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Operating under the
authority of the Secretary
of Food & Agriculture,
State of California

Dana Dickey, Manager
PO Box 507
Yuba City, CA 95992
Phone: 530-673-6247
Fax: 530-674-0426

Issue #6, Spring 2000

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Interesting Combinations

    Dr. Albert Fisher has been doing active research on weed control for the Rice Research Board for several years now. One of the directions he is exploring is combinations of chemicals. One of the interesting ones is embodied in Duet®, a combination of propanil and bensulfuron (Londax®). Duet is not currently available in California, but a tank mix of the components is allowable and has been tested successfully by others. (You should note that the UC tests have been run only one year and are definitely preliminary. This is not a UC recommendation, just a report of findings that may encourage you to try a small experiment of your own).
    Duet® was tested at two different rates. A 4 quart/ac (4 quarts propanil plus 1.25 oz. of bensulfuron (0.82 oz. a.i.)) and 6 quart/ac rate (6 quarts propanil plus 2.1 oz. of bensulfuron (1.25 oz. a.i.)). Application occurred at the 4 leaf stage of rice and the 2 tiller stage. In the accompanying chart you will see the results compared with the 4 and 6 quart rates of propanil alone. As a further standard, molinate (Ordram®) followed by bensulfuron (Londax®) is shown as a comparison. All treatments were applied with the adjuvant crop oil concentrate (1.25% v/v). In the Duet® and propanil alone treatments, water was completely drained for application to expose weed foliage, and returned 24 hours later.




Percent Control

Treatment propanil bensul
timing   Wg St Rb Ds Sf yield
Duet® 4 qt 1.25 oz 4 leaf   83 60 100 98 100 7470
Propanil alone 4 qt 0 4 leaf   68 63 83 97 100 7390
Duet® 4 qt 1.25 oz 2 tiller   90 92 97 83 100 7900
Propanil alone 4 qt 0 2 tiller   88 33 100 98 100 7540
Molinate followed by Londax 0 1.25 oz 2 tiller   100 100 100 100 100 8620
Duet® 6 qt 2.1 oz 4 leaf   93 43 100 100 100 8060
Propanil alone 6 qt 0 4 leaf   77 63 90 97 100 8000
Duet® 6 qt 2.1 oz 2 tiller   95 90 100 100 100 8420
Propanil alone 6 qt 0 2 tiller   92 83 100 100 100 7850
Molinate followed by Londax 0 2.1 oz 2 tiller   100 100 100 100 100 8100
Wg = watergrass    St = sprangletop     Rb = ricefield bulrush    Ds = ducksalad     Sf = smallflower umbrellaplant

    The high rate of Duet®, at both early and late timings, resulted in better weed control and yields than the propanil applications at the same rate and timings. Crop injury with Duet® was low. Both the Duet® and propanil treatments were fairly effective on most weeds, but tended to miss sprangletop.
    In its first year of testing Duet® has demonstrated good broad-spectrum weed control, while proving to be a safe herbicide for rice. The presence of bensulfuron enhances watergrass control compared to the equivalent rates of propanil alone.

Distinguished Achievement

    On December 15, 1999, Dr. James Hill was honored as the 1999 recipient of the James H. Meyer Distinguished Achievement Award. This award recognized the tremendous contribution of Dr. Hill as an extension agronomist, who has worked with the rice industry since 1980. At present, Dr. Hill is on a three-year leave of absence at the International Rice Research Institute in the Philippines, where he is leading the Institute’s global programs on irrigated rice.

Where are they?

    At the beginning of 1999 four new rice varieties were released. This year, two medium-grain varieties, M-205 and M-104 were released. Anyone wondering where they are? Since the Rice Research Board puts a considerable portion of your funds into breeding new varieties, I want to give you a view of the process.
    Breeders begin the process by cross pollinating lines they feel have promise or might combine interesting characteristics. (These lines have often taken years to develop through crossing and backcrossing or introducing varieties from foreign sources). Over 800 such crosses are made each year in the greenhouse, some in early spring for planting at Biggs, some in summer for planting in the Hawaii Winter Nursery. Seed from the crosses is planted and individual panicles from the succeeding generation selected and advanced. The Rice Experiment Station (RES) breeding nursery annually contains 70,000 short rows of “children” at various stages. Each year these progeny rows are tested and a fraction of them planted for the next generation. As each generation is grown, rice naturally self-pollinates and more of the genes become “fixed”, making the line uniform and allowing it to breed true (after about 10 generations).
wpeF.jpg (15505 bytes)    As you might guess, the breeders work to select the best of the “children” and reject an enormous number of sub-standard lines. This winnowing process continues for several years — selecting, purifying, and advancing to the next generation. After about five generations, roughly 2500 outstanding selections from different crosses are grown in Small Plot Yield Tests ( SPYT). This step eliminates even more lines and gives about 500 lines to start Large Plot Yield Tests (LPYT). The breeders select their most promising lines to include in the state-wide yield tests. Approximately 100 lines now leave the station for testing in different rice growing areas for the next several years.
    Less than 30 experimental lines reach the stage of growing headrows for seed increase and quality assessment. After further evaluation, only a handful of these will make it to the headrow, breeder, and foundation seed increase stage. You can see that a new variety is literally “one in a million”. The Board of Directors at the RES review multiple years of data gathered from the statewide yield tests and the breeders recommendations before deciding to release a variety. If they release the variety, it is presented to the California Crop Improvement Association (CCIA) for review, approval, and release in the certified seed program.
    When a variety gains approval for release, the RES sells seed (allocated by CCIA) to interested California seed growers to expand the amount of seed available. It will usually take two years to expand the seed supply so that it is widely available to rice growers as certified seed. Meanwhile, the RES continues to produce a pure line of seed through its headrow, breeder, and foundation seed programs.
    Although this has been a whirlwind tour of the process, I hope this helps clarify the reason the RRB supports the long-term process of bringing about new varieties. It takes a long time to properly purify, test, and verify a variety before it is delivered to you.

RRB Web Site

    The Rice Research Board has a web site up and running that I hope will benefit you. The main purpose of the site is to eventually have a place where you can access all of the annual reports. The reports are indexed by year and by topic — so you can find the 1995 report, or look up “Chemicals/Furadan” or “Disease/Blast”.
    Additional information you may find interesting is contained under Newsletters and Weather. The Weather selection allows you to examine weather data from the 13 RRB weather stations scattered around the Sacramento Valley. The temperature, wind, humidity, and rainfall readings are updated hourly. Color pictures are a feature of the Newsletter section that are not available in the printed versions. See what we have to offer at www.syix.com/rrb

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