Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2007
Publication Date: 8/1/2007
Citation: Johnson, R.C., Kisha, T.J., Evans, M.A. 2007. Characterizing Safflower Germplasm with AFLP Molecular Markers. Crop Science. 47:1728-1736. Interpretive Summary: We showed that AFLP markers distinguished safflower populations and regions in a way consistent with our expectations. Thus, AFLP markers will have numerous applications in germplasm characterization, management and development of safflower genetic resources. These uses include the identification of outliers or unique germplasm, duplicate accessions, collection deficiencies and needs, and determining within and among population diversity. AFLP markers will also be useful for molecular mapping of desired traits for marker assisted selection. Nevertheless, since molecular marker and phenotypic data were only weakly correlated, marker data in safflower should be balanced with phenotypic data whenever possible to give a more complete picture of overall diversity.
Technical Abstract: Characterization of safflower (Carthamus tinctorius L.) germplasm with molecular markers is needed to enhance germplasm management and utilization. Amplified Fragment Length Polymorphism (AFLP) analysis was completed in safflower using two selective primer pairs resulting in 102 unambiguous polymorphic markers. Pairwise distances, the proportion of unmatched markers between entry pairs, were calculated for eight diverse populations of 12 plants each, and on bulked leaf tissue of 96 accessions. The 96 accessions represented seven world regions (the Americas, China, E. Africa, E. Europe, the Mediterranean, S.C. Asia, and S.W. Asia). A bootstrap procedure was used to compare mean distances within populations and regions. Distances within populations, a measurement of population diversity, ranged from 0.005 for PI 544006 to 0.315 for the Arizona Wild Composite (AWC) and differed in 22 of 28 possible comparisons. AFLP variation confirmed our expectation that variation within the AWC would be high, especially when compared to the cultivar Girard with a 0.015 mean distance. Cluster analysis showed that markers resulting from bulked leaf tissue always grouped with the individual plants from a given accessions, so bulked leaf analysis accurately represented overall accession diversity. Regions differed at P<0.05 in all pairwise comparisons showing that AFLP markers distinguished safflower diversity across broad geographic groups. Correlation of the AFLP distance matrix with a phenotypic data matrix with 16 attributes consisting of oil, meal, and growth characteristics was significant at r = 0.117 (P<0.05), but explained only 1.4% of the variation. This weak correspondence between AFLP and phenotypic variation showed that both should be used to fully characterize safflower diversity. AFLP markers were useful for characterizing diversity in safflower, and will be valuable for germplasm management and potentially for mapping desired traits in safflower.