Mary W. Eubanks, Adjunct Professor of Biology

Contact Info:

Office Location:	016 Phytotron Building
Office Phone:	919-419-9315
Email Address:

Teaching (Fall 2009):

• EDUC 198S.03, TEACHING HS SCIENCE Synopsis

Education:

Ph.D.

University of North Carolina at Chapel Hill

1977

Specialties:

Genetics
Secondary Education
Genomics
Systematics
Evolution
Ecology and Population Biology

Research Interests: Maize Evolution and Improvement

Current projects: Drought tolerant maize, high protein maize, insect resistant/tolerant maize, aflatoxin tolerance in maize,, nitrogen use efficiency in tolerant maize

Maize Evolution - My research focus is the origin and evolution of maize (Zea mays L.). Today this important economic plant is grown in more countries of the world than any other crop. It has undergone such radical transformation under domestication that it can no longer survive without human intervention. The genesis and evolution of its complex genome has confounded maize geneticists and led to considerable controversy for decades. My research combines evidence from experimental breeding, archaeology, and comparative genomics to reconstruct the phylogenetic history of maize, trace its biogeographical dispersals, and understand its explosive evolution under human selection. Based on my seminal discovery that diploid perennial teosinte breaks the sterility barrier between Zea and Tripsacum, my hypothesis is that intergeneric hybridization was involved in maize domestication.

Zea-Tripsacum recombinant progeny recovered in experimental crosses closely resemble the earliest archaeological remains of maize. RFLP genotyping using 140 mapped molecular markers dispersed across the ten Zea linkage groups revealed evidence for intergeneric recombination between the two genomes. Over 20% of the maize genome is shared uniquely with Tripsacum, 36% is shared only with wild Zea, and over 43% is shared with Tripsacum and Zea. This finding supports the hybrid origin hypothesis, and is consistent with the origins of most important crop plants. Supporting evidence for a hybrid origin has recently been reported by Fu and Dooner, 2002, Proceedings of the National Academy of Sciences 99:9573 -9578; Orr, 2001, American Journal of Botany 88:363- 381, and Wilson et al. 1999, Genetics 153:453-473.

Maize Improvement - Since the Tripsacum-Zea recombinants are cross-fertile with maize, they provide a genetic bridge to move beneficial gamagrass genes into maize using conventional plant breeding methods. In a molecular marker assisted, recurrent selection breeding program, I have successfully transferred natural resistance to the worst insect pests of corn into breeding lines that are 99% maize. These corn rootworm and Eurpean corn borer resistant lines are also extremely drought tolerant. Yield tests in environmentally controlled growth chambers have shown there is no yield loss in hybrids experimentally subjected to 30% decrease in plant available water. Corn grown under the same conditions always incurs significant yield losses. During the summer of 2002, North Carolina had the worst drought in 150 years. I capitalized on this rare opportunity for a drought field test. The nursery was not irrigated all summer and the results were dramatic. None of the normal maize lines, which included drought tolerant Hopi blue corn, produced seed. All my hybrid lines had completely filled out ears!

Food Security - Development of maize that can perform well under targeted environmental stresses offers practical solutions for sustainable agriculture on marginally productive land areas. Drought tolerant, pest resistant corn that can be grown in low nitrogen, acid soils could be transferred into land races grown by poor subsistence farmers to alleviate hunger. A goal of the applied research is to test this model, which offers a pragmatic solution for insuring global food security as the challenges to world agricultural production accelerate with burgeoning human population growth and global climate change, in a humanitarian program for addressing hunger in developing countries.

Areas of Interest:

Plant breeding and genetics
Genomics
Ethnobotany
Economic Botany
Agroecology
Science Education

Keywords:

maize • corn • teosinte • Tripsacum • genomics • ethnobotany

Representative Publications   (More Publications)

1. M. Eubanks, Corn in Clay: Maize Paleoethnobotany in Pre-Columbian Art (1999), University of Florida Press, Gainesville
2. M.W. Eubanks, Genetic bridge to utilize Tripsacum germplasm in maize improvement, Maydica, vol. 51 no. 1 (February, 2006)  [abs]
3. M.W. Eubanks, Contributions of Tripsacum to maize diversity, in Darwin's Harvest, edited by T. J. Motley, N. Zerega and H. Cross (2005), pp. 91-117, Columbia University Press
4. M. Eubanks, The Myterious Origin of Maize, Economic Botany, vol. 55 no. 4 (2001), pp. 492-514
5. M. Eubanks and R. S. MacNeish, Comparative Analysis of the Río Balsas and Tehuacán Models for the Origin of Maize, Latin American Antiquity, vol. 11 no. 1 (2000), pp. 3-20