Submitted to: International Cotton Genome Initiative Workshop
Publication Type: Abstract Only
Publication Acceptance Date: October 10, 2004
Publication Date: October 10, 2004
Citation: Ulloa, M., Stewart, J.M., Park, Y., Frelichowski, J.E. 2004. Evaluation of germplasm with microsatellites. International Cotton Genome Initiative Workshop. p. 95.
Diversity and relationships based on morphological phylogenetic studies tend to provide poor differentiation among taxa and/or germplasm, making potentially important germplasm accessions from the primary and secondary gene pools almost impossible to recognize as useful genetic resources for cotton breeding. Microsatellites are useful for estimating genetic relationships among collections comprising different taxonomic levels, and for analyzing speciation. A set of selected genomic and EST microsatellites were used to examine the origin of allelic diversity in tetraploid cottons, and to assess recently collected diploid and tetraploid cotton germplasm. Amplification of microsatellites via PCR yielded both monomorphic and polymorphic DNA fragments among New World allotetraploid cottons AD1 and AD2 (G. hirsutum and G. barbadense), the two Asian-African progenitor diploid genomes A1 and A2 (G. herbaceum and G. arboreum), and 12 accessions of D-genome species representing all taxonomic subsections of subgenus Houzingenia. Estimates of genetic similarities among all taxa showed extensive allelic diversity in the D genome. Phenetic trees (N-J, Jackknife, BootStrap, and UPGMA) based on genetic similarities, as measured by microsatellite diversity, produced clades consistent with current taxonomic species delineations. However, the topology of the consensus tree also revealed clades that suggest additional undocumented relationships within the D genome.