National Jointed Goatgrass Research Program

 

Progress Report-2002

NOTICE
The following is a progress report containing preliminary data and results that may be modified by future research.
Please contact the listed authors
or Extension Coordinator for additional information.

 

1. TITLE: Integrating IMI-resistant wheat into Oklahoma Wheat Production Systems for Jointed Goatgrass Management

2.PERSONNEL: Tom Peeper, Jason Kelley

3. TIME LINE: Began July 2001.  Planned duration -5 years.  We are on schedule.

4. ORIGINAL HYPOTHESIS: Jointed goatgrass (JGG) can be effectively and selectively controlled in hard red winter wheat in the Southern Great Plains by applications of imidazolinone herbicides if wheat is seeded that is tolerant to these herbicides.  Such control would be superior to control obtainable by cultural methods. 

5. SUMMARY OF PROGRESS: The first year cycle of treatments was completed in 2002 as planned.  Beyond herbicide failed to control JGG over 91%, which was too low to search for tolerant or resistant individuals.  Lower than expected control was attributed to late emergence, poor competition from the crop, and drought conditions.  JGG density in the fall of 2002, prior to seeding, was numerically greater in plots treated with Beyond in the spring of 2002 than it was in unsprayed plots moldboard plowed in the fall of 2001, but less than in stubble mulched plots that were not treated with Beyond.

6. OBJECTIVES:  (1) Conduct field research under conditions that expose JGG to pollen from imi-tolerant wheat, and investigate whether JGG x imi-wheat hybrids emerge that are herbicide resistant. (2) Determine the effect of varying degrees of selection pressure, due to varying management systems, on emergence of imi-tolerant JGG biotypes. (3) Use the information obtained above to develop management recommendations designed to perpetuate the usefulness if IMI-tolerance technology.

7. EXPERIMENTAL DESIGN: The experimental design includes 7 replicated (4 reps) treatments.   Variables included in different treatments include tillage system, (conventional or stubble mulch tillage), imi-wheat or conventional wheat, and the timing and frequency of use of Beyond herbicide.  For comparison with conventional methods, one treatment includes BMP’s for management of JGG in conventional wheat, i.e. early maturing competitive cultivar, high seeding rate, narrow rows, and banded started fertilizer.  Another treatment has conventional BMPs alternating with Clearfield wheat and Beyond herbicide application.    At this point, I am very satisfied with our treatment selection and the experimental design.  Alex asked about the moldboard plowing operation.  We used a 3-16 rollover IHC plow mounted on a JD 3020 operated wide open in 3rd gear, giving a plowing speed of about 3.5 MPH less a few % slippage.  The plow was set at 7 to 8 inches deep.  In 2001, the soil was fairly dry and the plow rolled up a lot of clods.  In 2002, moisture was ideal for plowing.  This plow rolls the furrow slice fairly well, rather than standing it on edge.  In 2002, the soil was thrown in the opposite direction that it was in 2001, to avoid getting deep dead furrows on one side of plowed plots.

8. PROGRESS/CONCLUSIONS.  The field research is underway, but there has only been one application of Beyond herbicide to date.  So, we could not expect to have imi-tolerant hybrids in the field until this year at the earliest.  However, we are already learning a lot about how JGG responds to various cultural systems.  First, in October ‘01 the density of JGG seedlings in the conventionally tilled plots (moldboard plowed) was 6 plants/m² versus 29 plants/m² in the stubble-mulched plots. 

We were surprised that the Beyond treatment did not control all of the JGG (visual ratings at harvest of 90 to 91%) despite the fact that it was relatively small (10% 3-leaf, 20% 4-leaf, 50% main stem plus 1-tiller, 20% main stem plus 2 tillers) and was an open target when the herbicide was applied.  On average, we had 745 JGG spikelets per bushel in the grain harvested from Beyond treated plots compared to 3720/bushel in similar plots that did not receive Beyond.  So, Beyond® only reduced JGG spikelets by 80%.  I might point out that we assumed that the MF35 combine might not clean out as good as our plot combines, so we harvested the Beyond treated plots first, then went back and harvested the plots with no herbicide applied.  The combine was completely clean when we started.  This avoided the question of whether the JGG in wheat grain from Beyond-treated plots was just carryover contamination in the combine. 

