Author
 |
Willmot, David |
|
Pollak, Linda |
|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 11/3/2003 Publication Date: 11/3/2003 Citation: Willmot, D.B., Pollak, L.M. 2003. Molecular marker analysis of exotic maize introgression after selection [abstract]. ASA-CSSA-SSSA Annual Meeting. Paper No. C08-Willmot558711-Oral. Interpretive Summary: Technical Abstract: The major goal of the Germplasm Enhancement of Maize project (GEM) is to introgress exotic germplasm into elite U.S. Cornbelt inbred backgrounds to ensure continued genetic gain for yield, etc. An ongoing question has been what percentage of the resultant selections' genetic composition is from the exotic donor compared to the 25% or 50% by pedigree. Secondly, it would be useful to determine if certain loci are skewed toward one parent to highlight regions that may be key to fitness. Nine or 10 of the top lines for yield/moisture from 10 of the best pedigrees were genotyped with 136 SSRs. Sixteen plants of each exotic land-race donor were genotyped to determine their allelic array. DNA of all but three of the elite domestic inbreds were obtained. An ABI 3100 capillary electrophoresis genetic analyzer was used to determine precise band sizes. Alleles in the derived lines were assigned to the exotic or domestic if there was no overlap in band sizes, leaving an average of 62 SSRs scorable for a given pedigree. Among all of the pedigrees, an average of 7.2 loci were skewed toward the domestic parent and 5.9 toward the exotic. The average contribution from the exotic parents was 41% from two-way crosses and 20% from the crosses that were 25% exotic by pedigree. The results indicate that parental selection was effective, but that some SSR loci may be relatively neutral for fitness. |
