College of Agricultural Sciences

R. Contreras and Ranney, T. G., “New opportunities for breeding fragrant rhododendrons”, Journal of American Rhododendron Society, vol. 62, no. 4, 2008.

K. Shearer-Lattier and Contreras, R., “Non-targeted mutagenesis of Galtonia candicans by exposing seeds to EMS”. 2014.

K. S. lattier and Contreras, R., “Non-targeted mutagenesis of Galtonia candicans Decne. through exposure to ethyl methanesulfonate”, Combined Proceedings of the International Plant Propagators' Society 65. 2015.

R. Contreras and Friddle, M. W., “‘Oregon Snowflake’ Flowering Currant”, HORTSCIENCE , vol. 50, no. 3, 2015.

R. Contreras, “Ornamental Plant Breeding at Oregon State University”, Combined Proceedings of the International Plant Propagators' Society 63. 2014.

R. Contreras and Ruter, J. M., “An oryzalin induced polyploidy from a hybrid of Hibiscus acetosella x H. radiatus(Malvaceae) exhibits reduced fertility and altered morphology”. 2009.

R. Contreras, Ruter, J., and Hanna, W., “An Oryzalin-induced Autoallooctoploid of Hibiscus acetosella ‘Panama Red’”, Journal of American Horticultural Science, vol. 134, no. 5, 2009.

R. Contreras, Ruter, J., and Schwartz, B. M., “Oryzalin-induced Tetraploidy in Cryptomeria japonica (Cupressaceae)”, HortScience, vol. 45, no. 2, 2010.

K. Shearer-Lattier and Contreras, R., “Penstemon breeding in the Willamette Valley: A lesson in flexibility”, Bulletin of the American Pestemon Society, 2015.

J. D. Lattier and Contreras, R., “Ploidy and Genome Size in Lilac Species, Cultivars, and Interploid Hybrids”, Journal of the American Society for Horticultural Science, vol. 142, no. 5, pp. 355 - 366, 2017.

J. J. Rothleutner, Friddle, M. W., and Contreras, R., “Ploidy Levels, Relative Genome Sizes, and Base Pair Composition in Cotoneaster”, Journal of the American Society for Horticultural Science, vol. 141, no. 5, pp. 457 - 466, 2016.

T. Einhorn, Gibeaut, D., Contreras, R., and Whiting, M. David, “Polyploidy of cells in sweet cherry fruit”. 2012.

R. Contreras and Ruter, J. M., “Preliminary efforts to induce polyploidy in Cryptomeria japonica.”, Proc. 53rd Ann. SNA Res. Conf., vol. 53:159-161. 2008.

R. Contreras, Friddle, M. W., and Lattier, J. D., “Relative fertility and ploidy levels of selected rose of sharon cultivars”, Proc. 58th Ann. SNA Res. Conf., vol. 58:232-236. 2013.

R. Contreras and Ranney, T. G., “Reproductive behavior of diploid and allotetraploid azaleodendrons”. 2006.

R. Contreras, Ranney, T. G., and Tallury, S. P., “Reproductive behavior of diploid and allotetraploid Rhododendron L. ‘Fragrant Affinity’”, HortScience, vol. 42, no. 1, 2007.

J. J. Rothleutner, Contreras, R., Stockwell, V., and Owen, J. S., “Screening Cotoneaster for Resistance to Fire Blight by Artificial Inoculation”, HortScience, vol. 49, no. 12, 2014.

R. Contreras, “A Simple Chromosome Doubling Technique Is Effective for Three Species of Cupressaceae”, HortScience, vol. 47, no. 6, pp. 712-714, 2012.

R. Contreras and Ruter, J., “Sulfuric acid scarification of Callicarpa americana L. (Lamiaceae) seeds improves germination”, Native Plants Journal, vol. 10, no. 3, 2009.

R. Contreras, Ranney, T. G., Tallury, S. P., and Milla-Lewis, S. R., “Using molecular markers to investigate parentage of azaleodendron hybrids.”, Proc. 50th Ann. SNA Res. Conf., vol. 50:632-635. 2005.

J. J. Rothleutner and Contreras, R., “Variable Fire Blight Resistance Among 31 species of Cotoneaster”. 2012.

J. D. Lattier, Chen, H., and Contreras, R., “Variation in genome size, ploidy, stomata, and rDNA signals in althea (Hibiscus syriacus L.)”, Hort. Res., Submitted.

E. Tomasino and Contreras, R., “Volatile analysis of three Philadelphus L. parents and resulting progeny.”, HortScience, Submitted.