Susana Milla-Lewis

While zoysiagrass has great potential for use on low maintenance areas, its use for golf course roughs is sparse. Breeding programs have ����������������coarse-textured��������������� germplasm available that has excellent stress and pest tolerance and fast establishment when managed with no inputs, but these materials are often discarded because current breeding efforts are more focused on ����������������fairway��������������� and ����������������putting green��������������� zoysiagrass. Our research team has evaluated zoysiagrasses for their performance and playability in multiple climates (warm-arid, warm-humid, transition zone) as a potential grass for golf course roughs and other low-maintenance areas. Entries with superior drought tolerance, aggressiveness and color retention in combination with acceptable ball lie were as part of those efforts. The objectives of the current study are to 1) expand evaluation of these materials to larger areas to fully assess their performance under golf conditions, 2) initiate evaluation of newly developed low input materials, and 3) develop materials with improved large patch tolerance.

The turfgrass industry is a multibillion dollar industry in the United States, and represents tens of thousands of jobs related to production, installation, and management of turfgrasses. Outside of its significant economic impacts, turfgrasses also provide significant environmental and social benefits. Despite these numerous benefits, the turfgrass industry faces many serious challenges. Greatest among these is the limited availability and reduced quality of water for irrigating turfgrass areas. Although sustainable landscapes are a concern throughout the country, severe droughts and limited water in California and the Southwestern United States are already forcing changes to the landscape. Due to increasingly limited water resources and the desire to have more sustainable landscapes, there is a growing need for turfgrasses which can withstand drought conditions. A transdisciplinary group from North Carolina State University (NCSU), Oklahoma State University (OSU), Texas A&M AgriLife Research (TAMUS), the University of Georgia (UGA), and the University of Florida (UF) was formed to address these problems and to develop turfgrasses with reduced irrigation requirements for use in southern landscapes. These efforts have focused on economically important warm-season turfgrass species, bermudagrass [Cynodon spp. (L.) Rich], zoysiagrass (Zoysia spp. Steud.), St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and seashore paspalum (Paspalum vaginatum Swartz), that have the potential to significantly reduce water use in future landscapes. To date eight improved cultivars have been released from this project. However, additional efforts are needed to continue the development pipeline for new cultivars and genetic tools, promote their adoption, and quantify their impact. Advancing this successful research relationship will allow for efficient progress towards improved screening methods and molecular markers using new tools and technologies, the dissemination of important information to stakeholders and end-users, and ultimately allow for the continued utilization of turfgrasses in sustainable landscapes.

Genetics and applied plant breeding can be used to improve aesthetics, performance, and overall abiotic and biotic stress tolerance of warm-season turfgrasses, which would ultimately affect the efficiency and ease of their maintenance and production. Development of warm-season turfgrass cultivars that are better adapted to environmental conditions in North Carolina would significantly contribute to different sectors of the turfgrass industry in our region. Zoysiagrass and St. Augustinegrass are warm-season, perennial turfgrass species well-adapted for home lawns and commercial landscapes across the southern US and upwards into the transition zone. Given that these grasses require lower maintenance inputs than other warm-season grasses, expanding their use could have a significant impact in making landscapes more environmentally friendly. However, both species could use improvement in their tolerance to abiotic and biotic stresses. In an attempt to address these issues, we have initiated programs to develop populations with improved stress tolerance and turf quality in both species. Promising hybrids have been identified through multi-location evaluations during the past five years. These lines will need to be advanced to on-farm trials where they will be evaluated for production traits (establishment speed, regrowth, harvestability, sod strength) in order to assess their potential for commercial release.

St. Augustinegrass (Stenotaphrum secundatum) and Zoysiagrass (Zoysia spp.) are popular turfgrasses in the southeastern United States due to their relatively low input requirements compared to cool-season grasses. However, both species lack freeze tolerance and freezing injury occurs during some winters in USDA hardiness zones 8 and 9. In an attempt to address these issues, we have initiated projects to develop populations with improved cold tolerance and turf quality. Approximately 350-500 hybrids are generated each year and planted in nurseries across the state. Promising hybrids are advanced to replicated field trials at multiple locations where they will be compared to commercial checks in order to evaluate their potential as new cultivars. Additionally, progenies from freeze-tolerant x freeze-sensitive cultivars are being genotyped and evaluated for winter survival in an attempt to map genes controlling freeze tolerance. Markers associated with regions controlling this trait could ultimately used in a marker-assisted selection program to expedite the selection process.

This project will focus on building genomic tools for grass species, which as an important southeastern crops have limited tool resources, including genome assembly and annotation. Lab, greenhouse and field experiments will be performed, particularly focused on quality and disease in order to obtain phenotypic information for identifying Quantitative Trait Loci (QTL) and genomic regions associated with traits of interest. Identified genomic regions will be used to begin investigation of genomic regions identified by experiments, using additional samples in lab, greenhouse and/or field experiments.

