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Clemson University
college of agriculture, forestry and life sciences clemson university

Juan Carlos Melgar

Associate Professor of Pomology
Horticulture Program Team, Plant and Environmental Sciences Department, Public Service Activities

Office: BRC 218
Phone: 864-656-4562

Personal Website:


Educational Background

Ph.D. Crop Production and Protection
University of Cordoba, Spain 2006

B.S. Agricultural Engineering
University of Cordoba, Spain 2000

Courses Taught

Just Fruits, Horticulture 4550/6550

Creative Inquiry FLORECE: Future Leaders Obtaining Research and Extension Career Experiences


I have worked with fruit tree species under different climates for the last 20 years, including semiarid climates in the Mediterranean Basin (Spain and Italy) and subtropical humid climate in Florida, Texas and South Carolina. My research program is a combination of basic and applied research, in this case almost always driven by real problems that fruit tree growers have. I am also committed to inspire students and stimulate their interest and critical thinking.

Research Interests

My research in the last years focused on optimization of nutritional management, soil health, water-saving strategies, variety evaluations, and on the effect of biotic and abiotic stresses in physiological responses in peach, blackberry and citrus.

Extension and Outreach

My extension goals are to solve problems in fruit tree growing that can have significant economic, social and environmental impacts


Lawrence, B.T. and Melgar, J.C. 2024. Effect of municipal mulch and poultry litter amendments on soil and tree parameters of a mature peach orchard in a humid subtropical climate. Journal of Soil Science and Plant Nutrition. doi: 10.1007/s42729-024-01666-4

Caglar, U., Lawton, J.M., Melgar, J.C., and Gasic, K. 2024. Fruitlet freeze tolerance in peach germplasm. Agronomy 14(2): 302. doi: 10.3390/agronomy14020302

Kon, T.M., Fernandez, G., Melgar, J.C. and Lepsch, H. 2024. Identifying alternative management practices to promote blackberry lateral branch development. Acta Horticulturae 1388, 171-176. doi: 10.17660/ActaHortic.2024.1388.26

Lawrence, B.T., Calle, A., Saski, C.A., and Melgar, J.C. 2024. Differential gene expression patterns in peach roots under non-uniform soil conditions in response to organic matter. Genes 15(1): 70. doi: 10.3390/genes15010070.

Rodríguez-Bonilla, F., Tayal, M., Melgar, J.C. and Cieniewicz, E.J. 2023. Insights on the directional movement of Prunus necrotic ringspot virus between peach and wild Prunus species. Journal of Plant Pathology, 105: 1077-1085. doi: 10.1007/s42161-023-01450-w.

Lawrence, B.T., Dallman, L., Melgar, J.C. 2023. Organic matter amendments and their potential benefits to modern orchards in the southeastern United States. Journal of the American Pomological Society, 77(4): 213-225.

Lawrence, B.T. and Melgar, J.C. 2023. Annual compost amendments can replace synthetic fertilizer, improve soil moisture, and ensure tree performance during peach orchard establishment in a humid subtropical climate. Frontiers in Plant Science, 14:1172038. doi: 10.3389/fpls.2023.1172038

Nascimento-Silva, K., Coulombe, L. and Melgar, J.C. 2022. Influence of silicon on tolerance of water deficit of peach trees. HortScience. 58(4), 449-452. doi: 10.21273/HORTSCI16881-22

Abenina, M.I., Maja, J.M., Cutulle, M.A., Melgar, J.C. and Liu, H. 2022. Prediction of potassium in peach leaves using hyperspectral imaging and multivariate analysis. AgriEngineering, 4: 400-413. doi: 10.3390/agriengineering4020027

Lawton, J.M., Melgar, J.C. and Schnabel, G. 2022. Captan-induced bronzing and inking of peach skin and mitigation strategies. Acta Horticulturae, 1352: 49-54. doi: 10.17660/ActaHortic.2022.1352.6

Gasic, K., Adelberg, J., Baumgartner, K., Brannen, P.M., Cai, L., Calle, A., Chavez, D., Devkota, P., Gradziel, T.M., Hammerschmidt, R., Iezzoni, A., Koc, B., Mark, T., Melgar, J.C., Reighard, G.L., Saski, C., Schnabel, G., Tharayil, N. and Vassalos, M. 2022. Solutions to the Armillaria root rot affecting the US stone fruit industry. Acta Horticulturae, 1352: 501-508. doi: 10.17660/ActaHortic.2022.1352.68
Melgar, J.C., Lawrence, B.T. and Zhou, Q. 2022. Rational fertilization in peach orchards: considering orchard-specific variables to improve mineral nutrition programs. Acta Horticulturae, 1352: 169-176. doi: 10.17660/ActaHortic.2022.1352.23

Melgar, J.C., Zhou, Q., Lawrence, B.T., Gasic, K., Preece, J.E. and DeBuse, C. 2022 Tolerance of peach fruitlets to late spring freezes. Acta Horticulturae, 1346: 191-194. doi: 10.17660/ActaHortic.2022.1346.25

