Submitted to: National Symposium on New Crops and New Uses
Publication Type: Proceedings
Publication Acceptance Date: 12/20/2001
Publication Date: 10/1/2002
Citation: GESCH, R.W., BARBOUR, N.W., FORCELLA, F., VOORHEES, W.B. CUPHEA GROWTH AND DEVELOPMENT: RESPONSES TO TEMPERATURE. JANCK, J., WHIPKEY, A., EDITORS. ASHS PRESS, ALEXANDRIA, VA. TRENDS IN NEW CROPS AND NEW USES. PROCEEDINGS OF THE FIFTH NATIONAL SYMPOSIUM. 2002. P. 213-215. Interpretive Summary: Cuphea is a plant that grows naturally in temperate climates and is known to produce large quantities of oil in its seeds that are similar to that produced by palm trees. The U.S. presently imports about 1.7 billion pounds of palm oil for the manufacture of soaps, detergents and a variety of personal care products. Presently, Cuphea is being developed as an oilseed crop that could be grown in the U.S., thus replacing imported palm oil. Efforts over the past decade to domesticate wild Cuphea species have been successful in producing varieties with improved agronomic traits. To identify the best region(s) in the U.S. to produce Cuphea and develop optimum management practices, we need to understand the effects of temperature on its growth potential. In the study, we investigated photosynthesis, growth and development of Cuphea under a wide range of temperatures to help us predict the best type of environment for Cuphea production. Our results indicate that flowering and seed development of Cuphea are adversely affected by high temperatures and that production will be best suited to regions with moderate growing season temperatures and relatively high rain fall. Information from this study will help bring Cuphea into commercial production. This will reduce U.S. reliance on imported oils from southeast Asian countries, where supplies may be unstable; ease U.S. reliance on petroleum; and give farmers in the upper Midwest a new crop that can be rotated in ag-systems that are already suffering side effects from minimal rotations.
Technical Abstract: Semi-domesticated Cuphea (sp.) genotypes show promise for commercial production of medium-chain fatty acids used in industrial chemical manufacturing. Successful management and production of Cuphea depends on a better understanding of its response to environmental growth-limiting factors, particularly temperature. We investigated the effects of temperature on photosynthesis, growth and development of a semi- domesticated genotype of Cuphea, PSR23. 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. Life cycle, growth rate, and biomass accumulation of plants increased with temperature up to a daily maximum growth 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. Based on regression analysis the temperature optimum for photosynthesis was 23 deg C, which was 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 carbon fixation at the leaf level also declined sharply with temperature, decreasing as much as 70% between 18 and 35 deg C daytime growth temperature. In terms of seed production, Cuphea (PSR23) appears to be best suited for regions with moderate growing season temperatures and high annual precipitation.