Dr. Jude Grosser
Plant Cell Genetics
My research program in citrus variety improvement addresses all major citrus production problems in Florida, and also strives to develop new cultivars that will provide growers with new marketing opportunities. Using a team-oriented approach, my program is integrated with other members of the IFAS/CREC cultivar improvement team (F. G. Gmitter, W. S. Castle, and G. A. Moore) as well as entomologists, pathologists, and physiologists. I have been a consistently productive full professor, as evidenced by a ‘Superior’ faculty evaluation every full year that I have been employed by UF. Our citrus somatic hybridization program is the most successful in the world, resulting in somatic hybrid plants from more than 150 parental combinations. Most of these are now in field tests (in replicated commercial blocks) to determine their potential in scion and rootstock improvement. After collecting a few more years of yield and fruit quality data, we expect to release new somatic hybrid rootstocks to the industry that should have improved disease resistance (including blight, CTV, Phytophthora, and nematodes), better adaptation to poor soils, improved tree size control (which should facilitate mechanical harvesting and cold protection), improved nursery characteristics, and higher and more consistent productivity. Feedback from field trials is guiding current somatic hybridization research, and several mandarin + pummelo hybrids with potential to replace sour orange rootstock have been produced. Our successes in somatic hybridization have allowed us to initiate rootstock breeding and selection at the tetraploid level (a completely unique approach), resulting in the selection of more than 150 superior individual hybrids called “tetrazygs” to date (collaboration with J. H. Graham). Progress has also been made towards the development of rootstocks with improved tolerance of Diaprepes root weevil (collaboration with C.W. McCoy) or salinity (collaboration with J. P. Syvertsen). Somatic hybridization has been used to broaden the germplasm base available for rootstock improvement by producing hybrids with sexually incompatible or difficult to hybridize citrus relatives that possess valuable attributes. Numerous tetraploid somatic hybrids that combine elite diploid scion material have been produced and several flowering somatic hybrids are being used as pollen parents in our triploid breeding program (under the direction of F. G. Gmitter). Some of these somatic hybrids are producing quality fruit at the tetraploid level and a few may have cultivar potential on their own. We have built the largest collection of quality monoembryonic diploid females and quality tetraploid pollen parents in the world. More than 7000 triploid hybrids have been recovered from interploid crosses followed by embryo rescue, with a good percentage of these being fathered by somatic hybrids (in collaboration with F.G. Gmitter). This program will generate the seedless zipper-skin tangerines that the Florida citrus industry desperately needs to compete both nationally and internationally. Another approach to seedlessness is the transfer of CMS (cytoplasmic male sterility) from Satsuma to other elite but seedy Florida scions via cybridization, and so far we have achieved this with 4 cultivars (3 tangerines and one pummelo). This approach has the potential to make existing popular cultivars seedless, without otherwise altering cultivar integrity. Progress has also been made in the development of improved acid fruits (lemons and limes) and ornamental citrus. Triploid lime hybrids containing ‘Lakeland limequat’ germplasm that are resistant to citrus canker have been identified by screening using a stomatal inoculation method. Because sweet oranges and grapefruit are not amenable to conventional breeding, my program has focused on the generation of somaclonal variation to produce new cultivars. We have the largest field study in the world to evaluate somaclonal variation in woody fruit trees. Expected releases from this program in the near future include: Valencia sweet orange selections for processing with earlier or later maturity, or improved color and higher soluble solids (which will facilitate the shift from a concentrate market to an NFC-not from concentrate market in Florida); improved Valencia clones for fresh market with seedlessness, reduced rag, and altered maturity dates; and Hamlin sweet orange selections with earlier maturity, or improved color and higher soluble solids. One high-quality Valencia somaclone matures in January, two months ahead of standard Valencia. The molecular component of my research program has also made significant progress. We have developed an alternative citrus transformation method that utilizes GFP for selection and plant recovery via somatic embryogenesis - resulting in transgenic plants containing no bacterial resistance genes (more consumer friendly). In collaboration with the W. O. Dawson group (Plant Pathology), CTV-derived sequences are being screened for their ability to block CTV-replication, using an in-vitro protoplast assay. One transgenic sweet orange callus line containing the 392 CTV sequence has been identified that does not support CTV replication. Efforts to transfer this gene, other disease resistance genes (including potential canker resistance genes), and fruit quality genes (in collaboration with J. K. Burns) to commercial cultivars are underway, and transgenic plants are being produced. Recently, we regenerated transgenic Hamlin sweet orange plants that contain the Xa21 Xanthonomas resistance gene from rice in efforts to develop canker-resistant citrus (using the protoplast/GFP transformation system). Overall, my research program should impact many aspects of Florida citriculture in the near future.