Nascimento-Silva, K., Benlloch-Gonzalez, M., Pavuluri, K. and Melgar, J.C. 2022. Effects of silicon on tolerance to water deficit in peach trees. Acta Horticulturae, 1333: 89-92. doi: 10.17660/ActaHortic.2022.1333.12

Lykins, S., Scammon, K., Lawrence, B.T. and Melgar, J.C. 2021. Photosynthetic light response of floricane leaves of erect blackberry cultivars from fruit development into the postharvest period. HortScience, 56: 347-351. doi: 10.21273/HORTSCI15571-20

Schnabel, G., Hu, M., Melgar, J.C. and Reighard, G.L. 2021. Mystery blotches on peach skin – what we know and don’t know about bronzing. Acta Horticulturae 1304: 283-288. doi: 10.17660/ActaHortic.2021.1304.39

Campbell D., Sarkhosh, A., Brecht, J., Gillett-Kaufman, J., Liburd, O., Melgar, J.C. and Treadwell, D. 2020. Bagging organic peaches reduces physical injuries and storage decay with minimal effects on fruit quality. HortScience 56(1): 52-58. doi: 10.21273/HORTSCI15391-20

Lawrence, B.T. and Melgar, J.C. 2020. Variable fall climate conditions on carbon assimilation and spring phenology on young peach trees. Plants 9 (10), doi: 10.3390/plants9101353

Zhou, Q. and Melgar, J.C. 2020. Tree age influences nutrient partitioning among annually removed aboveground organs of peach. HortScience 55: 560-564

Lawrence, B., Melgar, J.C., Dallmann, M., Ouellette, D., Mengjun, H. and Schnabel, G. 2020. Field performance and susceptibility to fungal pathogens of eleven blackberry cultivars. International Journal of Fruit Science, 20(sup2): 605-616. doi: 10.1080/15538362.2020.1749922

Zhou, Q. and Melgar, J.C. 2019. Ripening season affects tissue mineral concentration and nutrient partitioning in peach trees. Journal of Plant Nutrition and Soil Science 182: 203-209

Simpson, C.R., Melgar, J.C., Nelson, S.D. and Sétamou, M. 2019. Growth and yield responses under different grove management strategies for water conservation in young grapefruit trees. Scientia Horticulturae 256: 108567

Allran, J., Schnabel, G. and Melgar, J.C. 2019. Peach bagging in the Southeastern U.S. Journal of the American Pomological Society 73: 38-46

Kunta, M., Guzman, L., Garcia, A.C., del Rio, H.S., Melgar, J.C. and Louzada, E.S. 2019. Evaluation of physiological parameters in Citrus plants transformed with cyclic nucleotide gated ion channel (CNGC) gene. Acta Horticulturae 1230: 107-115

Lawrence B.T. and Melgar, J.C. 2018. Variable fall climate influences nutrient resorption and reserve storage in young peach trees. Frontiers in Plant Science 9: 1819. doi: 10.3389/fpls2018.01819

Lawrence, B. and Melgar, J.C. 2018. Harvest, handling, and storage recommendations for improving postharvest quality of blackberry cultivars. HortTechnology 28: 578-583

Penella, C., Calatayud, A. and Melgar J.C. 2017. Ascorbic acid alleviates water stress in young peach trees and improves their performance after rewatering. Frontiers in Plant Science, 8: 1627. doi: 10.3389/fpls.2017.01627

Hu, M-J., Peng, C., Melgar, J.C. and Schnabel, G. 2017. Investigation of potential causes of peach skin streaking. Plant Disease 101: 1601-1605

Nishikawa, F., Louzada, E., Melgar, J.C., Kunta, M. and Setamou, M. 2017. Effects of planting bed height and the use of plastic mesh as ground cover on the flowering of citrus trees. Bulletin of the NARO, Fruit Tree and Tea Science 1: 1-8

Kusakabe, A., Contreras-Barragan, B.A., Simpson, C.R., Enciso, J.M., Nelson, S.D. and Melgar, J.C. 2016. Application of partial rootzone drying to improve irrigation water use efficiency in grapefruit trees. Agricultural Water Management 178: 66-75

Contreras-Barragan, B.A., Kusakabe, A., Melgar, J.C. and Nelson, S.D. 2016. Understanding partial rootzone drying in citrus. Acta Horticulturae 1135: 123-130

Chaudhary, S., Kusakabe, A. and Melgar, J.C. 2016. Phytophthora infection in flooded citrus trees reduces root hydraulic conductance more than under non-flooded condition. Scientia Horticulturae 202: 107-110

Elsayed-Farag, S. and Melgar, J.C. 2015. Efficiency of tree-based water status indicators at the onset of water deficit in citrus. Horticulture, Environment, and Biotechnology 56: 305-309

Simpson, C.R., Nelson, S.D., Melgar, J.C., Jifon, J., Schuster, G. and Volder, A. 2015. Effects of salinity on physiological parameters of grafted and ungrafted citrus trees. Scientia Horticulturae 197: 483-489

