|Hawk, J - UNIVERSITY OF DELAWARE|
|Jumbo, M - UNIVERSITY OF DELAWARE|
|Weldekidan, T - UNIVERSITY OF DELAWARE|
Submitted to: Illinois Corn Breeders School Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 16, 2008
Publication Date: March 10, 2008
Citation: Hawk, J., Jumbo, M., Weldekidan, T., Holland, J.B. 2008. Comparison of Conventional, Modified Single Seed Descent, and Double Haploid Breeding Methods for Maize Inbred Line Development Using GEM Breeding Crosses. Illinois Corn Breeders School Proceedings. 44: 16-25. Interpretive Summary: The genetic base of the US corn crop is narrow relative to the genetic variability available worldwide for the species. The Germplasm Enhancement of Maize project attempts to diversify the genetic base of US corn by crossing tropical corns to elite US breeding lines. In this study we investigated the effects of different breeding methods on gains from selection in three different GEM crosses. In general, the different selection methods did not produce substantially different results, but one method, the doubled haploid method, appeared to have some small advantage. This may have been because selection for drier ears was practiced on the lines before they were evaluated for hybrid yield potential. Some superior lines were identified from each method, indicating the value of the GEM program for corn breeding in the USA.
Technical Abstract: Good choice of germplasm, breeding methods, and careful evaluation are essential for maize inbred line and hybrid development. Choice of germplasm is particularly important since it may limit genetic gain given even the best breeding methodology and selection strategies. Exotic germplasm has the potential to improve our crop species given advances in transgenic technologies and marker assisted selection, which facilitate precise introgression of economically important exotic alleles. We compared the effects of four breeding methods (Conventional Mass (CM), Conventional GEM (CG), Modified Single Seed Descent (MSSD), and Doubled Haploid (DH)) on the response to selection in three GEM cross populations. Differences between the methods were small, but it appeared that there was some advantage to the DH method, in part because ears were selected for rapid dry-down before testcross yield evaluations. Some superior lines were identified from each method, indicating the value of the GEM program for corn breeding in the USA.