- 1984 Ph.D. Univ. Kentucky, Lexington, KY, Agronomy/Plant Breeding & Genetics
- 1979 M.S. Morehead State University, Morehead, KY, Biology
- 1976 B.A. Thomas More College, Fort Mitchell, KY, Biology
Ananthakrishnan, G., V. Orbovic, S. Gowda, G. Pasquali, W.O. Dawson, and J.W. Grosser. 2006. Transfer of CTV-derived resistance candidate sequences to four grapefruit cultivars through Agrobacterium-mediated genetic transformation. Journal of the American Society for Horticultural Science (submitted).
Ananthakrishnan, G., M. Calovic, P. Serrano, and J.W. Grosser. 2006. Production of additional allotetraploid somatic hybrids combining mandarins and sweet orange with pre‑selected pummelos as potential candidates to replace sour orange rootstock. In Vitro Cellular & Developmental Biology Plant (accepted).
Grosser, J.W., G. Ananthakrishnan, W.W. Guo, M. Calovic, P. Serrano, J.L. Chandler, and F.G. Gmitter, Jr. 2006. Applications of somatic hybridization and cybridization in scion and rootstock improvement, with focus on Citrus. Acta Horticulturae (submitted).
Orbovic, V., G. Pasquali, and J.W. Grosser. 2006. A GFP-containing binary vector for Agrobacterium tumafaciens-mediated plant transformation. Acta Horticulturae (submitted).
Omar, A.A., and J.W. Grosser. 2006. Protoplast co-transformation and regeneration of transgenic ‘Hamlin’ sweet orange plants containing a cDNA of Xa21 Xanthonomas resistance gene and GFP. Acta Horticulturae (submitted).
Xu, X., J. Lu, J.W. Grosser, and P. Cousins. 2006. Isolation and culture of grape protoplasts from somatic embryogenic suspension cultures and leaves of Vitis vinifera and Vitis rotundifolia. Acta Horticulturae (submitted).
Guo, W.W., Y. Duan, O. Olivares-Fuster, Z. Wu, C.R. Arias, J.K. Burns, and J.W. Grosser. 2005. Protoplast transformation and regeneration of transgenic Valencia sweet orange plants containing a juice quality-related pectin methylesterase gene. Plant Cell Reports 24:482-486.
Guo, W.W., and J.W. Grosser. 2005. Somatic hybrid vigor in Citrus: direct evidence from protoplast fusion of an embryogenic callus line with a transgenic mesophyll parent expressing the GFP gene. Plant Science 168:1541-1545.
Viloria, Z., J.W. Grosser, and B. Bracho. 2005. Immature embryo culture and seedling development of acid citrus fruit derived from interploid hybridization. Plant, Cell, Tissue and Organ Culture 82:159-167.
Grosser, J.W., and F.G. Gmitter, Jr. 2005. 2004 SIVB Congress Symposium Proceedings “Thinking Outside the Cell” – Applications of somatic hybridization and cybridization in crop improvement, with citrus as a model. In Vitro Cellular & Developmental Biology Plant 41:220-225.
Viloria, Z., and J.W. Grosser. 2004. Acid citrus fruit improvement via interploid hybridization using allotetraploid somatic hybrid and autotetraploid breeding parents. Journal of the American Society for Horticultural Science 130:392-402.
Albiach-Marti, M.R., J.W. Grosser, S. Gowda, M. Mawasi, T. Satyanarayana, S. Garnsey, and W.O. Dawson. 2004. Citrus tristeza virus replicates and forms infectious virions in protoplasts of resistant citrus relatives. Molecular Breeding 14:117-128.
Guo, W.W., D. Prasad, Y.J. Cheng, P. Serrano, X.X. Deng, and J.W. Grosser. 2004. Targeted cybridization in citrus: transfer of satsuma cytoplasm to seedy cultivars for potential seedlessness. Plant Cell Reports 22:752-758.
Medina-Urrutia, V., K.F. Lopez-Madera, P. Serrano, G. Ananthakrishnan, and J.W. Grosser. 2004. New intergeneric somatic hybrids combining amblycarpa mandarin with six trifoliate/trifoliate hybrid selections for lime rootstock improvement. HortScience 39:355-360.
Grosser, J.W., V. Medina-Urrutia, G. Ananthakrishnan, and P. Serrano. 2004. Building a replacement sour orange rootstock: somatic hybridization of selected mandarin + pummelo combinations. Journal of the American Society for Horticultural Science 129:530-534.
Grosser, J.W., and J.L. Chandler. 2004. Production of twelve new allotetraploid somatic hybrid citrus breeding parents with emphasis on late maturity and cold-hardiness. Journal of the American Pomological Society 58:21-28.
