• Development of new sweet potato cultivars; sweet potato molecular genetics; disease and insect resistance

As a sweet potato breeder and geneticist, my program is focused on developing new varieties for the sweet potato industry. This is a collaborative effort with a number of scientists at the LSU AgCenter. Industry needs change, but several constants remain - high yield and disease resistance. The industry today is faced with two major issues: growing production costs and crop loss due to flooding. At the same time, the industry is enjoying increased consumer demand through new value added products.

Counteracting higher production costs comes in a number of ways. Increased yield with no increased economic input is a classic and difficult to achieve given the high yield of today’s varieties – but we keep trying! Other more subtle options include improved shape and higher grade out. Markets are increasingly demanding and so many storage roots are not shipped because of minor shape imperfections. Increasing the percent of storage roots which make it in the shipping box is very important. The breeding program is also venturing into developing varieties with a tougher skin to enable mechanical harvest with fewer people involved. These varieties will be for processing and may not be acceptable on the fresh market, but given the growth in the processing sector, it is a clear priority.

The genetics program is closely allied with the breeding program. Our current emphasis is to identify and characterize genes which are involved in storage root development and environmental factors critical in storage root initiation. There is also a keen interest in understanding skinning resistance. The sweet potato research group at the LSU AgCenter, along with out-of-state collaborators, was awarded a Specialty Crop Research Initiative grant through the USDA in 2009. Many of the objectives in this grant relate to improving production efficiency and developing a production model to aid growers in making informed decisions. Breeding/genetics efforts related to this grant will target skinning, bulk harvest and storage, and rhizopus soft rot resistance.

Administration:
I currently serve as the interim director of the School of Plant, Environmental and Soil Sciences.

Research Contribution:
Plant breeding is by nature a cooperative endeavor. The sweet potato scientific and extension group at the LSU AgCenter is closely involved in the evaluation and development of new varieties. Our most recent release is Evangeline – a deep orange flesh variety with unusually high sucrose content. The premium flavor makes it a favorite as a table stock variety and one ideally suited for processing. The yield is competitive with the industry standard, Beauregard, and it does hold up well in flooded soil. Our breeding program also recently released the popular Murasaki-29 - a purple skin, white flesh variety. Specialty types represent a small but growing segment of the industry.

Teaching Experience:
I team teach two classes - HORT 2860 – Growth and Development of Agricultural Crops, and HORT 7071 – Advanced Plant Genetics. I also coordinate the horticulture internship class, HORT 3000. Until recently I served as the undergraduate advisor to horticulture students and the curriculum coordinator for the horticulture offerings in Plant and Soil Systems.

Publications:
Villordon, A., D. La Bonte, N. Firon, Y.Kfir, E. Pressman, and A. Schwartz.
2009. Characterization of adventitious root development in sweetpotato. HortScience (in press).

Villordon, A., D. LaBonte, and N. Firon. 2009. Development of a simple thermal time method for describing the onset of morpho-anatomical features related to sweetpotato storage root formation. Scientia Horticulturae 121:374-377.

McGregor, C., D. Miano, D. LaBonte, M. Hoy, and C. Clark. 2008. The effect of the causal agent of Sweet Potato Virus Disease on symtom severity and individual virus titres in sweet potato cv. Beauregard. J. Phytopathology (in press)

Villordon, A., C. Clark, D. Ferrin, and D. LaBonte. 2009. Using growing degree days, agrometeorological variables, linear regression, and data mining methods to help improve prediction of sweetpotato harvest data in Louisiana. HortTechnology (in press).

Courtney, M., M. Mcharo, W. Gruneberg, and D. La Bonte. 2008. Heritability estimates for micronutrient composition of sweetpotato storage roots. HortScience 43:1382-1384.

Miano, D.W., D.R. La Bonte, and C.A. Clark. 2008. Identification of molecular markers associated with sweet potato resistance to sweet potato virus disease in Kenya. Euphytica 160:15-24.

