Multi‐location testing increases genetic gains for drought tolerance in zoysiagrass

Zoysiagrasses ( Zoysia spp.) are popular warm‐season turfgrass species for home lawns, landscapes, and golf courses in the southern United States due to their lower input needs. However, persistent drought conditions necessitate the development of new cultivars with reduced irrigation requirements. This research addresses this critical need through a multi‐institutional, collaborative breeding project supported by USDA‐NIFA Specialty Crops Research Initiative grants. The primary objective was to improve drought tolerance in zoysiagrass, bridging a gap in the availability of resilient turfgrasses. Our approach involved multi‐environment testing across the southern United States coupled with advanced phenotyping techniques, including the integration of small unmanned aircraft systems (sUAS) to collect visual (red, green, blue) and multispectral imagery. A regression analysis identified significant genetic gains for turfgrass quality under drought, with a noteworthy 10.4% increment per breeding cycle. This collaboration led to the successful commercialization of several new cultivars—including Brazos™, CitraZoy®, and Lobo™—which consistently outperformed industry standards like Zeon and Palisades in turfgrass quality and drought resistance. These new cultivars exhibit improved establishment rates, disease resistance, and wider geographical adaptability. In conclusion, this research confirms that multi‐institutional collaboration, combined with the strategic adoption of sUAS‐based phenotyping and advanced data analysis, is a powerful and efficient strategy for turfgrass breeding. The successful development and release of these superior cultivars provides environmentally sustainable options for a wide range of applications, offering significant benefits to both producers and consumers by reducing irrigation needs.