Plant & Animal Genome VI Conference Plant & Animal Genome VI Conference
P82
Brent Barrett, Washington State University, Dept. of Crop and Soil Sciences, 201 Johnson Hall, Pullman, WA 99164-6420
Evaluating genetic diversity among regionally adapted germplasm may expedite crop improvement. The objectives of this study were to i) use amplified fragment length polymorphisms (AFLPs) to assess genetic diversity among wheat (Triticum aestivum L.) cultivars adapted to the U.S. Pacific Northwest, ii) compare AFLP-based genetic diversity estimates (GDEAFLPs) for hypermethylated and hypomethylated portions of the wheat genome, and iii) compare GDEAFLP and pedigree-based diversity (GDEPED) data. Fifty-four spring or winter wheat cultivars were evaluated. Eight PstI:MseI (methylation sensitive) and 8 EcoRI:MseI (methylation insensitive) primer pairs generated a total of 111 and 118 polymorphic bands, respectively. Ordination and cluster analyses, and the analysis of molecular variance, indicated diversity among these cultivars is hierarchically arranged, with the highest diversity levels between spring and winter growth habit types, intermediate levels between cultivars from different market classes within growth habit, and the lowest diversity levels among cultivars within market class. The mean PstI-based diversity estimate was lower than the EcoRI-based estimate (0.51 vs. 0.58, p<0.0001), suggesting methylated regions of the wheat genome are more diverse than unmethylated regions. Comprehensive pedigree information for a subset of 45 cultivars was used to calculate GDEPED (1-Coefficient of Parentage) values. Mean GDEPED was 0.96, contrasting with the GDEAFLP mean of 0.54. Eighty-nine percent of the GDEPED values indicated <10% of the DNA in cultivars under consideration was identical by descent. In contrast, <88% of AFLP fragments were monomorphic. Correlation between GDEPED and GDEAFLP was moderate (rs=0.40, p<0.001). GDEAFLP may more accurately reflect the level of allelic variation among genotypes than GDEPED.