La Bonte, D.R., C.A. Clark, A.Q. Villordon, and P.W. Wilson. 2008. Evangeline sweetpotato. HortScience 43:258-259.

La Bonte, D.R., C.A. Clark, A.Q. Villordon, P.W. Wilson, and C.S. Stoddard. 2008. Murasaki-29 sweetpotato. HortScience 43:1895-1896.

Lockwood, S., J.M. King, and D.R. LaBonte. 2008. Altering pasting characteristics of sweet potato starches through amino acid additives. J. Food Sci. 73:373-377.

Villordon, A., W. Njuguna, S. Gichuki, P. Ndolo, H. Kulembeka, S. Jeremiah, D. La Bonte, B. Yaka, P. Tukamuhabwa, and R. Mwanga. 2006. Using GIS-based tools and distribution modeling to determine sweetpotato germplasm exploration and documentation priorities in sub-Saharan Africa. HortScience 41:1377-1381.

Menelaou, E., A. Kachatryan, J. Losso, M. Cavalier, and D. La Bonte. 2006. Lutein content in sweetpotato leaves. HortSci. 41:1-3.

Miano, D.W., D.R. La Bonte, C.A. Clark, R.A. Valverde, M.W. Hoy, S.Hurtt, and R. Li. 2006. First report of a Begomovirus infecting sweetpotato in Kenya. Plant Disease 90:832.

McGregor, C.E. and D.R. La Bonte. 2006. Differential expression of genes between storage roots of sweetpotato cultivars Jewel and White Jewel. J. Amer. Soc. Hort. Sci. 798-805.

Kokkinos, C., C. McGregor, C. Clark, and D. La Bonte. 2006. The Effect of Sweet Potato Virus Disease and Its Viral Components on Gene Expression Levels in Ipomoea batatas (L.) Lam. J. Amer. Soc. Hort. Sci. 131:657-666.

McGregor, C.M., B. Sosinski, J. Jankowicz, K. Burg, L. He, R. Brier, and D. La Bonte. 2005. The effect of replicate number and image analysis method on sweetpotato [Ipomoea batatas (L.) Lam.] cDNA microarray results. Plant Mol. Biol. Rept. 23:367-381.

Mcharo, M., D. La Bonte, C. Clark, M. Hoy, and J. Oard. 2005. Molecular Marker Variability for Southern Root-Knot Nematode Resistance in Sweetpotato. Euphytica 144:125-132.

Mcharo, M., D. La Bonte, R. Mwanga, and A. Kriegner. 2005. Associating molecular markers with virus resistance to classify sweetpotato genotypes. J. Am. Soc. Hort. Sci. 130: 355-359.

La Bonte, D. C. Clark, A. Villordon, J. Cannon, M. Hoy, M. Sistrunk, E. Freeman, and G. Roberts. 2004. Yield of four generations of virus-tested sweetpotato. HortTech. 14:320-322.

Villordon, A., J. Franklin, and D. La Bonte. 2004. Using personal digital assistants and database forms as tools for field data collection. HortTech. 14:402-405.

Book Chapters:
N. Firon, Y. Kfir, and E. Pressman, D. LaBonte, A. Villordon and C. McGregor. 2009. Storage root formation and development. In: (G. Loebenstein and G. Thottappilly) The Sweet Potato. Springer Verlag Press (in press).

Patents:
LaBonte, D.R., C.A. Clark, and A.Q. Villordon. 2009. Murasaki-29 Sweetpotato. US PP 19955.

LaBonte, D.R., C.A. Clark, and A.Q. Villordon. 2009. Evangeline Sweetpotato. US PP 19710.

LaBonte, D.R., C.A. Clark, J.M. Cannon, P.W. Wilson, and A.Q. Villordon. 2004. Sweetpotato plant named ‘L96-117’. US PP15,038 P2.

LaBonte, D.R., C.A. Clark, J.M. Cannon, P.W. Wilson, A.Q. Villordon, A.H. Hammond, and R.N. Story. 2004. Bienville sweetpotato. US PP15,380 P3.