Using a combination of new tools and time-honored techniques, Dilip Panthee is carrying on North Carolina State University’s strong tradition in plant breeding, developing hardier, higher-yielding plants for North Carolina’s $30-million-a-year tomato industry.

North Carolina State’s College of Agriculture and Life Sciences has the nation’s largest university plant breeding program. Panthee, an assistant professor of horticultural science, proudly follows in the footsteps of Randy Gardner, a retired breeder credited with developing the cultivars used on some 60 to 75 percent of the vine-ripe tomatoes grown in the eastern United States.

When Panthee joined the faculty nearly five years ago, he brought skills in molecular marker-assisted breeding that he honed as a doctoral student and post-doctoral researcher at the University of Tennessee. And he came with a passion for and understanding of tomatoes that he gained during his early career as a breeder in Nepal, his home country.

Working at the Mountain Horticultural Crops Research and Extension Center in Mills River, Panthee focuses his efforts on developing tomato breeding lines and cultivars with three traits: disease resistance, fruit quality and stress tolerance. That’s because, in a survey the scientist conducted at the start of his tenure at North Carolina State, these three traits were the ones North Carolina growers reported needing the most.

To help address industry problems, Panthee takes a multi-faceted approach — part conventional breeding, part molecular marker-assisted selection (MAS). MAS isn’t genetic engineering; it’s simply a breeding short-cut that’s especially helpful when it comes to developing disease-resistant varieties using DNA-based markers.

In conventional breeding methods, scientists would inoculate plants with a disease to see which ones are resistant, but that runs the risk of spreading the disease, Panthee explains. However, with MAS, scientists can look for what are called markers — sequences of nucleotides that make up a segment of DNA — that are near the genes of interest in the genome.

To develop a tomato resistant to tomato mosaic virus, for example, Panthee has identified the molecular marker that is tightly linked with the TMV resistance gene, so as he breeds successive generations of plants, he selects only plants that contain that marker.