Breeding Organic Corn varieties to resist GMO contamination

Breeding Organic Corn varieties to resist GMO contamination

Summary

Backcross generation two (BC2) of adapted elite white and yellow grain parental lines of corn with the cross-sterility gene GA1-S, were back-crossed to the elite parent. Individual plants chosen to backcross were also tested for the presence of the GA1-S allele by crossing to a homozygous GA1-S tester line. If the testcross did not produce seed on the GA1-S tester plant, seed from the backcross (BC3) was discarded. This testcross procedure insured that plants chosen to advance carried the GA1-S allele.

Objectives/Performance Targets

BC1 lines with the cross sterility allele GA1S were backcrossed to the elite parent. The following backcrosses were made between elite Tennessee parent corn lines and cross sterility lines:
1. [(T175 x MO502 GA1-S) x T175] x T175
2. [(T175 x MO511 GA1-S) x T175] x T175
3. [(T177 x MO501 GA1-S) x T177] x T177
4. [(T177 x MO506 GA1-S) x T177] x T177
5. [(T177 x MO508 GA1-S) x T177] x T177
6. [(T274 x MO501 GA1-S) x T274] x T274
7. [(T274 x MO506 GA1-S) x T274] x T274
8. [(T274 x MO508 GA1-S) x T274] x T274
9. [(T276 x MO502 GA1-S) x T276] x T276
Seed harvested from the above crosses contains 87.5% elite adapted germplasm and the the GA1-S allele. Seed from these crosses was grown in a winter nursery in Homestead, FL. The following elite adapted lines with the GA1-S allele were self-pollinated:
1. [(T175 x MO502 GA1-S) x T175] x T175
2. [(T175 x MO511 GA1-S) x T175] x T175
3. [(T177 x MO501 GA1-S) x T177] x T177
4. [(T177 x MO506 GA1-S) x T177] x T177
5. [(T177 x MO508 GA1-S) x T177] x T177
6. [(T274 x MO501 GA1-S) x T274] x T274
7. [(T274 x MO506 GA1-S) x T274] x T274
8. [(T274 x MO508 GA1-S) x T274] x T274
9. [(T276 x MO502 GA1-S) x T276] x T276
Seed harvested from these plants well be grown in the 2014 summer nursery. Individual plants in each line will be hand pollinated with pollen from a red grain tester that does not contain the GA1-S allele. These plants will be self-pollinated the following day. At harvest, ears which contain red seeds will be discarded, and ears that are either completely white (elite adapted lines T175 and T177) or completely yellow (elite adapted lines T274 and T276) will be selected for advance. Seed from these self-pollinations will be 93.75 % homozygous and will be homozygous for the GA1-S allele.

Accomplishments/Milestones

Crosses and backcrosses to the recurrent parent have been completed, producing lines with 87.5% adapted recurrent parent genes and the cross sterility gene. Elite adapted lines homozygous for the cross sterility gene GA1-S will be selected in the summer nursery in Knoxville, TN, during the 2014 growing season. Seed from these these lines will be grown in a winter nursery in FL to increase seed quantity. These lines will then be crossed to produce experimental hybrids for field testing in 2015.

Impacts and Contributions/Outcomes

Successful completion of this research will result in white and yellow grained maize hybrids that cannot be pollinated by genetically modified (GMO) maize hybrids grown in adjacent or the same field. This will prevent loss of income from “adventitious presence” of GMO grain in fields planted to non-GMO cross sterility maize hybrids.

Collaborators: