Research Horticulturist, USDA Agricultural Research Service
Curator, National Collection of Genetic   Resources for Pecans and Hickories
Webmaster, USDA ARS Pecan Breeding & Genetics
Adjunct Professor, Department of Horticultural Science, Texas A&M University and Department of Horticultural Science, Louisiana State Agricultural Center

USDA ARS Pecan Breeding & Genetics
10200 FM 50 S
Somerville, TX 77879
tel: 979-272-1402
cell: 979-255-1391
fax: 979-272-1401
email: lj.grauke@ars.usda.gov

L.J. Grauke received his Bachelor of Arts from the Plan II program, University of Texas-Austin in 1973. He received his Master of Science and Doctor of Philosophy in Horticulture, Texas A&M University in 1978 and 1982, respectively. Dr. Grauke was Associate Professor of Horticulture at Louisiana State University, working at the Pecan Research-Extension Station, Shreveport, La. prior to accepting the position as Research Horticulturist with USDA-ARS in 1988. He became a member of the graduate faculty at Texas A&M University in December, 1990 and also serves as an adjunct professor in the Department of Horticultural Sciences, Louisiana State Agricultural Center.

Dr. Grauke is Curator of the National Collection of Genetic Resources (NCGR) for Pecans and Hickories. The collection is the major germplasm repository for the genus Carya in the United States, and is dedicated to the collection, maintenance and characterization of world genetic resources of the Carya genus. Research includes practical aspects of species identification, designation, distribution, site adaptation, phenology, and relationships with associated insects and diseases. He has made collections of Carya in Mexico, Vietnam, and China as well as throughout the United States.  Molecular genetic markers developed in unit research are being used to characterize the geographic distribution of genetic diversity across the genus.

Dr. Grauke is Research Horticulturist for the USDA-ARS Pecan Breeding & Genetics program. The major objective of that program is the development of improved pecan cultivars and rootstocks for all U.S. production areas. Work is done cooperatively with Dr. Tommy E. Thompson, USDA ARS Geneticist. Controlled crosses are made using selected parents, and the resulting seedlings are carefully evaluated in nursery orchards. Individuals with outstanding performance are propagated in replicated test orchards where they are compared to standard pecan cultivars. These test orchards, known as the National Pecan Advanced Clone Testing System (NPACTS), form a national system of research orchards in which routine observations are made concerning growth, phenology, disease and insect resistance, nut production and nut quality. In addition to the routine evaluation of selections under test, research is also conducted for the improvement of selection criteria using standard field observations and molecular genetic techniques.

SELECTED PUBLICATIONS

Grauke, L. J., Mendoza-Herrera, M. A., Miller, A. J., and Wood, B.W. Geographic patterns of genetic variation in native pecans. Tree Genetics and Genomes (DOI 10.1007/s11295-011-0384-4) Published online: 25 March 2011

Sagaram, M., Lombardini, L. and Grauke, L. J. Variation in anatomical characteristics in leaves of pecan seedstocks from Mexico and the United States. J. Amer. Soc. Hort. Sci. J. Amer. Soc. Hort. Sci. 136: 103-108. 2011

Grauke, L. J., Mendoza-Herrera, M. A. and Binzel, M. L. Plastid microsatellite markers in Carya. International Society of Horticultural Sciences, Molecular Markers in Horticulture Symposium. Acta Horticulturae 859:237-246, 2010

Grauke, L. J. and Thompson, T. E. Pecan. In: Clark, J.R. and C.E. Finn. (eds.) Register of new fruit and nut cultivars- list 45. HortScience
45:716-756. 2010

Thompson, T.E. and Grauke, L.J. ‘Apalachee’ pecan: trial cultivar for all pecan growing areas. HortScience 45:1386-1387. 2010

Thompson, T.E. and Grauke, L.J. ‘Mandan’ pecan: trial cultivar for all pecan growing areas. HortScience 45:1392-1393. 2010

Volk, G.M., Waddell, J.W., Towill, L., Grauke, L.J. Variation in low temperature exotherms of pecan cultivar dormant twigs. HortScience. 44:317-321. 2009

Sagaram, M., Lombardini, L. and Grauke, L. J. Variation in leaf anatomy of pecan cultivars from three ecogeographic locations. J. Amer. Soc. Hort. Sci. 132: 1-5. 2007

Grauke, L. J., M. J. Iqbal, A. S. Reddy and T. E. Thompson. Development of microsatellite DNA markers in pecan. J. Amer. Soc. Hort. Sci. 128(3):374-380. 2003

Grauke, L. J. Hickories. Chapter 6. pp 117-166. In: Fulbright, Dennis (ed.) Nut Tree Culture in North America. Vol. 1. Northern Nut Growers Assoc., Inc. Pub. 2003

Grauke, L. J. Site selection and preparation. Chapter 10. pp 249-272. In: Fulbright, Dennis (ed.) Nut Tree Culture in North America. Vol. 1. Northern Nut Growers Assoc., Inc. Pub. 2003

Grauke, L. J., H. J. Price, and J. S. Johnston. Genome size of pecan determined by flow cytometry. HortScience 36:814. 2001

Lu, A. M., Stone, D. E. and Grauke, L. J. Juglandaceae. p 277-285. In Wu, Z. Y. and Raven, P. H. (eds) Flora of China, Volume 4, Cycadaceae throughFagaceae. Science Press (Beijing) and Missouri Botanical Garden Press (St. Louis). 1999