Ohio Wesleyan University, University of Minnesota, University of California (Riverside).
Plant Evolution & Systematics.
My area of focus is the contribution of genetics to understanding plant evolution and systematics. Topics that I have investigated have been the genetics of species differences in plants and the genetics underlying specific traits. A secondary thrust of my work is the application of genetic markers in systematics and evolution. These efforts are oriented towards strengthening taxonomic and phylogenetic decisions and providing detailed insights into patterns of diversification, both in natural systems and domesticated crops. Specific research projects over the past several years have been on speciation and diversity in the Hawaiian daisy (Tetramolopium; Asteraceae), chromosome evolution in the Cyperales, the genetics of traits in crop and their relatives, and population genetics of the California Bay tree (Umbellularia californica), the main foliar host for the organism that causes Sudden Oak Death in California.
Roalson, E. H., A. G. McCubbin, and R. Whitkus. In press. Chromosome evolution in the Cyperales. J. T. Columbus, J. T., E. A. Friar, C. W. Hamilton, J. M. Porter, L. M. Prince, and M. G. Simpson [eds.]. Monocots: Comparative Biology and Evolution. 2 vols. Rancho Santa Ana Botanic Garden , Claremont CA , USA .
Lowrey, T. K., R. Whitkus, W. R. Sykes. 2005. A new species of Tetramolopium (Asteraceae) from Mitiaro, Cook Islands : Biogeography, phylogenetic relationships, and dispersal. Systematic Botany 30:448-455.
Lukaszewski, A. J., K. Rybka, V. Korzum, S. V. Malyshev, B. Lapinski and R. Whitkus. 2004. Genetic and physical mapping of homoelogous recombination points involving wheat chromosome 2B and rye chromosome 2R. Genome 47: 36-45.
Ehdaie, R. Whitkus, and J. G. Waines. 2003. Root biomass, water-use efficiency and performance of wheat-rye translocations of chromosomes 1 and 2 in Spring bread wheat Pavon. Crop Science 43:710-717.
Georgiady, M. S., R. Whitkus, and E. M. Lord. 2002. Genetic analysis of traits distinguishing outcrossing and self-pollinating forms of currant tomato, Lycopersiconpimpinellifolium (Jusl.) Mill. Genetics 161:333-344.
Whitkus, R., H. Doan, and T. K. Lowrey. 2000. Genetics of adaptive radiation in Hawaiian species of Tetramolopium (Asteraceae). III. Evolutionary genetics of sex expression. Heredity 85:37-42.
Plant Taxonomy; Plant Biology; Systematics; Speciation; Diversity, Structure & Function; Biological Inquiry.