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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » People » Ann Callahan

Ann M Callahan

Research Geneticist

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Dr. Ann Callahan 
Research Geneticist
Phone: (304) 725-3451 ext. 356
Fax: (304) 728-7232
Room 210



Curriculum Vitae

Education and Degrees

1980 Ph.D.  Developmental GeneticsUniversity of Virginia, Regulation of Sexual Development in Volvox carteri, Robert Huskey, Advisor.

1974 A.B. Biology. Indiana University, Bloomington, IN


1989- Present

Research Geneticist, USDA-ARS, Appalachian Fruit Research Station, Kearneysville, WV 25430. Developing and utilizing molecular tools to improve breeding for fruit traits (Prunus and other temperate perennial fruit).


Research Associate, Plant Science Department, West Virginia University, Appalachian Fruit Research Station (Kearneysville). Molecular biology of fruit ripening (tomato).


Postdoctoral Fellow, University of Utah (Salt Lake). Bacterial Chemotaxis,-Threonine Serine Receptor (TSR) Sandy Parkinson, Advisor.


Laboratory Personnel

Dan Bullock

Callahan Laboratory Publications

Google Scholar:

Research Gate:

Current Projects

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Stone formation in Prunus

How are stones formed in Prunus and is it possible to manipulate gene expression to prevent the stone hardening?

We have planted several different plum trees (Prunus domestica, prune plums) that came from Luther Burbank’s breeding program from 1900, that have almost no stone. We are using these as breeding material to improve as well as experimental material to determine what the mutation is that prevents stone tissue from being formed. In addition we have identified genes involved in the process and have genetically engineered plum trees to test if by manipulating those genes there is an effect on the stone formation. These could then be targets for selective breeding

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Early Fruit Development

How do different parts of the flower become the fleshy edible part of the fruit?  We are working on a project primarily with Dr. Zhongchi Liu’s group at the U. Maryland, to understand the regulation of fleshy fruit development.  We are using 4 species that are closely related genomically but not by fruit types, Apple, Peach, Strawberry and Raspberry.  Peach and Raspberry are classic fruit where the ovary wall becomes fleshy.  In Apple the ovary wall is the core and the hypanthium becomes fleshy. In Strawberry, the ovary wall dries up and the receptacle becomes the fleshy part with the seeds naked on the surface.  We want to understand the molecular programs that specify which tissue becomes fleshy

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Accelerated breeding systems for Prunus

We have developed a way to speed up the plum breeding system utilizing a flowering gene (FT-1) from Populus.

 Plums transformed with an early flowering gene resulted in lines that have been continually flowering and fruiting in the greenhouse. The first flowers and fruit were seen after 9 months and now we can have fruit produced every year in the greenhouse.  This allows us to have a generation of plums every year instead of the 4-7 years in the field.