In two previous articles we discussed rice variety development beginning with the crossing program through preliminary yield testing. This normally takes a minimum of 5-6 years. The lines that display superior characteristics in preliminary testing are considered for advancement to our Commercial/Advanced (CA) trials, as well as the Uniform Regional Rice Nursery (URN). Only about 5% of lines entered into the preliminary trials will be advanced.

The CA trials are conducted throughout the rice growing regions of Louisiana. In 2005, these tests where conducted at the Rice Research Station as well as at off-station locations in Acadia, Evangeline, Jeff Davis, Morehouse, Richland and Vermilion (2 locations) parishes. The off-station locations are conducted in cooperation with rice producers willing to provide land, land preparation, irrigation, and assistance with these trials in countless other ways. The farmer will provide an area that has independent flooding and draining capabilities. We will then plant the trial using the same small plot equipment used on the Rice Research Station.

After emergence the trial is handled just as it would be on the research station to optimize production and minimize any environmental variation that would affect our ability to evaluate true genetic differences among the lines in the trials. These trials are evaluated at least weekly, and data are collected for all characteristics just as is done on the research station. These trials are harvested using our small plot combine. Those trials harvested before August 15 will be ratoon-cropped to provide data on this important characteristic.

The URN is a cooperative endeavor conducted by the public rice breeding programs in Arkansas, Louisiana, Mississippi, Missouri and Texas. The nursery is a yield testing program conducted at the primary research location in each of those states. The “Uniform” comes from the fact that the same rice lines are tested at each of the five locations. The test currently contains 200 rice lines (or genotypes). The 200 entries in the test are made up of the elite lines from each breeding program that the breeders think might have the attributes for consideration as a new release, as well as the currently grown commercial varieties. Each of the breeding programs contributes a number of lines to the testing program. The yield test is then conducted at the research station in each state using the best cultural practices for that region.

All data from the testing program are then provided to each cooperator. Most of the experimental lines in our CA trials are also entered into the URN. Also, in both the URN and CA trials, the current commercial varieties are included to provide a benchmark for comparison purposes.

Between the CA and URN trials, our most advanced experimental lines are evaluated in 13 yield trials each year. The CA and URN trials are extremely important in making decisions on potential variety releases. It is critical that a line be evaluated under numerous environments. We are looking for superior and stable performance. We often see a line that will have excellent performance in two or three of these trials but average or inferior performance in several others. This line will be eliminated because of a lack of stability. Also, as with the preliminary trials, all of the entries in each of these trials are evaluated by Dr. Don Groth for relative susceptibility or resistance to major rice diseases.

Lines that show good and stable yield, milling, and agronomic characteristics across all these diverse environments will be re-entered into these trials the following year. A line that shows good potential as a future release will also be provided to Dr. Jason Bond for inclusion in his statewide Variety by Nitrogen Rate testing program. It will also be provided to Dr. Richard Dunand for evaluation to response to gibberillic acid. In addition, Dr. Eric Webster will evaluate these lines for differential response to selected rice herbicides. This research is conducted so that if a line is released as a variety, we can also provide a package of agronomic recommendations for its production.

If a line displays significantly better performance than the current commercial varieties, it may also be grown as a larger headrow population as a step toward potential increase. Remember, each line in these testing programs is also concurrently being grown as panicle rows for purification and increase. A typical headrow population is approximately 1,000 rows, which is often grown at our winter nursery facility in Puerto Rico. Seed from this size headrow increase will easily provide enough seed for up to a 20-acre foundation seed field on the Rice Research Station. The foundation seed production is under the direction of Mr. Larry White, who works closely with the breeders through each step of increase and purification.

We generally want at least three years of CA and URN data before we would consider a new variety release. We will be increasing seed on superior lines during this same time period so we often have foundation seed production during the third year of testing. If we feel that the line has consistently shown superior and stable performance after the third year of advanced testing and we have adequate foundation seed available, we will prepare a comprehensive data package on the line and provide this to the Director of the Louisiana Agricultural Experiment Station. If, after reviewing the data, the director agrees this is a candidate line for release, a committee will be appointed to evaluate the data and make a recommendation on the release. The final decision rests with the director. If the decision is positive, the director will ask for suggestions and approve the name for the new variety.

Foundation seed will then be made available to Louisiana seed growers based on the allocation formula developed a number of years ago by the Louisiana Seed Rice Growers Association. The Rice Research Station will continue to produce foundation seed for any released variety for as long as demand remains in the industry.

Thus, rice variety development is a long-term process that demands a great deal of time, hard work and dedication by a large number of people within the LSU AgCenter.