These results agree with our earlier observations that a dense wheat canopy is often essential to get good weed control with Beyond, and raise more questions in my mind about how consistent this herbicide will be in the drier parts of Oklahoma, where JGG is a bigger problem.  Alex questioned whether we applied the Beyond right.  I suppose that is a logical question when performance isn’t up to par.  The Beyond was applied at 4 fl oz/acre with a tractor mounted sprayer in 19.2 GPA of water with 0.25% v/v AG-98 nonionic surfactant + 1.25% v/v 28-0-0, using Turbo Tee-Jet 11003 tips and 40 psi pressure.  Rainfall for 30 days before treatment totaled 3/10 inches, with the largest event providing 1/10 inch.  So, it was dry.  However, in April, 12 days after treatment, it did rain ½ inch.  The average high temperature for 7 days before spraying was 51 F with a range of 38 to 66 F.  Average low temperature was 29, with a range of 15 to 41 F.  I attribute the relatively poor control to the dry, stressed conditions of the JGG when sprayed.  Alex also asked why we applied Beyond so late.  On March 26, when we applied it, 30% of the wheat was still in the 3 leaf stage.  Only 60% had a tiller.  We get concerned, based on experience about applying Beyond on small wheat, due to injury.

The grain yields were not very high, which was attributed to the relatively late seeding date.  Alex asked why the yields were lower with the Clearfield Jagger than the regular Jagger.  We have to remember that the Clearfield Jagger we are using isn’t a well purified cultivar at all.  It is a bulk population that was increased relatively early in the breeding scheme, but it has yielded well for us in the past.  We know that the TAM 110 genetics in this material is inferior to Jagger, yield wise, for Northcentral Oklahoma.  So, the yield differences should not really be a big surprise, but it is the best wheat available right now.  This material does not appear to be well adapted to late seeding. 

Also, we have seen injury to small wheat from Beyond, and a spring application on small wheat allows very little time for recovery.  I don’t think injury was that much of a factor here, but it would be fair to say that the herbicide certainly didn’t do that little wheat any good.  The conventionally tilled Jagger, seeded at 120 lb/A with banded starter fertilizer (60 lb/A of 18-46-0) in 6-inch rows made 33.9 BU/A.  In contrast, mean yield of the Jagger-CL in stubble mulch tillage, seeded at 60 LB/A, with broadcast fertilizer in 8-inch rows was 18.9 BU/A.  Clearly, banding the P was beneficial to the late seeded wheat.

There was evidence that intensive cultural practices can reduce JGG density.  The stubble-mulched Jagger seeded at 60 LB/A in 8-inch rows with broadcast fertilizer had 6170 JGG spikelets per bushel of harvested wheat. In contrast the moldboard plowed Jagger seeded at 120 LB/A in 6 inch rows with banded starter fertilizer had 2110 JGG spikelets per bushel of harvested grain, which was a reduction of 65%.  On an area basis, intensive cultural practices reduced JGG spikelets collected with the wheat from 160,420/acre to 71,530 /acre.  So, on an area basis, the reduction was 55%.  Conversely, the data also shows that such intensive  cultural practices let a great deal of JGG go to seed.

Plots were examined for hybrids twice, and none were found.  The closest inspection occurred simultaneously to fulfilling a request for 8 samples of JGG per plot from another researcher.  The JGG was relatively small at harvest, and much of it lodged before harvest, thus, it is possible that a few hybrids escaped our observation.

9.PUBLICATIONS: No publications yet

10. TECHNOLOGY TRANSFER ACTIVITIES.  Dr. Case Medlin joined our faculty as State Extension Weed Specialist in late summer of 2001.  His first big project was to set up 8 on-farm demonstrations of Clearfield wheat across the state.  Two of these sites were with jointed goatgrass as the main target.  In addition he has written materials for the County Extension Educators about the use of Clearfield technology for grass control in wheat and presented information at several wheat growers meetings.  This is the first time in 10 years that we can truly say that we now have an effective wheat-weed control extension program.  He has been aggressively developing web-based ID information and control recommendations that should prove very useful.  Our farmers and applicators still have difficulty in distinguishing among the various winter annual grasses that infest our wheat.

