International Turfgrass Society Research Journal最新文献

This year 2025, JSTS will celebrate its 53rd anniversary since its founding as Japanese Turfgrass Research Society. I believe it is of great significance at this point to look back on the history of the society, remember the hardships of many predecessors, and think about the future development of JSTS.

In Japan, the school grounds covered with turfgrasses were rare until the 1970s. Starting in the mid-1970s, the national and local governments began to support planting turfgrasses on school grounds. The planted turfgrasses in larger schoolyards remained longer, while those in smaller schoolyards in urban areas disappeared soon after planting. It has often been the case that the governments only provide budgets for the initial planting, not leaving enough for maintenance. Therefore, maintenance work became a heavy burden on teachers and school staff, leading to decades of stagnation of the development of the school turf. Then, the turfgrasses at stadiums began to draw attention due to the opening of the J League in 1993 and Japan and Korea's joint hosting of the FIFA World Cup 2002, making turfgrass planting on schoolyards more popular. Government offices and various organizations joined to support turfgrasses in several ways, making it popular for school children, parents, and residents to participate in the process of planting and taking care of turfgrasses, as well as variety of events to be held on the lawn. Turfgrasses on school grounds ended up building beautiful communities with creative activities and interactions. Before 2000, most turfgrass species were Zoysiagrasses (Zoysia matrella and Z. japonica), while more schools started to use Bermuda grasses (Cynodon spp.), especially Tifway, starting around 2000. Some schools have been overseeded with perennial ryegrass. Until around 2000, most school grounds in Japan were planted with square turfgrass sods, while the use of potted seedlings has now become widespread.

We have collected and analyzed genetic resources of the Zoysia genus and investigated the phylogenetic relationships using DNA markers and genome analysis. On the other hand, we also carried out interspecific hybridization to develop new varieties using the collected genetic resources and have established tissue culture techniques and genetic transformation toward developing state-of-the-art molecular breeding programs of the Zoysia genus. In this article, we will introduce the results of these efforts.

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.

Advancements in digital three-dimensional (3D) imaging technology have enabled precise, high-throughput, and non-destructive phenotyping of plant morphology. In this study, we developed a digital phenotyping system specifically tailored for zoysiagrass (Zoysia species), integrating image-based 3D model reconstruction, machine learning, and computational trait analysis. By employing a structure from motion approach, we reconstructed detailed 3D models of zoysiagrass using four industrial cameras and an automated imaging platform. A machine learning algorithm was applied to accurately isolate plant components from non-plant elements. From these segmented models, we extracted key morphological traits—height, spread area, color, and volume—providing a comprehensive dataset for breeding applications. As a digitally derived trait, volume offers new potential in characterizing plant architecture and assessing yield-related traits non-destructively. Additionally, we developed a small-scale, low-cost prototype system using Raspberry Pi and LEGO-based components, demonstrating the scalability and adaptability of 3D phenotyping systems across various experimental settings and budgets. Although 3D phenotyping under controlled conditions using potted plants is not directly transferable to field-based evaluation, it provides essential, reproducible data that bridge early-stage screening and later field validation in breeding programs. These digital morphological measurements are expected to enhance the precision, repeatability, and objectivity of turfgrass evaluation. As 3D technologies continue to evolve and integrate with genomic and environmental data, digital phenotyping will play an increasingly important role in accelerating turfgrass improvement and promoting data-driven plant breeding.

