- Specialists Speaking -
Dr. Nathan Buehring
As the 2007 rice crop has ended, variety selection decisions for 2008 are at the forefront. The number of rice varieties to choose from is small compared to soybeans and corn; however, variety selection and placement is still a key component in maximizing rice yields and returns.
Combating red rice is still a major issue to consider when making planting decisions. The reality of this was made clear in 2007 because seed from Clearfield cultivars was limited. Clearfield technology will be a vital tool to keep red rice-infested acres in production.
Averaged over 2006 and 2007, CL161 and CL171-AR produced similar yields at over 20 locations. Furthermore, there was generally no more than three to four bu/acre between these varieties at each location. Whole milling yields of CL161 were 0.6 percent better than CL171-AR. In two strip trials, CL-161 and CL-171-AR produced similar yields. However, CL171-AR produced 12.5 percent lower whole milled kernels.
The probable cause for the lower milling yields is that these strip trials were planted in mid-April and harvested the first week of October. As a result, these trials were past the optimal grain moisture content (15-18 percent) when harvested, which led to more stress on the grain by heavy dew and rainfall. Therefore, it appears that CL171-AR will not maintain good whole milling yields if it is not harvested in a timely manner as CL161. Also, CL171-AR averaged to be about one inch taller than CL161.
Disease susceptibility of CL171-AR is comparable to CL161. Our trials, along with other rice-producing states, indicate that fungicide application will probably be necessary for sheath blight control in CL171-AR. Both of these varieties would rate susceptible to kernel smut and moderately susceptible to straighthead. CL171-AR appears to have more resistance to blast than CL161. With a limited amount of information on lodging, it showed CL171-AR is slightly more resistant to lodging than CL161.
In comparison of conventional varieties, Wells and Cocodrie produced similar yields, and Sabine yielded 11 percent less than Wells and Cocodrie. Whole milling yields of Wells averaged 4.4 percent lower than Cocodrie and 5.2 percent lower than Sabine. This year, many producers have indicated that whole milling yields of Wells were not as good as other varieties. Two factors that probably contributed to the lower whole milling yields are 1) Wells has not traditionally produced whole milling yields that are consistent as Cocodrie or CL161, and 2) this year there were delays in harvest due to rain that resulted in more stress on the grain.
With the loss of Cheniere in 2007, the majority of Wells was grown on light-textured soil because it has more resistance to straighthead than Cocodrie. One drawback is that Wells does not offer much resistance to blast, which became a problem this year in some locations. As a result, it was made evident this year that producers need a high-yielding variety that has straighthead and blast resistance.
varieties, two hybrids make rec list
Dr. John Saichuk
In 1990, 80 percent of Louisiana’s rice acreage was planted to four varieties – Lemont, Mars, Tebonnet and Mercury. By 2000, our medium grain acreage had declined to less than 10 percent, and 88 percent of our land was in Cypress and Cocodrie. Seventy-five percent of our acres were divided equally between Cocodrie, Cheniere and CL131 in 2006.
It was expected that CL151 would enter the commercial market in 2007 and would displace some of the Cocodrie and Cheniere. The discovery of the adventitious presence of LL601 upset that apple cart. We ended up with 46 percent of our acres in Cocodrie and 15 percent in CL161. Nearly 20 varieties and hybrids were used to fill in the remaining acres with no variety or hybrid occupying even 10 percent of the acres.
This unexpected turn of events forced growers to try varieties or hybrids they might not have tried otherwise.
About 27 percent of the acres were planted to Clearfield lines and 17 percent to hybrids or blends. More acres would likely have been planted to Clearfield varieties had not both CL131 and 151 been pulled from the seed supplies.
The hybrid acreage might have been lower if Cheniere and CL131 had been available.
Our recommendations committee met in October 2007 to determine which varieties would be recommended for 2008 and to make changes to the publication Rice Varieties and Management Tips 2008. That publication is currently available on our Web site at www.lsuagcenter.com/en/crops_livestock/crops/rice/Publications. Hard copies should be available through your local county agent’s office, too.
Ten varieties and two hybrids made the recommended list this year. These are: CL131, CL161, CLXL 730, Cheniere, Cocodrie, Cybonnet, Cypress, Trenasse, Wells, XL 723, Jupiter and Bengal. The last two are medium grain varieties. CL171-AR is not yet recommended because we have not tested it for three years. The same is true of the obviously absent hybrids.
It has been a long-standing policy to only recommend varieties we have had the opportunity to evaluate for three years. This is a conservative policy intended to protect the grower. While some have expressed impatience with the practice, it has proven to be a good insurance policy.
Normally, we do not use a variety in our verification program until it is fully recommended. Last year we made an exception by planting two fields to CL171-AR. It looked good, but we also found out it is very susceptible to sheath blight.
I would not be afraid to plant CL171-AR in 2008, but I would limit the acreage devoted to it until a full recommendation is made. The same can be said of some of the hybrids.
Louisiana’s acreage is expected to be dominated by Cocodrie,
Cheniere, CL131 and an assortment of hybrids. For all practical purposes,
the seed supply should be adequate and free of any adventitious presence
Know the number of seeds per pound
DR. M.O. “Mo” WAY
Variety selection is crucial to producing a successful rice crop. I have heard it said that 50 percent of rice yield potential rests with the variety, and 50 percent rests with the management. So, selecting the proper rice cultivar is like selecting an engine for your truck – you must have the horsepower up front to perform reliably when pulling a heavy load.
