Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Proceedings
Publication Acceptance Date: November 13, 2001
Publication Date: April 1, 2002
Citation: GESCH, R.W., BARBOUR, N.W., FORCELLA, F., VOORHEES, W.B. CUPHEA GROWTH AND DEVELOPMENT: RESPONSES TO TEMPERATURE. JANICK, J., WHIPKEY, A., EDITORS. ASHS PRESS, ALEXANDRIA, VA. TRENDS IN NEW CROPS AND NEW USES. 2002. P. 213-215. Technical Abstract: Recently developed semi-domesticated Cuphea (sp.) genotypes show good potential for commercial production of medium-chain fatty acids used in industrial chemical manufacturing. Successful crop management and production will depend on a basic knowledge of Cuphea's response to environmental growth-limiting factors. Little is known about Cuphea's growth response to temperature. We conducted a controlled-environment study to test the effects of temperature on growth and development of a semi-domesticated genotype of Cuphea, developed by Dr. S. Knapp at Oregon State University. Plants were grown under daily sinusoidal temperature regimes with daytime-maximum and nighttime-minimum temperatures of 18/12, 24/18, 30/24 and 35/27 deg C. The life cycle, growth rate and biomass accumulation of plants increased to daytime maximum temperature of 30 deg C, but declined sharply at 35 deg C. Photosynthesis at growth temperature was less responsive than growth and development over the range of 18/12 to 35/27 deg C. The apparent temperature optimum for photosynthesis, about 23 to 24 deg C, was 3 to 4 deg C lower than that for growth. Seed mass decreased by 50% between 18 and 30 deg C, while plants under the 35/27 deg C regime failed to set seed. Water use efficiency of CO2 gas exchange in upper canopy leaves also declines sharply with temperature, decreasing as much as 70% between 18 and 35 deg C daytime temperature. Although Cuphea appears to adapt well to cool to moderate temperatures, it also has a relatively high water requirement for growth. In the absence of irrigation, production of current semi-domesticated genotypes of Cuphea may be best suited for areas with cool to moderate growing season temperatures and high annual precipitation.