Melgar, J.C. 2014. Issues in citrus fruit production. Stewart Postharvest Review 2: 1-4

Romero Conde, A., Kusakabe, A. and Melgar, J.C. 2014. Physiological responses of citrus to partial rootzone drying irrigation strategies. Scientia Horticulturae 169: 234-238

Melgoza, F.J., Kusakabe, A., Nelson, S.D. and Melgar, J.C. 2014. Exogenous applications of abscisic acid to increase freeze tolerance in citrus trees. International Journal of Fruit Science 14: 376-387

Simpson, C.R., Nelson, S.D., Melgar, J.C., Jifon, J., King, S.R., Schuster, G. and Volder, A. 2014. Growth response of grafted and ungrafted citrus trees to saline irrigation. Scientia Horticulturae 169: 199-205

Syvertsen, J.P., Albrigo, L.G. and Melgar, J.C. 2012. Mechanical harvesting and citrus tree stress in Florida. Acta Horticulturae 928: 281-286

Melgar, J.C., Mohamed, Y., Serrano-Castillo, N., Garci­a-Galavi­s, P.A., Navarro, C., Parra, M.A., Beltran, G., Benlloch, M. and Fernandez-Escobar, R. 2012. Response of olive trees to irrigation with saline water. Acta Horticulturae 949: 279-282

Melgar, J.C., Dunlop, J. and Syvertsen, J.P. 2011. Oleocellosis injury of fruitlets from late season mechanical harvesting of 'Valencia' orange trees does not affect internal fruit quality. HortScience 46: 457-459

Alvarez-Fernandez, A., Melgar, J.C., Abadi­a, J. and Abadi­a, A. 2011. Fruit quality and yield changes in pear (Pyrus communis L.) and peach (Prunus persica (L.) Batsch) trees as affected by iron deficiency chlorosis. Environmental and Experimental Botany 71: 280-286

El Jendoubi, H., Melgar, J.C., Alvarez-Fernandez, A., Sanz, M., Abadi­a, A. and Abadi­a, J. 2011. Setting good practices to assess the efficiency of iron fertilizers. Plant Physiology and Biochemistry 49: 483-488

Melgar, J.C., Dunlop, J., Albrigo, L.G. and Syvertsen, J.P. 2010. Winter drought stress can delay flowering and avoid immature fruit loss during late-season mechanical harvesting of ‘Valencia’ oranges. HortScience 45: 271-276

Syvertsen, J.P. Melgar, J.C. and Garci­a-Sanchez, F. 2010. Salinity tolerance and leaf water use efficiency in Citrus. Journal of the American Society for Horticultural Science 135: 33-39

Melgar, J.C., Dunlop, J. and Syvertsen, J.P. 2010. Growth and physiological responses of Swingle citrumelo Citrus rootstock seedlings to partial rootzone drying and deficit irrigation. Journal of Agricultural Science 148: 593-602

Melgar, J.C., Schumann, A.W. and Syvertsen, J.P. 2010. Fertigation frequency affects growth and water and nitrogen use efficiencies of Swingle citrumelo citrus rootstock seedlings. HortScience 45: 1255-1259

Remorini, D., Melgar, J.C., Guidi, L., Degl'Innocenti, E., Castelli, S., Traversi, M.L., Massai, R. and Tattini, M. 2009. Interaction effects of root-zone salinity and solar irradiance on the physiology and biochemistry of Olea europaea. Environmental and Experimental Botany 65: 210-219

Melgar, J.C., Mohamed, Y., Serrano, N., Garci­a-Galavi­s, P.A., Navarro, C., Parra, M.A., Benlloch, M. and Fernandez-Escobar, R. 2009. Long term responses of olive trees to salinity. Agricultural Water Management 96: 1105-1113

Melgar, J.C., Guidi, L., Remorini, D., Agati, G., Degl'Innocenti, E., Castelli, S., Baratto, M.C., Faraloni, C. and Tattini, M. 2009. Antioxidant defences and oxidative damage in salt-treated olive plants under contrasting sunlight irradiance. Tree Physiology 29: 1187-1198

Melgar, J.C., Syvertsen, J.P. and Garcia-Sanchez, F. 2008. Can elevated CO2 improve salt tolerance in olive tree cuttings? Journal of Plant Physiology. 165: 631-640

Melgar, J.C., Syvertsen, J.P., Marti­nez, V. and Garci­a-Sanchez, F. 2008. Leaf gas exchange, water relations, nutrient content and growth in citrus and olive seedlings under salinity. Biologia Plantarum. 52: 385-390

Melgar, J.C., Mohamed, Y., Navarro, C., Parra, M.A., Benlloch, M. and Fernandez-Escobar, R. 2008. Long term growth and yield responses of olive trees to different irrigation regimes. Agricultural Water Management 95: 968-972

Tattini, M., Melgar, J.C. and Traversi, M.L. 2008. Responses of Olea europaea to high salinity: a brief ecophysiological review. Advances in Horticultural Science 22: 1-15


Melgar's lab website
Melgar's lab video
Melgar's lab video (en español)
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