In selecting a particular variety, you should look to your own history of production. If you grew a specific variety before, you like that variety and you feel comfortable with it, then go with a proven winner on most of your acreage. However, do not put all of your eggs in one basket – do not plant your entire acreage in a single variety that you have little or no experience with. Instead, plant part of your acreage in the newer varieties and gradually increase that acreage as you become more familiar with these newer varieties.
Obviously, you must take into consideration seed availability, seed
costs and seeding rate recommendations.
This approach is especially true if you plan on ratoon cropping. The ratoon crop is becoming increasingly important – put the same time and management efforts into your ratoon crop as you do your main crop. We no longer can afford to treat the ratoon crop as lagniappe!
A good ratoon crop can yield 1/3 to 1/2 of a main crop. Also, just because you select a cultivar that has resistance to a given disease or insect, don’t assume that you do not need to check this rice for disease or insect pressure. In addition, as always, make sure you buy certified seed, which possesses high purity and germination. Be sure to factor in the germination rate of your seed when determining seeding rates.
For your information, according to the 2007 Texas Rice Crop Survey (which represents about 1/3 of Texas’ rice acreage) Cocodrie made up 49 percent of the planted acreage, Presidio 10 percent, Trenasse nine percent, XL723 eight percent, Jupiter four percent and ClearfieldXL730 two percent. Other planted cultivars were Wells, XL729, Sierra, Milagro and Cybonnet.
To help in cultivar selection, average main crop yields derived from replicated small plot studies conducted at Beaumont and Eagle Lake from 2005 to 2007 are:
Beaumont: XL723 9,758 lb/acre; Cocodrie 8,325 lb/acre; Cybonnet 7,584 lb/acre; Trenasse 7,558 lb/acre; Sabine 7,212 lb/acre; Presidio 7,058 lb/acre and CL161 6,656 lb/acre.
Eagle Lake: XL723 10,369 lb/acre; Trenasse 9,253 lb/acre; Cocodrie 8,934 lb/acre; Cybonnet 8,708 lb/acre; CL161 8,356 lb/acre; Sabine 8,282 lb/acre and Presidio 7,672 lb/acre.
These data were provided by Mike Jund, Dr. Lee Tarpley and Jack Vawter.
Improved Head Rice
Dr. Jim Hill
M-202 has for many years been the backbone of California Calrose types. M-202 had wide adaptability from the cooler areas affected by the Delta breezes to the warmer areas of the northern Sacramento Valley. However, the introduction of M-205 and M-206 has reduced the dominance of M-202 as the industry’s stalwart. Over the last few years, M-202 acreage has dropped from more than 50 percent to about 20 percent while M-205 and M-206 acreage have both gained ground with each now about 20 percent and 30 percent of the acreage respectively. M-104 remains as one of the choices for the cooler areas at about five percent of the acreage.
Why the changes? One very big factor in both M-205 and M-206 is that, while yields are as good as M-202, head rice is on average about two points better and sometimes more. Studies by Jim Thompson and Cass Mutters comparing moisture at harvest in M-202 and M-206 vs. head rice yield show that the latter maintains head rice over a much wider range of harvest moisture. Thus, the penalty for harvesting drier rice is less severe for M-206 than for M-202. Although not part of this research, it appears that M-205 may exhibit similar behavior considering it also shows better head rice.
The geographical adaptation of M-205 and M-206 differ. Carl Johnson, the lead breeder of both M-205 and M-206, places the limits on M-205 to the warmer areas of the State – north of highway 20 and west of highway 70 in the Sacramento Valley and definitely not in the areas affected by the cool Delta breezes.
M-206, however, shows more stability across environments and is one of the reasons it is now the leading variety in California.
One aspect of M-206, as pointed out last year in this column, is its resilience to adverse conditions.
M-206 appears to be better able to bounce back from weather-related or other cultural problems giving it more stability than M-202.
Results of variety trials released
The 2007 growing season conditions were apparently good for rice as the low disease pressure and a dry harvest resulted in good yields. Actually, the yields were higher than seen in previous years as evidenced by another record average. This was true in the state yield trials as well.
The number of rice varieties grown in Missouri in 2007 was limited due to the absence of Cheniere and CL131. Varieties for which there is or was seed available in 2008 include Wells, Francis, Cocodrie, Cybonnet, Trenasse, Jupiter, RiceTec XL723 and RiceTec XP744, as well as Clearfield lines CL161, CL171, RiceTec CL XL745, RiceTec CL XL729 and RiceTec CL XL730, according to the seed company sources.
In the Missouri Rice Variety Trials conducted at the Missouri Rice Research Farm and the University of Missouri Delta Research Center, the top five long grain varieties across locations and soil types were, in order, RiceTec XL723, RiceTec XP744, Wells, Francis and Cocodrie. The best medium grain variety across locations was Jupiter. In a Clearfield trial, the order of varieties by yield was RiceTec CL XL745, RiceTec CL XL729, RiceTec CL XL730 and CL161.
On a clay soil at the UM Delta Center, the best varieties were the same as those across locations; however, Bowman, a new variety developed in Mississippi, performed well. Since some of our rice producers grow rice after rice, in our five years of continuous rice trials we’ve conducted, the RiceTec XL723, RiceTec XP744, Wells, CL171-AR and Trenasse were the top-yielding lines in 2007.
Though water-seeded rice acreage is limited in Missouri, the most promising varieties would be Wells, Francis, RiceTec XL723, Cocodrie and CL171-AR.
Milling quality was apparently good despite the dry growing conditions during seed fill and into harvest. In some cases, the dry conditions negatively impacted selected varieties as the dry harvest progressed through a dry autumn.