Wednesday, November 15, 2006

Detection of Donor QTL Alleles in Illinois Low Protein for Enhanced Starch Levels and Ethanol Production Efficiency.

H. Sofia Silva, Univ of Illinois, AW-101 Turner Hall, 1102 S. Goodwin Ave, Urbana, IL 61801 and Torbert Rocheford, AW-101 Turner Hall, 1102 S Goodwin Ave, Urbana, IL 61801.

There is interest in modifying levels of protein, oil and starch on maize grain for specific end uses. An example is breeding for higher levels of starch to enhance starch fermentation efficiency to produce ethanol. QTL associated with kernel composition traits would facilitate the development of maize inbreds and hybrids with desirable levels of components enabling a better and more efficient conversion to secondary products. Protein, starch, oil, and kernel weight were measured on grain samples harvested from two replications of a backcross population in five environments. By evaluating in a (ILP×B73)B73 background we are assessing for donor alleles that would improve inbreds and hybrids for increased starch. A molecular map with 144 markers was used to detect QTL associated with kernel weight, protein, oil and starch concentration. Using CIM, ten QTL identified for starch in bins 1.03, 1.05, 1.07, 1.11, 2.08, 3.06, 5.04, 6.01, 6.05 and 9.03; eleven QTL were identified for protein in bins 1.03, 1.05, 1.07, 1.11, 2.03, 2.08, 4.08, 6.01, 6.05, 8.02 and 8.05; six QTL were identified for oil in bins 1.05, 1.11, 2.04, 5.04, 6.00 and 9.04; and eleven QTL were identified for kernel weight in bins 1.05, 1.06, 1.08, 2.04, 3.03, 3.04, 3.06, 4.09, 5.07 and  7.03. The QTL explained 38.3%, 40.2%, 34.2%, and 40.4% of the total phenotypic variation for starch, protein, oil, and kernel weight, respectively. Most alleles for higher starch came from ILP which has higher starch concentration than B73. Most QTL alleles for higher protein came from B73. Five of ten QTL associated with starch concentration were also significant for protein. Two QTL identified for starch were also significantly associated with oil concentration. QTL do not appear to map to starch structural biosynthetic genes, suggesting unknown regulatory loci may influence quantitative variation for starch concentration.