Herbicide Resistant Herbicide Resistant Corn Hybrid Corn Hybrid

Performance in Performance in GeorgiaGeorgia

E. P. Prostko, E. F. Eastin, W. K. Vencill,E. P. Prostko, E. F. Eastin, W. K. Vencill,

and R. D. Leeand R. D. Lee

University of GeorgiaUniversity of Georgia

Dept. Crop & Soil SciencesDept. Crop & Soil Sciences

Herbicide-Resistant CropsHerbicide-Resistant CropsThe problem The problem …..…..

OROR

Will anyone buy them????Will anyone buy them????

Herbicide Resistant Crops - US Herbicide Resistant Crops - US 20002000

54

6

26

0

10

20

30

40

50

60

Soybeans Corn Cotton

Crop

% o

f US

Cro

p

Source: NASS, June 2000Source: NASS, June 2000

Herbicide Resistant Corn HybridsHerbicide Resistant Corn HybridsWhat’s Available??What’s Available??

Roundup ReadyRoundup Ready

Liberty LinkLiberty Link

Clearfield Corn**Clearfield Corn**

* * IR or IT IR or IT

** Not a GMO** Not a GMO

Clearfield Corn (IR vs. IT) Clearfield Corn (IR vs. IT) What’s the difference?What’s the difference?

IR Hybrids (IMI-Resistant)IR Hybrids (IMI-Resistant) * both parents carry resistance to IMI’s* both parents carry resistance to IMI’s

* cross-resistant to SU’s (OP interactions, * cross-resistant to SU’s (OP interactions, recrop)recrop)

* harder/slower to develop* harder/slower to develop IT Hybrids (IMI-Tolerant)IT Hybrids (IMI-Tolerant) * * only 1 parent has resistance to IMI’sonly 1 parent has resistance to IMI’s

* easier/faster to develop* easier/faster to develop

Herbicide-Resistant CropsHerbicide-Resistant CropsWhat do producers want/need to know??What do producers want/need to know??

weeds controlledweeds controlled cost/Acost/A yield potentialyield potential yield drag??yield drag??

Herbicide Resistant Corn Herbicide Resistant Corn Hybrid Tests - 2000Hybrid Tests - 2000

3 locations3 locations small plotssmall plots CN, RR, LL, CN, RR, LL,

Clearfield hybridsClearfield hybrids treated/untreatedtreated/untreated 8” tall corn8” tall corn grain yieldgrain yield

ResultsResults

no statistical differences in yieldno statistical differences in yield

no yield loss associated with no yield loss associated with herbicide applicationherbicide application

Clearfield Corn Hybrid Performance in Clearfield Corn Hybrid Performance in Georgia - 2000Georgia - 2000

020

406080

100

120140

P32Z18IR* G8222IT* P32K61

Hybrid

Yie

ld (

% o

f av

erag

e)

Athens Attapulgus Tifton

*Treated with Lightning (1.28 oz/A) + Atrazine (1.5 pt/A) + AMS (2.5 lbs/A) + COC (1% v/v)

Roundup Ready Corn Hybrid Performance Roundup Ready Corn Hybrid Performance in Georgia - 2000in Georgia - 2000

020

406080

100

120140

G8349RR* DK626RR* P32K61

Hybrid

Yie

ld (

% o

f av

erag

e)

Athens Attapulgus Tifton

*Treated with Roundup Ultra (1 qt/A)

Liberty Link Corn Hybrid Performance in Liberty Link Corn Hybrid Performance in Georgia - 2000Georgia - 2000

020

406080

100

120140

G8366BtLL* P32K63LL* P32K61

Hybrid

Yie

ld (

% o

f av

erag

e)

Athens Attapulgus Tifton

*Treated with Liberty (28 ozs/A) + AMS (2.5 lbs/A)

Herbicide Resistant Corn Herbicide Resistant Corn Hybrids in Georgia - 2000Hybrids in Georgia - 2000

hybrids that performed equal to or hybrids that performed equal to or better than the test averages better than the test averages included the following:included the following:

* Pioneer 32K63LL (Liberty)* Pioneer 32K63LL (Liberty)

* Garst 8222IT (Clearfield)* Garst 8222IT (Clearfield) * Dekalb 626RR (Roundup)* Dekalb 626RR (Roundup)

Need more data!!!!!Need more data!!!!!

Herbicide Resistant Corn Hybrid Herbicide Resistant Corn Hybrid TechnologiesTechnologies

Cost/ACost/A

Hybrid Seed Herbicide Total

RR $6.00 $6-8.00 $12-14.00

LL $0.00 $13-19.00 $13-19.00

Clearfield $0.00 $12.61 $12.61

Cost/A for 1 applicationCost/A for 1 application

The use of herbicide resistant The use of herbicide resistant corn hybrid technologies should corn hybrid technologies should be based upon ……………...be based upon ……………...

marketabilitymarketability weed control problemsweed control problems consistent hybrid performance consistent hybrid performance

and other agronomic traitsand other agronomic traits reduced or equal control costsreduced or equal control costs

University ofGeorgia

ExtensionWeed Science

(gaweed.com)