Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2002
Publication Date: 12/5/2002
Citation: GESCH, R.W., FORCELLA, F., BARBOUR, N.W., PHILLIPS, B.S., VOORHEES, W.B. YIELD AND GROWTH RESPONSE OF CUPHEA TO SOWING DATE. CROP SCIENCE. 2002. v. 42(6). p. 1959-1965. Interpretive Summary: Seeds of Cuphea plants produce a type of oil that is used for the chemical manufacturing of soaps and detergents. It can also be used for making several other oil-based products. Presently, in the United States there are no oilseed crops grown that can economically replace this type of oil. Therefore, the U.S. imports this oil, which is extracted from palm tree related species and also from petroleum. The market for this oil is quite large. Cuphea, which we have found grows well in short- season temperate climates, could serve as a domestic source of oil to be used for manufacturing soaps and detergents and other products. Efforts over the past decade to domesticate wild Cuphea species have been successful in producing varieties with improved agronomic traits. However, little is known about the best agricultural management practices to use for producing it as a viable crop. Therefore, we are conducting research that will lead to optimum protocols for Cuphea production in the northern Corn Belt. A two-year field study was initiated in Morris, Minnesota, in 1999 to target the best time for planting Cuphea. Our results showed that planting in early to mid-May gave the best seed yield results, which were as high as 982 pounds per acre. Delaying planting until June resulted in smaller plants with fewer branches and that yielded less seed than those planted in May. Planting earlier than May also reduced seed yields, although plants grew as large as those planted in May. Our results will benefit farmers by developing strategies to produce Cuphea in the northern Corn Belt where there is great need for economical new crops to rotate with corn and soybean.
Technical Abstract: Select germplasm of Cuphea, recently developed from an interspecific hybridization of C. viscosissima Jacq. and C. lanceolata f. Silenoides W.T. Aiton, show good potential for commercial production in short- season temperate climates. Cuphea seed oil could serve as a domestic source of medium-chain fatty acids which are in high demand by the chemical manufacturing industry. However, little is known about the proper management practices for its agronomic production. A field study was conducted in west central Minnesota to determine optimum time of planting in the northern Corn Belt region and describe influences of sowing date on growth and seed yield components of a semi-domesticated germplasm line (PSR23). Seed was sown on April 15, May 1, May 15, June 1, and June 15 in both 1999 and 2000. Planting in May resulted in greatest seed and seed-oil yields, which were as high as 1.09 and 0.29 Mg ha-1, respectively. Seed yield declined as much as 31% when planted April 15 and 65% when sowing was delayed until June 15. Plants developed from seed sown prior to June tended to form more branches and accumulate a greater amount of aboveground biomass. Typically, there was a distinct decrease in biomass accumulation and most seed yield components when planting date was delayed until June. Cuphea PSR23 can be successfully grown to maturity in the northern Corn Belt, with early to mid May being the best time for sowing.