From 1958 to 1971 he was a professor of botany at the University of Kansas, where in 1969 he was appointed chair of the botany department.[3] There he was also the chair of the interdepartmental Ph.D. program in genetics.[1] In 1971 Jackson become the chair of the department of biological sciences at Texas Tech University. There he resigned as chair in 1978, was appointed Paul Whitfield Horn Professor in 1980, became professor emeritus in 1997, and continued his research as Horn Professor Emeritus until he died in 2008.[1]
Jackson collected plants in the United States and Mexico. He began his Mexican collections in 1957 and continued through the 1970s.[2] In the 1970s he became a leading expert in cytogenetics and plant biosystematics.[3]
In the 1980’s Ray became an authority on chromosome pairing behavior in polyploids, proposing and testing models based on random synapsis and non-random distribution of chiasmata. He modified and applied these models to diploids, triploids, and tetraploids through octoploids. He also proposed similar models for predicting meiotic behavior in translocationheterozygotes.[3]
In 1947, in Brownstown, Indiana, he married Thelma June Snyder (b. 1929); they had a son and a daughter.[1]
Jackson, R. C. (1953). A Cytotaxonomic Study of Four Perennial Sunflowers: Helianthus mollis, H. doronicoides, H. tomentosus, and H. resinosus. Indiana University; 76 pp.{{cite book}}: CS1 maint: postscript (link)
Jackson, R. C. (1959). "A Study of Meiosis in Haplopappus gracilis (Compositae)". American Journal of Botany. 46 (7): 550–554. doi:10.1002/j.1537-2197.1959.tb07049.x.
Jackson, R. C. (1959). "Two New Species of Helianthus from New Mexico". Madroño. 15 (2): 54–57. JSTOR41422976.
Li, Ning; Jackson, R. C. (1961). "Cytology of Supernumerary Chromosomes in Haplopappus spinulosus ssp. cotula". American Journal of Botany. 48 (5): 419–426. doi:10.1002/j.1537-2197.1961.tb11660.x.
Jackson, R. C. (1962). "Interspecific Hybridization in Haplopappus and Its Bearing on Chromosome Evolution in the Blepharodon Section". American Journal of Botany. 49 (2): 119–132. doi:10.1002/j.1537-2197.1962.tb14917.x.
Jackson, R. C. (1963). "Variation in the Short Arm of Chromosome B of Haplopappus gracilis". Canadian Journal of Genetics and Cytology. 5 (4): 421–426. doi:10.1139/g63-059. ISSN0008-4093.
Jackson, R. C. (1965). "A Cytogenetic Study of a Three-Paired Race of Haplopappus gracilis". American Journal of Botany. 52 (9): 946–953. doi:10.1002/j.1537-2197.1965.tb07270.x.
Stucky, Jon; Jackson, R. C. (1975). "DNA Content of Seven Species of Astereae and Its Significance to Theories of Chromosome Evolution in the Tribe". American Journal of Botany. 62 (5): 509–518. doi:10.1002/j.1537-2197.1975.tb14077.x.
Jackson, R. C.; Jordan, R. G. (1975). "Haploidy in Haplopappus gracilis (N = 2)". American Journal of Botany. 62 (6): 628–632. doi:10.1002/j.1537-2197.1975.tb14093.x.
Arnold, M. L.; Jackson, R. C. (1978). "Biochemical, Cytogenetic and Morphological Relationships of a New Species of Machaeranthera sect. Arida (Compositae)". Systematic Botany. 3 (2): 208. doi:10.2307/2418314. JSTOR2418314.
Jackson, R. C. (1979). "Intersectional Hybridization in Haplopappus: Blepharodon x Hazardia". Systematic Botany. 4 (2): 157–162. doi:10.2307/2418853. JSTOR2418853.
Jackson, R. C.; Dimas, Calixto T. (1981). "Experimental Evidence for Systematic Placement of the Haplopappus phyllocephalus Complex (Compositae)". Systematic Botany. 6 (1): 8–14. doi:10.2307/2418630. JSTOR2418630.
Jackson, R. C.; Hauber, Donald P. (1982). "Autotriploid and Autotetraploid Cytogenetic Analyses: Correction Coefficients for Proposed Binomial Models". American Journal of Botany. 69 (4): 644–646. doi:10.1002/j.1537-2197.1982.tb13303.x.
Jackson, R. C.; Casey, Jane (1982). "Cytogenetic Analyses of Autopolyploids: Models and Methods for Triploids to Octoploids". American Journal of Botany. 69 (4): 487–501. doi:10.1002/j.1537-2197.1982.tb13284.x.
Jackson, R. C. (1982). "Polyploidy and Diploidy: New Perspectives on Chromosome Pairing and Its Evolutionary Implications". American Journal of Botany. 69 (9): 1512–1523. doi:10.1002/j.1537-2197.1982.tb13400.x.
Jackson, R. C. (1988). "A Quantitative Cytogenetic Analysis of an Intersectional Hybrid in Helianthus (Compositae)". American Journal of Botany. 75 (5): 609–614. doi:10.1002/j.1537-2197.1988.tb13484.x. PMID30139082.
Jackson, R. C.; Hauber, Donald P. (1994). "Quantitative cytogenetic analyses of autoploid and alloploid taxa in the Helianthus ciliarisgroup (Compositae)". American Journal of Botany. 81 (8): 1063–1069. doi:10.1002/j.1537-2197.1994.tb15595.x.
Jackson, R. C.; Jackson, Jeff W. (1996). "Gene segregation in autotetraploids: Prediction from meiotic configurations". American Journal of Botany. 83 (6): 673–678. doi:10.1002/j.1537-2197.1996.tb12756.x.
Jackson, R. C.; Skvarla, J. J.; Chissoe, W. F. (2000). "A unique pollen wall mutation in the family Compositae: Ultrastructure and genetics". American Journal of Botany. 87 (11): 1571–1577. doi:10.2307/2656732. JSTOR2656732. PMID11080106.
Jackson, R. C.; Ngo, N.; Ngo, H. (2002). "Chromosome-specific desynapsis in the n = 2 race of Haplopappus gracilis (Compositae)". American Journal of Botany. 89 (5): 777–782. doi:10.3732/ajb.89.5.777. PMID21665677.