Meet the Peach Team at Clemson University

IMG_5110From left to right: Jeff Hopkins, Dr. Ksenija Gasic, Dr. Douglas Bielenberg, Dr. Juan Carlos Melgar, and Dr. Guido Schnabel.

At Clemson University in South Carolina, a group of faculty researchers, county extension agents and specialists are working together to solve the problems of the peach industry. The Peach Team is an interdisciplinary team of researchers and extension agents that provide research-based information to advance the fruit industry in South Carolina and beyond. Although research is also carried out in orchards in several parts of the state, most of Clemson University’s fruit tree research takes place at the Musser Fruit Research Center. The Musser Farm’s manager, Jeff Hopkins, and technical staff (Kathy Brock, Dave Ouellette, Sam Hudson, and Brandon Padget) help the Peach Team to accomplish its research objectives. The 240-acre research farm is a model fruit research facility for the Southeast and has an extensive collection of peach and nectarine cultivars, as well as related Prunus species and interspecific hybrids.

Dr. Greg Reighard has been a research and extension horticulturalist for 30 years at Clemson University. His field research involves rootstock evaluation, growth regulators, manipulating peach tree dormancy/flowering, crop load management strategies, modeling fruit maturity, and adapting mechanical technologies for training systems. His lab has conducted genomics research on dormancy (Evg mutant) and rootstock resistance to nematodes and peach tree short life, and he co-developed Guardian® rootstock as well as its eventual PVP and trademark. Dr. Reighard is the Peach Section Chair for the International Society of Horticultural Science, and is a Fellow of the American Society of Horticultural Science.

Dr. Guido Schnabel is a plant pathologist with research and extension responsibilities. He focuses on fungal diseases affecting the peach tree and fruit. His research over the last 15 years led to a better understanding of why important fungicides are losing their efficacy to control key diseases such as brown rot, Alternaria rot, and peach anthracnose. He developed a horticultural technique (above ground root collar excavation) to reduce Armillaria root rot (oak root rot), which is used now to more successfully grow peaches on replant sites. His extension activities include the testing of fungicides for disease control, development and promotion of management strategies to improve the efficacy and the life span of reduced-risk fungicides, and the determination of farm-specific resistance profiles to help growers fine-tune their spray program. His most recent extension efforts were geared toward the development of a smartphone application, MyIPM, which provides growers with disease and resistance management information. The app is available in Google Play for Android phones and will soon be available in the Apple Store for iPhones.

Clemson University revived peach breeding program after 25 years by hiring Dr. Ksenija Gasic, peach breeder and geneticist, in 2008. Her research is focused on development of high quality, disease resistant peach varieties adapted to environmental conditions of the Southeastern U.S. She is developing early- to late-ripening, fresh market types of peaches and nectarines that meet the demands of consumers and provide the highest return on investment for growers. The emphasis is on combining high quality and consistent productivity with improved resistance to bacterial spot and brown rot and health benefits in new peach varieties. Dr. Gasic’s research involves characterization and utilization of the peach genetic diversity and development and utilization of genomic technology to improve breeding efficiency. Her program has been actively involved in development and application of modern technological tools in breeding programs (www.rosbreed.org).

Dr. Simon Scott is a plant virologist working primarily with viruses and other graft-transmissible agents in woody species in general and peach in particular.  Research areas involve virus characterization with the aim of developing sensitive detection techniques and identification and analysis of the agents in “Ta Tao 5” germplasm associated with bloom delay. A major area of involvement is with the National Clean Plant Network, to make available the highest quality propagating material for the nurseries, and trees to the peach producers in the Southeastern U.S. Each spring, blocks of trees of commercially significant cultivars maintained on grower properties are indexed for the presence of Prunus necrotic ringspot, Prune dwarf, and Plum pox viruses. Results are supplied to the major nurseries in Tennessee to insure the budwood they collect from these blocks for “June budding” is not infected with these viruses.  The trees that produce seed of Guardian rootstock are indexed for the same viruses.

Dr. Douglas Bielenberg studies the interaction between plants and the abiotic environment. A major emphasis of his program has been investigating the molecular and genetic basis of dormancy behavior in peach. Bud chilling and heat requirement are major determinants of bloom time. Matching the chilling requirement of trees to our local climate is an important selection criteria used by breeders, and his program seeks to develop molecular markers for chilling requirement and bloom time traits that can be used in marker-assisted selection by the SC peach breeding program. He is also starting two projects to identify genetic markers for maximum fruit size potential in the breeding stock used by the SC breeding program, and to identify molecular markers for the dormancy status of floral buds that will assist in grower decision making for cultural practices that manipulate bud break timing.

Dr. Juan Carlos Melgar, pomologist, is the latest addition to the Peach Team at Clemson. He joined Clemson University in August 2014. Since then, he has started developing research on optimization of irrigation using soil and tree-based sensors, and fertilization, using a holistic approach that includes the assessment of nutrient remobilization and soil nutrient losses. Dr. Melgar will take over the annual evaluations of advanced selections and new varieties for their performance in SC in commercial orchards as well as at the Musser Farm, and plans to develop some postharvest studies in the near future.

Several extension agents work together with these scientists to address South Carolina’s peach industry problems. Area Horticultural Agent Greg Henderson serves the growers of peaches and small fruit in the Midlands and Coastal Region of SC. His primary focus is serving the commercial peach industry in the largest production area of SC comprising approximately 14,000 acres of fruit. His duties include, but are not limited to, developing issue specific programming to address production concerns as well as working closely with specialists and the industry in research activities to improve production, fruit quality, and orchard sustainability. Current research is focused on soil health in Southeastern peach production systems. Andy Rollins is the Horticultural Agent for the upstate of SC. He is specialized in commercial fruit and vegetable production and assists new growers with problem diagnosis and multiple decisions including soil testing/preparation, location/size of the planting, spray choices, calibration, and variety selection.  Andy is actively involved in research projects with Clemson University as well as USDA-ARS specialists, and also does some new product testing. Anthony (Tony) Melton is the Horticulture Agent for the Pee Dee region of SC. He works with the production of all commercial and home turf, ornamentals, nuts, and fruits, and assists one large shipper, two small local growers/marketers, and many homeowners with the production of peaches.

Professors and tree fruit specialists from other universities but with a joint appointment at Clemson University are also part of the Peach Team. Dr. Dan Horton, professor of entomology at the University of Georgia, has been providing extension entomology programming for peach trees for over 20 years. His IPM programs have helped growers meet escalating societal standards for food safety, worker safety, and environmental stewardship. He has also participated in numerous collaborative peach research efforts, including research on the peachtree/lesser peachtree borer complex, and scale. Finally, Wayne Mitchem is an Extension Associate at NC State University with weed management responsibilities in tree fruit crops.  His position is funded cooperatively by NCSU, Clemson University, and the University of Georgia to conduct applied research, grower meetings, develop recommendations, and provide assistance to county agents, as well as fruit growers in NC, SC, and GA.