (5%) (Hymowitz et al., 1972). In addition, soythat normal programs affecting seed composition were perturbed by bean contains minerals such as Fe, Cu, Mn, Ca, Mg, elevated temperature. These results confirm previous studies indicating that high temperature alters soybean seed composition, and sug-Zn, Co, P, and K. Vitamins B 1 , B 2 , and B 6 , as well as gest possible mechanisms by which climate change may affect soybean isoflavones, are also available in soybean (A...