NCDOT currently has to maintain vegetation under and around over 1000 miles of median rail, with approximately $40 million spent in fiscal year 2019 for mowing. Zoysiagrasses are known to be a thick sod-producing turfgrass that once adequately established are low-growing and have minimal weed invasion. Establishing zoysiagrass along non-irrigated roadside shoulders has proven problematic. Research project 2018-02 evaluated, in a small plot format, several establishment options. Seeding and vegetative establishment employing newly creaed mechanical methodologies were evaluated. In addition, from the NCSU 2017-2018 breeding nursery containing 95 F1 hybrid Zoysiagrasses, 5 experimental (non-released) zoysiagrass selections were evaluated under roadside conditions. A narrow-bladed selection (XZ14069) and wide-bladed selection (XZ14070) are showing promise for roadside applications. Findings from this research need to be expanded to ���������������operational-sized������������������ roadside plots for further evaluation. The outcome of this research will provide NCDOT with information so that they can select the best germplasm for the establishment and long-term maintenance of NC roadsides.

Urban ecosystems are the most rapidly expanding landuse type in the U.S. and where over 82% of people live, work, and play. Warm season turfgrasses are ubiquitous to Southern urban landscapes where, when healthy, they provide valuable services that benefit humans and the environment. Unfortunately, insect pests are frequently abundant and damaging in urban landscapes, which, if unaddressed, rapidly kill lawns. Due to a lack of effective or practical IPM tactics, warm season lawn maintenance professionals rely on insecticides to control pests. Dependence on calendar-based insecticide applications has led to insecticide resistance, secondary pest outbreaks, and environmental contamination. We argue that current cultural practices predisposes warm season lawns to insect attack because they are produced, planted, and maintained as genotypic (cultivar) monocultures. Evidence from other systems and preliminary investigations suggests that increasing plant genotypic diversity reduces pest pressure, promotes natural pest regulation, supports more biodiverse communities, and improves plant quality. To determine the effects of increasing warm season turfgrass cultivar diversity on arthropods and lawns across its distribution in the Southeast, we will conduct a common garden field experiment spanning six USDA Plant Hardiness Zones and nine degrees of latitude. We predict that increasing cultivar diversity will increase plant quality and arthropod biodiversity, and reduce plant pests and their associated long term maintenance costs and risks, ultimately promoting ecosystem health. We will quantify these effects through a combination of field and laboratory experiments over multiple locations and years to develop practical, industry-accepted IPM tactics.

Bermudagrass (Cynodon spp.) is widely used for golf courses, athletic fields, and home lawns in the southeastern United States for its superior turf quality and excellent durability. While the grass is considered to have excellent heat and drought tolerances, bermudagrass is also known to have very poor tolerance to shade. This trait is extremely important for use in residential lawns in North Carolina where trees are dominant as well as on golf courses where shade can often affect tee boxes, fairways, and greens surrounds. Development of shade tolerant bermudagrass culitvars would expand the market for this type of grass. The focus of the present proposal is to screen bermudagrass germplasm recently collected from South Africa for its ability to persist under 63% shade. These materials were collected growing in the wild under heavy shade and no inputs (including irrigation). Thus, evaluating their genetic potential to persist under shade and drought is of critical interest.

The PIs will review the curriculum and course syllabi for three of UNSA������������������s academic programs: Food Science and Technology, Nutrition, and Agronomy. The PIs will provide a complete report that describes the process and final evaluation for each program. Selected NC State Faculty will conduct workshops related to teaching and evaluation good practices.

Both the first and third chairmen of the USGA Green Section recognized that zoysiagrass (Zoysia spp.) was an important acquisition to the US golf market. One of the first observations about zoysiagrass by Monteith was its potential for use on low maintenance areas. However, zoysiagrass use for golf course roughs is sparse. Current breeding efforts are focused on ����������������fairway��������������� and ����������������putting green��������������� zoysiagrass and zoysiagrass germplasm that may be useful for roughs is often discarded by breeders as unacceptable when it may in fact be of tremendous value. Zoysiagrass roughs are amongst some of the most easily played (improving pace of play) and easily managed (few inputs required with excellent weed suppression) of all the species used in golf course roughs. Breeding programs have ����������������coarse-textured��������������� germplasm available that has excellent stress and pest tolerance and fast establishment when managed with no inputs. These coarse Z. japonica genotypes have the ability to offer a superior golf course rough surface with little to no inputs and fewer long-term maintenance costs. Our research team has existing collections of zoysiagrasses collected from unmanaged areas or as part of germplasm collections. These existing collections have not been explored for their potential use, but they offer great promise as a low-input zoysiagrass for golf course roughs. The objective of this research is to evaluate zoysiagrass phenotypes for their performance and playability in multiple climates (warm-arid, warm-humid, transition zone) as a potential grass for golf course roughs and other low-maintenance areas.