I recently participated in writing a book chapter on yield gains in U.S. rice, which will be included in “Yield Gains in Major U.S. Field Crops.” Writing book chapters is fairly common for agricultural scientists, and I have participated in several during my career. The chapter was written as a collaborative effort among rice breeders in Arkansas, California and Louisiana.
This endeavor brought into focus the significant improvements in rice yield potential in recent years through research efforts. Though U.S. rice cultivation began in 1685, when the first-ever rice seeds were introduced from Madagascar to the Carolinas, the modern U.S. rice industry started on the coastal prairies of southwest Louisiana in the 1880s. Few rice varieties were available early on, and only after the establishment of the LSU AgCenter Rice Research Station in 1909 was research conducted to evaluate and develop new varieties uniquely adapted to this region. The attached figure shows the history of Louisiana rice yields and also identifies some of the notable cultivars and technology that contributed to significant yield increases. The adoption of higher yielding cultivars during this timeframe, as opposed to improved production technology, is generally given most of the credit for this substantial yield increase. While there were some increases in yield potential during the first 70 years of Louisiana rice production, the most notable gains have occurred from the 1950s until today, with the most significant improvements occurring in the past 40 years. It is no coincidence that this timeframe coincides with the funding of Louisiana rice research by Louisiana rice producers and landowners, which commenced with the passing of checkoff legislation in 1971.
Development of landmark varieties played a critical role in the yield increase witnessed in the past three decades. Lemont, the first commercially successful U.S. semidwarf long-grain variety released in 1983 from Texas, dominated the southern rice landscape from 1985 until it was replaced by Cypress in the mid-1990s. Because of its high yield potential, early maturity, high and stable milling yields, and good grain appearance, Cypress and its derived imidazolinone-resistant (Clearfield) variety CL161 were widely grown in Louisiana and adjacent rice-growing states until the late 2000s.
Meanwhile, another Louisiana release, Cocodrie, became the leading long-grain variety in the southern United States in 2001. Cypress and Cocodrie typified the trait complexes central to the Rice Research Station rice breeding program, which include semidwarf and compact plant type, very early maturity, good milling yields, and wide adaptation. Because of its effective control of noxious weedy red rice, Clearfield rice rapidly gained popularity after its inception in the early 2000s. Even though early Clearfield varieties were inferior to the non-Clearfield conventional varieties in yield potential, the latest releases such as CL151 and CL111 possess higher yield potential than leading conventional varieties, which probably contributed to the accelerated yield increase in the last decade.
Although declining in production during the past 15 years, medium-grain rice represents a sizable acreage in Louisiana and Arkansas. The semidwarf variety Bengal, released in 1992, rapidly replaced the older tall variety Mars. Bengal accounted for almost all the medium-grain rice produced in Louisiana from the mid-1990s to the late 2000s, when it was finally replaced by Jupiter and more recently, Caffey.
In recent years, there has also been adoption of rice hybrids, developed and marketed by RiceTec, a private breeding company. These hybrids have also made a significant contribution to recent increases in southern U.S. rice yields. Hybrid acreage seeded to Clearfield hybrids are available only because of research conducted at the Rice Research Station.
Over the past 30 years, the annual genetic gain from new varieties has been estimated at 93 pounds (or .57 barrels) per acre. Many will concede that these increased yields are what have kept Louisiana in the rice production business. Remember, much of the success of these variety development activities over this timeframe has been possible because of the financial resources provided by checkoff funds. This should illustrate the importance of these funds in the future to continue to advance the economic viability of the Louisiana rice industry.
Permission granted April 15, 2014 by B. Leonards (LA Farm & Ranch) to republish article on www.lsuagcenter.com