1. Experience Using GEM Germplasm in a Public Breeding Program Jim Hawk, Tecle Weldekidan, and Travis Frey Department of Plant and Soil Sciences

2. GEM Objectives To improve and broaden the germplasm base Traits targeted are agronomic productivity, disease and insect resistance, and value-added The ultimate target is to release lines for applied and basic research

3. Topics for Discussion 1.Choice of parental germplasm 2.Breeding methods/strategies 3.Hybrid evaluation 4.Opportunities/challenges 5.Summary

4. Choice of Parental Germplasm

5. Breeding crosses- accession x elite inbred line Elite inbred lines- all lines not more than one breeding cycle removed from a commercial product Over 550 breeding crosses – which ones should receive priority for pre- breeding? Other accessions ?

6. Breeding Cross Evaluations Locations: USDA – GEM, Ames – Mike Blanco Golden Harvest, IL – Kevin Montgomery University of Delaware, Newark, DE No. of Breeding Crosses Evaluated: 2003 – 168 2004 – 173

7. Traits Evaluated in Breeding Crosses Adaptability Days to flowering Ear and plant height Ear traits Disease and insect resistance Root and stalk lodging Stay green Plant appearance

8. Recommended GEM Breeding Populations Evaluated at Three Locations, 2003

9. Breeding Crosses Utilized at the University of Delaware ~10/year Most 75% corn belt, some 50% Grow ~1200 plants/population Self 400-600 plants/population

10. Breeding Methodology Pedigree Mass selection for more heritable traits - plant and ear height - maturity - ear traits - disease and insect resistance - root and stalk strength Balance offensive and defensive traits

11. Number of S 1 Ears Selected from GEM Breeding Crosses

12. Breeding Methodology Select 0-160 S 1 ears/breeding cross S 1 families  6-8/family Family and mass selection for more heritable traits Sampling within best S 1 families – 1-3 S 2 ears Goal – 50 S 2 ears minimum from better populations Discard poor breeding crosses

13. Number of SS S 2 Lines Selected from GEM S 1 Families

14. Number of Non-SS S 2 Lines Selected from GEM S 1 Families

15. Hybrid Evaluation ~50 S 2 testcrosses + 3 commercial checks Use testers with good GCA and agronomics (roots, stalks, disease and insect resistance) Locations/reps: 3 DE (1 dryland, 2 irrigated) with 2 reps/location, USDA- GEM Ames-1 rep Second year YT- 2 testers x 8 locations

16. DK212T:N11a10 Lines Crossed to Pioneer SS Tester

17. CUBA164 Lines Crossed to LH185

18. Opportunities/Challenges Trait improvement using selected GEM lines - Grain quality, disease, insect resistance, etc. Use additional testers

19. Opportunities/Challenges Sister line mapping studies – DKXL212:N11a-365-1-1-2-1-1(DE4) DKXL212:N11a-365-1-1-1-1 Recycling - Further improvements needed for commercialization

20. DE4 Recycled Lines Crossed to LH244

21. Summary Focus on adaptability, agronomics, disease/insect resistance first - Breeding cross evaluations - Family and mass selection for more heritable traits May be useful to re-evaluate better breeding crosses in additional years

22. Summary Germplasm for new breeding crosses - Lines, improved populations etc. Useful genetic variation within adapted GEM families

23. Summary Practice art of plant breeding Better to discard earlier than later Focus on better germplasm Plant breeders: Short-term pessimists and Long-term optimists

24. Acknowledgements Wilfredo Salhuana USDA-GEM, Ames Holden’s Foundation Seeds Mycogen Seeds Pioneer Hi-Bred Int.