You ask for a list of recommendations to producers.  Briefly stated, our basic recommendations for JGG in wheat are (1). Try Clearfield wheat sprayed with Beyond on a trial basis only, because the variety choice is currently very poor for most of Oklahoma, (2) Use intensive cultural practices as we are doing in this project (Moldboard 7 to 8 inches deep, keep subsequent tillage shallow, seed 120 lb/acre of a competitive cultivar in narrow rows with banded started fertilizer, and harvest as soon as possible before the JGG shatters).  and, (3) Consider alternatives to wheat grain production, such as crop rotation , graze-out, or harvesting the wheat for hay when it is feasible. We also stress the importance of clean seed.  Our wheat extension specialist, Gene Krenzer, with whom I have worked closely for several years, has a special project going on right now to demonstrate problems with farmer-saved seed.  He is trying to get our farmers to quit saving contaminated and poor quality seed, and this effort dovetails right in with our weed control efforts.  We plan to show the plots we are working on in this project at our annual field day at the Northcentral Research Station in May.  Last year we didn’t have enough results or data to justify stopping the tour wagons at these plots.

 

Data collection from 5 year jointed goatgrass experiment at Lahoma, Oklahoma

 

 

 

 

 

 

 

 

 

 

 

JGG

plants

Volunteer wheat plts

JGG

plants

Volunteer wheat plts

Visual JGG Control

Wheat

Yield

Wheat

moisture

Wheat

test wt

Jgg

dockage

Jgg spikelets in 200 grams

 

1/4M2

1/4M2

1/4m2

1/4M2

percent

bu/ac

percent

lbs/bu

percent

of grain

Treatment

Oct 01

Oct 01

Oct 02

Oct 02

6-24-02

6-24-02

June 02

June 02

June 02

June 02

1

0.8

0.8

1.9

0.5

13

33.9

9.1

54.8

0.19

15.5

2

3.5

0.8

30.1

3.9

0

21.0

9.2

52.4

0.39

27.3

3

5.5

4.0

19.0

2.4

91

16.1

9.1

51.5

0.09

 7.3

4

8.8

1.3

14.3

3.9

90

20.6

9.0

52

0.06

 4.8

5

14.8

1.0

18.3

2.4

90

17.8

8.9

51.9

0.06

 4.3

6

5.3

2.3

47.1

12.5

0

26.0

9.7

51.8

0.69

45.3

7

1.8

0

4.1

0.6

18

25.3

9.0

53.4

0.43

31.3

LSD 0.05

NSD

1.7

15.4

NSD

11.1

9.2

0.5

2.3

0.28

18.2

Treatment 1: Conventional tillage, competitive traditional wheat, high seeding rate, narrow row spacing, banded starter fertilizer and no herbicide any year 

Treatment 2:Stubble mulch tillage, Clearfield wheat, normal seeding practices, and no herbicide any year

Treatment 3:Stubble mulch tillage, Clearfield wheat, normal seeding practices, and Beyond applied each year at 4 fl oz/acre

Treatment 4:Stubble mulch tillage, Clearfield wheat, normal seeding practices, sprayed with Beyond at 4 fl oz/acre in 2001-2002, 2002-2003, and 2003-2004.  In 2004-2005 and 2005-2006 traditional wheat with no herbicides

Treatment 5:Stubble mulch tillage, Clearfield wheat, normal seeding practices, sprayed with Beyond at 4 fl oz/acre in 2001-2002 and 2002-2003.  In 2003-2004, 2004-2005, and 2005-2006, traditional wheat with no herbicides

Treatment 6:Stubble mulch tillage, traditional wheat and seeding practices in 2001-2002, 2003-2004, and 2005-2006 with no herbicides, Clearfield wheat in 2002-2003 and 2004-2005 sprayed with Beyond at 4 fl oz/acre

Treatment 7:Conventional tillage, competitive traditional wheat, high seeding rate, narrow row spacing in 2001-2002, 2003-2004, and 2005-2006.  Clearfield wheat in 2002-2003 and 2004-2005 with high seeding rate, narrow row spacing and no herbicides

National Jointed Goatgrass Research Program

Home  |  Background  |  Research  |  Management  |  Publications  |  FAQs  |  Citation List  |  Links
Contacts  |  Site Map  |  Search


Please submit website comments and questions to Doug Schmale

Copyright © 1994-2006.
National Jointed Goatgrass Research Program

www.jointedgoatgrass.org
Host
ing Provided by Kansas State University

Disclaimer  |  Nondiscrimination Statement