Guo, W.W., D. Prasad, P. Serrano, F.G. Gmitter, Jr., and J.W. Grosser. 2004. Citrus somatic hybridization with potential for direct tetraploid scion cultivar development. Journal of Horticultural Science and Biotechnology 79:400-405.
Viloria, Z., D.L. Droulliard, J.H. Graham, and J.W. Grosser. 2004. A stomatal inoculation method for screening triploid hybrids of ‘Lakeland’ limequat for resistance to asiatic citrus canker (Xanthomonas axonopodis pv. Citri). Plant Disease 88:1056-1060.
Kahn, I.A., and J.W. Grosser. 2004. Regeneration and characterization of somatic hybrid plants of citrus sinensis (sweet orange) and citrus micrantha, progenitor species of lime. Euphytica 137:271-278.
Olivares-Fuster, O., G.H. Fleming, M.R. Albiach-Marti, S. Gowda, W.O. Dawson, and J.W. Grosser. 2003. CTV resistance in transgenic citrus based on virus challenge of protoplasts. In Vitro Cellular & Developmental Biology Plant 39:567-572.
Grosser, J.W., and J.L. Chandler. 2003. New citrus rootstocks via protoplast fusion. Acta Horticulturae 622:491-497.
Garcia-Sanchez, F., V. Martinez, J. Jifon, J.P. Syvertsen, and J.W. Grosser. 2002. Salinity reduces growth, gas exchange, chlorophyll and nutrient concentrations in diploid sour orange and related allotetraploid somatic hybrids. Journal of Horticultural Science and Biotechnology 77:379-386.
Moreira, C.D., F.G. Gmitter, Jr., J.W. Grosser, S. Huang, V.M. Ortega, and C.D. Chase. 2002. Inheritance of organelle DNA sequences in a Citrus-Poncirus intergeneric cross. Journal of Heredity 93:174-178.
Grosser, J.W. 2002. Introduction to the Colloquium “Genetic stability of transgenes under field conditions.” HortScience. p. 274.
Grosser, J.W. 2002. Somatic hybridization in citrus: A relevant technique for variety improvement in the 21st century. 10th IAPTC&B Congress: Plant Biotechnology 2002 and Beyond ACTA Horticulturae June 2002, p. 537-540.
Guo, W., and J.W. Grosser. 2002. Transfer of a potential canker resistance gene into citrus protoplasts using GFP as a selectable marker. ISHS/ASHS 2002 (Toronto, Canada) ACTA Horticulturae, August 2002.
Cabasson, C.M., F. Luro, P. Ollitrault, and J.W. Grosser. 2001. Non-random inheritance of mitochondria) genomes in Citrus hybrids produced by protoplast fusion. Plant Cell Reports 20:604-609.
Fleming, G.H., O. Olivares-Fuster, S. Fatta Del-Bosco, and J.W. Grosser. 2000. An alternative method for the genetic transformation of sweet orange. In Vitro Cellular & Developmental Biology Plant 36:450-455.
Grosser, J.W., and F.G. Gmitter, Jr. 2004. The continuing evolution of protoplast fusion as a tool for citrus variety improvement. Proceedings of the International Society of Citriculture 2004 (accepted).
Grosser, J.W., and F.G. Gmitter, Jr. 2004. The role of biotechnology in developing quality citrus fruits. Proceedings of the International Society of Citriculture 2004 (accepted).
Chandler, J.L., J.A. Browning, and J.W. Grosser. 2004. RAPD analysis of ‘Tetrazyg’ progeny from crosses of selected somatic hybrids for rootstock improvement. Proceedings of the International Society of Citriculture 2004 (accepted).
Ananthakrishnan, G., S. Gowda, V. Orbovic, W.O. Dawson, and J.W. Grosser. 2004. Regeneration of transgenic sweet orange and carrizo citrange plants containing a 742bp citrus tristeza virus‑derived sequence 392. Proceedings of the International Society of Citriculture 2004 (accepted).
Kahn, I.A., R.F. Lee, J.W. Grosser, and J. Hartung. 2004. Screening selected citrus germplasm for resistance to witches’ broom disease of lime (WBDL). Proceedings of the International Society of Citriculture 2004 (accepted).
Gmitter, F.G., Y. Wang, L. Wang, M.K. Wendell, P. Zhou, and J.W. Grosser. 2004. Triploid fresh fruit breeding at the UF-Citrus Research and Education Center. Proceedings of the International Society of Citriculture 2004 (accepted).
Guo, W.W., and J.W. Grosser. 2004. Transgenic sweet orange plant regeneration by protoplast co-transformation with a potential canker resistance gene and a GFP marker. Proceedings of the International Society of Citriculture 2004 (accepted).
