Steven Linscombe | 4/17/2009 1:10:21 AM
More rice acreage in Louisiana will be seeded to medium-grain varieties than has been the case in a number of years. Louisiana rice growers primarily grow long-grain varieties and hybrids and for the past few years have only grown a limited amount of medium-grain types. The grain types are differentiated by grain shape as well as cereal chemistry characteristics. Amylose is one of the types of glucose that makes up the starch contained in a rice grain. Typically, the long-grain types produced here will have an amylose content between 21-25 percent of the total makeup of the milled rice grain. Conversely, a medium-grain type will normally have an amylose content of 13-16 percent.
Another important grain characteristic is referred to as gelatinization temperature. This is the temperature at which a cooking rice grain will change texture to a softer gel-like substance. Long grains exhibit an intermediate to a high gelatinization temperature, while medium grains show a low one. These characteristics cause long grains to cook drier and flakier and medium grains to cook softer and sticker. Some consumers prefer the cooking characteristic of long grains, while others prefer medium-grain types. Across the United States, long-grain types dominate milled rice sales as this is the grain type preferred by most U.S. consumers. The southern U.S. rice production (approximately 2.5 million acres) is predominated by long-grain production, while California’s production (approximately 500,000 acres) is mainly medium grain.
In addition to consumer preference, the different cooking characteristics of the two grain types affect their suitability for certain food manufacturing processes. An example is the cereal industry. Most puffed rice products are made with medium-grain types. Other types of cereals typically use long-grain rice in their production. This preference is a matter of how the cereal chemistry characteristics of the grain type perform under the different processing operations. Another example is the use of rice for beer production. Some brewing is set up for the use of medium-grain types while others use long grains.
Louisiana has not always been predominated by long-grain production. In the early 1980s, the state was producing approximately 65 percent medium grains and 35 percent long grains. By the mid 1990s, this had reversed to 65 percent long grains and 35 percent medium grains. For the past 10 years, we have produced less than 5 percent medium grains.
Several factors contributed to this shift. A major one is the fact that 30 years ago, the medium-grain varieties available had better yield potential and disease resistance than the available long grains. Rice breeders released several superior long-grain types that reversed this difference, and soon the long grains were comparable with or superior to the medium grains being grown. Market dynamics also changed. Historically, a great deal of the rice Louisiana produces is exported, and over the years some of the markets that preferred medium grains became less important, while those that preferred long grains became more important. There were also some shifts in demand for the different grain types by U.S. food manufacturing companies.
Some of these same dynamics are responsible for the greater demand for medium grains this year. As mentioned earlier, California produces medium-grain types almost exclusively, and that state’s rice is currently selling for a high premium because of other fairly complex market dynamics. Southern U.S. medium grains are somewhat different from those produced in California, and some uses are not interchangeable. However, the California price dynamics are also responsible at least in part for the high prices currently seen for southern medium-grain types.
Louisiana producers will plant three different medium-grain varieties this year. Most of the acreage will be in Jupiter (released in 2005). A more limited amount of acreage will be planted in Neptune (released in 2008) and Bengal (released in 1992). Jupiter and Neptune were developed by Dr. Xueyan Sha, a rice breeder at the LSU AgCenter Rice Research Station in Crowley. Because many producers have not grown a medium grain for a number of years, we have received a number of questions on medium-grain production this year. The bottom line is that basically there is little difference between production practices for the two grain types. Seeding rates are similar as well as fertilizer requirements. While medium grains typically have a higher level of resistance to sheath blight disease than long grains, in most cases, a fungicide application will be recommended to optimize production.
Another consideration is second crop production. Typically, medium grains are not as high yielding or consistent in the production of a second crop in southwest Louisiana, where this is a common practice. However, Neptune is an exception to this. Research conducted at the Rice Station has shown this variety to be as good and as consistent as our currently widely grown long-grain varieties.
For additional information on all rice varieties, as well as other production tips, consult the LSU AgCenter publication 2010 Rice Varieties and Management Tips (#2270) available at your local extension office or on the LSU AgCenter website.
Permission granted April 15, 2009 by B. Leonards (LA Farm & Ranch) to republish article on www.lsuagcenter.com.