The problem with North Carolina . . . and turfgrass

Media Contact: Dr. Susana Milla-Lewis, assistant professor of crop science, North Carolina State University, 919.515.3196 or susana_milla-lewis@ncsu.edu

North Carolina is not the best place in the world to establish a luxuriant lawn, or to cover a football field or golf course with turf, and therein lies Dr. Susana Milla-Lewis’ challenge.

Milla-Lewis is a plant breeder in the College of Agriculture and Life Sciences at North Carolina State University. She was hired in 2009 to establish a turfgrass breeding program.

The problem with North Carolina when it comes to turfgrass, Milla-Lewis explains, is that the state is in a climatic transition zone. North Carolina has hot summers, yet the winters can get fairly cold. The various species of turfgrass tend to like it one way or the other, hot or cold. Indeed, turfgrasses are lumped into two categories: warm-season and cool-season.

Warm-season grasses like St. Augustinegrass, bermudagrass, centipedegrass, zoysiagrass and bahiagrass like it hot. These turfgrasses go dormant and turn brown during the winter, then green up in the summer. Cool-season grasses like fescue, the predominant turf in North Carolina, and perennial ryegrass, prefer cooler temperatures.

The problem in North Carolina, Milla-Lewis says, is that warm-season grasses tend to experience winter kill from cold temperatures, while cool-season grasses have difficulty with the heat and drought of a typical North Carolina summer. As a turfgrass breeder, Milla-Lewis is out to change this state of affairs.

Milla-Lewis is working with the five warm-season and two cool-season turfgrasses mentioned previously, looking for a range of useful traits, but chief among these are cold tolerance among the warm-season grasses and heat- and drought-tolerance among the cool-season turfgrasses.

While it would be inaccurate to say Milla-Lewis began this quest with nothing, she did not start with much. While N.C. State has a long and illustrious plant-breeding history, that history does not extend to turfgrass breeding.

As Milla-Lewis puts it, “I had a big greenhouse, but it was an empty greenhouse. There was almost no breeding material to work with.”

A well-established plant breeding program might have 1,000 breeding lines, or plants with different, known characteristics. Milla-Lewis had 10 different kinds of bermudagrass and 30 different kinds of St. Augustinegrass. The bermudagrass came from South Africa, where Dr. Rick Brandenburg, an N.C. State entomologist who works with insects that damage turf, collected it because it appeared to be shade-tolerant.

Milla-Lewis spent much of her first year traveling around the country, visiting other turfgrass breeders and collecting turfgrass samples.

“The first few months in this job, I did some travelling and visited the main turfgrass breeding programs in the South, plus a few private companies in Oregon looking for materials. Several collaborations were established, and we managed to negotiate transfer of materials from both public and private sources for several different species,” Milla-Lewis says. She now has more than 900 different types of turfgrass.

A plant breeder also needs a place to grow plants, and Milla-Lewis has two, the Lake Wheeler Road Turfgrass Field Laboratory just outside the Raleigh city limits and the Sandhills Research Station near Jackson Springs, N.C. Both sites are equipped with shade structures that allow Milla-Lewis to grow turfgrass in constant shade, while in the Sandhills, she is also growing turfgrass in a large hoop structure that can be covered with plastic. This structure allows her to create artificial drought and evaluate the plants growing inside for drought-tolerance.

Milla-Lewis started planting the turfgrasses she had collected in 2010. “In the summer of 2010 we managed to establish 14 trials, which is quite a bit for someone who is just starting,” she says. “Everything we planted, we planted on our hands and knees, over 15,000 plugs.”

In 2011, Milla-Lewis will evaluate those 2010 plantings. She’ll be looking for strength where different types of turfgrass typically are weak. Among the different types of tall fescue she has planted, for example, she’ll be looking for that unusual tall fescue plant that can tolerate heat, drought and shade. The ability to resist a disease called brown patch would also be nice. Bermudagrass has been planted under one of her shade structures, where it can be evaluated for shade and cold tolerance. In zoysiagrass, she’s looking for cold tolerance and the ability to resist large patch disease. And zoysiagrass tends to take time to cover an area, or become established, so she’d like to see some zoysiagrass that spreads more quickly. In St. Augustinegrass, she’s looking for cold tolerance, attractive leaves, and chinch bug and gray leaf spot resistance.

Then there’s centipedegrass, which tends toward a sameness that is the bane of plant breeders. A plant breeder wants to see differences in the plants he or she grows. Differences in color, size, shape and the way plants react to their environment indicate genetic variability, and once a breeder identifies that variability, he or she can begin to tease it out and eventually develop a new variety. Milla-Lewis has used chemicals to cause mutations in centipedegrass, and she’s hoping some of those mutants will be more cold-tolerant, establish themselves more quickly or show more variability in color and leaf texture.

Milla-Lewis is also using molecular technologies to look for genetic markers that indicate different traits and working to map the genomes of turfgrasses to better understand their genetics.

Growing and tending turfgrass in North Carolina, whether for home lawns, football fields, golf courses or just roadsides is a nearly $5 billion industry, Milla-Lewis says, so if she is successful in developing new types of turfgrass that are suited to North Carolina conditions, there could be significant economic repercussions.

She points out, for example, that much of her work is focused on finding drought-tolerant turfgrasses at a time when water is increasingly seen as a limited resource. Drought tolerance would allow those who tend turfgrass, from homeowners to golf course superintendents, to save on water bills and the government entities that provide water to conserve.

If Milla-Lewis is successful, she will provide North Carolinians with what might be called a Goldilocks turfgrass, a type of turfgrass that is just right for North Carolina.

Written by: Dave Caldwell, 919.513.3127 or dave_caldwell@ncsu.edu

North Carolina State University and the College of Agriculture and Life Sciences have a long and productive history of plant breeding. To learn more, please visit our AgAdvantage Crop Breeding page or the Center for Plant Breeding and Applied Plant Genomics