1. Herbicide Resistant Corn Hybrid Performance in Georgia E. P. Prostko, E. F. Eastin, W. K. Vencill, and R. D. Lee and R. D. Lee University of Georgia Dept. Crop & Soil Sciences

2. Herbicide-Resistant Crops The problem ….. OR Will anyone buy them????

3. Herbicide Resistant Crops - US 2000 Source: NASS, June 2000

4. Herbicide Resistant Corn Hybrids What’s Available??  Roundup Ready  Liberty Link  Clearfield Corn** * IR or IT ** Not a GMO

5. Clearfield Corn (IR vs. IT) What’s the difference?  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, recrop) * cross-resistant to SU’s (OP interactions, recrop) * harder/slower to develop * harder/slower to develop  IT Hybrids (IMI-Tolerant) * only 1 parent has resistance to IMI’s * only 1 parent has resistance to IMI’s * easier/faster to develop * easier/faster to develop

6. Herbicide-Resistant Crops What do producers want/need to know??  weeds controlled  cost/A  yield potential  yield drag??

7. Herbicide Resistant Corn Hybrid Tests - 2000  3 locations  small plots  CN, RR, LL, Clearfield hybrids  treated/untreated  8” tall corn  grain yield

8. Results  no statistical differences in yield  no yield loss associated with herbicide application

9. Clearfield Corn Hybrid Performance in Georgia - 2000 *Treated with Lightning (1.28 oz/A) + Atrazine (1.5 pt/A) + AMS (2.5 lbs/A) + COC (1% v/v)

10. Roundup Ready Corn Hybrid Performance in Georgia - 2000 *Treated with Roundup Ultra (1 qt/A)

11. Liberty Link Corn Hybrid Performance in Georgia - 2000 *Treated with Liberty (28 ozs/A) + AMS (2.5 lbs/A)

12. Herbicide Resistant Corn Hybrids in Georgia - 2000  hybrids that performed equal to or better than the test averages included the following: * Pioneer 32K63LL (Liberty) * Garst 8222IT (Clearfield) * Garst 8222IT (Clearfield) * Dekalb 626RR (Roundup) * Dekalb 626RR (Roundup) Need more data!!!!!

13. Herbicide Resistant Corn Hybrid Technologies Cost/A Cost/A for 1 application

14. The use of herbicide resistant corn hybrid technologies should be based upon ……………...  marketability  weed control problems  consistent hybrid performance and other agronomic traits  reduced or equal control costs

15. University of Georgia Extension Weed Science (gaweed.com)