Ananthakrishnan, G., and J.W. Grosser. 2004. Regeneration of transgenic sweet orange plants containing a 742bp Citrus Tristeza Virus-Derived Sequence 392. Proceedings of the International Society of Citriculture 2004 (accepted).
Rouseff, R., M. Morton, J. Smoot, and K. Mahattanatawee, and J.W. Grosser. 2004. Determination of aroma active leaf volatiles in new citrus hybrids using GC-MS and GC-olfactometry. Proceedings of the International Society of Citriculture 2004 (accepted).
Grosser, J.W. 2004. What’s new in citrus rootstock improvement: Introducing ‘Mandelos’ and ‘Tetrazygs’. Citrus Industry Magazine 85(2):22-24.
Grosser, J.W., J.H. Graham, C.W. McCoy, A. Hoyte, H.M. Rubio, D.B. Bright, and J.L. Chandler. 2003. Development of ‘Tetrazyg’ rootstocks tolerant of the Diaprepes/Phytophthora complex under greenhouse conditions. Proceedings of the Florida State Horticultural Society 116:262-267.
Grosser, J.W. 2003. Somatic hybridization – An important tool for citrus variety improvement in Florida. Proceedings of the International Lime Symposium (Colima, Mexico) (in press).
Arias, C., D. Lewandowski, O. Olivares-Fuster, J.W. Grosser, and J.K. Burns. 2003. Isolation, characterization, expression and down regulation of a putative thermostable pectinmethylesterase from Valencia orange. Proceedings of the International Society of Citriculture, p. 1265.
Calovic, M., Z. Viloria, B. Nielsen, F.G. Gmitter, W.S. Castle, and J.W. Grosser. 2003. Somatic embryogenesis from lemon styles and analyses of genetic stability in regenerated plants. ISC Congress 2000, p. 131-134.
Grosser, J.W., and J.L. Chandler. 2003. Development of improved Citrus rootstocks via somatic hybridization. Proceedings of the International Society of Citriculture, p. 47-50.
Grosser, J.W., J.L. Chandler, and F.G. Gmitter. 2003. Development of improved sweet oranges via somaclonal variation. Proceedings of the International Society of Citriculture, p. 42-45.
Grosser, J.W., F.G. Gmitter, and J.L. Chandler. 2003. The role of somatic hybridization in improving cold-hardiness and cold protection. Proceedings of the International Society of Citriculture, p. 410-412.
Grosser, J.W., X.X. Deng, and R.M. Goodrich. 2006. Somaclonal variation in sweet orange: practical applications for variety improvement and possible causes. In: Citrus Genetics, Breeding and Biotechnology. I.H. Kahn (Ed.). CAB International (accepted).
Ollitrault, P., W.W. Guo, and J.W. Grosser. 2006. Recent advances and evolving strategies in citrus somatic hybridization. In: Citrus Genetics, Breeding and Biotechnology. I.H. Kahn (Ed.). CAB International (accepted).
Orbovic, V., and J.W. Grosser. 2006. Citrus: Sweet orange (Citrus sinensis L. Osbeck ‘Valencia’) and Carrizo citrange [Citrus sinensis (L.) Osbeck x Poncirus trifoliata (L.) Raf.]. In: Agrobacterium protocols - methods in molecular biology. K. Wang (Ed.). Humana Press Inc., USA (in press).
Moore, G.A., F.G. Gmitter, Jr., and J.W. Grosser. 2005. Citrus, Grapefruit, Lemon, Lime, Orange, Etc. Chapt. 19, p. 583-626. In: Biotechnology of Fruit and Nut Crops. R.E. Litz (Ed.). CAB International, Wallingford, UK.
Guo, W.W., X.D. Cai, and J.W. Grosser. 2004. In: Molecular Biology and Biotechnology of Plant Organelles. Chapt. 24, 635-659. In. Somatic Cell Cybrids and Hybrids in Plant Improvement. H. Daniell and C.D. Chase (Eds.). Kluwer Academic Publisher, Dordrecht, The Netherlands.
Grosser, J.W., X.X. Deng, and R.M. Goodrich. 2004. Somaclonal Variation in Sweet Orange: Practical Applications for Variety Improvement and Possible Causes. In: Citrus Genetics, Breeding and Biotechnology. I. H. Kahn (Ed.). CAB International, Wallingford, UK (accepted).
Ollitrault, P., W.W. Guo, and J. W. Grosser. 2004. Recent Advances and Evolving Strategies in Citrus Somatic Hybridization. In: Citrus Genetics, Breeding and Biotechnology. I. H. Kahn (Ed.). CAB International, Wallingford, UK (accepted).