The seasonal shoot and root growth of Zoysia matrella (L.) Merr. (manilagrass) and Agrostis stolonifera L. (creeping bentgrass) were pictorially analyzed in golf course putting greens in the Kanto region of Japan. Profile samples of shoots and roots were harvested seasonally, washed free of soil, and subsequent observations of tiller, root, and thatch/mat structure were recorded. The seasonal growth cycle of creeping bentgrass was determined as (1) autumn (late September through November)—roots and shoots initiated during the previous spring and summer mature; (2) winter (December through February)—nutrients are stored; (3) early spring (March through April)—growth is more active; (4) spring (May through June)—vigorous growth occurs with initiation of new shoots; and (5) summer (July to mid-September)—parent roots and shoots senesce and are replaced by new shoots and roots. More specifically, summer growth was observed as the initiation of new shoots in June with increasing new shoot development through late July. The peak of tillering and root growth was noted as occurring from late August to early September. Most of the shoots become a single layer of new shoots from late September to early October, and autumn growth begins based on these new shoots. The seasonal growth cycle of manilagrass was determined as (1) spring (late March to late May)—parent shoots and roots senesce, and a new foundation of shoots and roots is built from those produced during the previous autumn and now in active growth; (2) summer (early June to late September)—vigorous shoot growth; (3) autumn (early October to before the first frost in December)—new shoots gradually become independent through replacement of the parent shoots; and (4) winter (first frost to mid-March)—growth is suspended and becomes dormant. An understanding of these seasonal growth cycles can be utilized by golf course superintendents in accordance with their fertilizer and thatch management programs.

Chewings fescue (CF; Festuca rubra L. ssp. commutata Gaudin ‘Leeward’) seed was evaluated for use in golf course divot mixes for Kentucky bluegrass (Poa pratensis L. ‘HGT’) tee surfaces. CF seed is typically quick to germinate and matures as a fine-textured, dark green bunch-type turfgrass. It then functions as a noncompetitive nurse grass in mature Kentucky bluegrass tee surfaces and is considered a low risk for contamination of adjacent Kentucky bluegrass rough areas. Three aspects of divot repair were investigated: (1) adding CF seed to a divot mix; (2) divot mix media; and (3) season of divot repair by creation in spring, summer, or fall. The treatments were considered acceptable only if 50% turf cover was observed within a divot recovery period of ≤56 days (8 weeks). The addition of CF seed to the divot mix was more important than the type of divot mix media used. In the fall, divot mixes without seed were unacceptable and found to have the longest divot recovery times of ≥280 days (10 months) to reach 50% turf cover, given winter dormancy halted divot recovery until spring. In contrast, fall divot mixes that contained CF seed resulted in acceptable divot recovery times of 21–28 days (3-4 weeks) to achieve 50% turf cover.

Creeping bentgrass (Agrostis stolonifera) and colonial bentgrass (A. capillaris) naturally occupy wetter and drier environments, respectively. Hybridization between these species offers valuable insights into drought tolerance and could enhance breeding strategies for developing water-deficit–tolerant bentgrasses. A greenhouse dry-down study was conducted using 52 interspecific bentgrass lines, including two parent cultivars, BCD (colonial bentgrass; drought-tolerant) and Providence (creeping bentgrass; drought-susceptible). The study revealed that the drought-tolerant hybrid plants exhibited more efficient mechanisms for drought stress management, including optimized carbon allocation, reduced oxidative stress, and enhanced water conservation. These plants were able to thrive under stress with lower levels of certain metabolites such as citric acid, malic acid, pyruvic acid, α-ketoglutaric acid, indicating a more efficient drought response compared to the susceptible group.

Silvery thread moss (Bryum argenteum Hedw.) (STM) is a common weed on golf course putting greens. Limited herbicidal options are available for the control of STM. Previous research suggests that certain contact fungicides may have efficacy against STM; therefore, a study was conducted to explore fungicidal options for managing STM on golf course putting greens. The study was conducted in Fayetteville, AR, on a “Pure Eclipse” and “Ninety-Six Two” creeping bentgrass (Agrostis stolonifera L.) green. Every combination of the fungicides chlorothalonil, fluazinam, mancozeb, and thiram was tested, along with carfentrazone-ethyl, an industry-standard herbicide, and a nontreated control for a total of 17 treatments. Treatments including chlorothalonil were the most effective at reducing STM coverage, while the combination of fluazinam + mancozeb + thiram was moderately effective at controlling STM. In a supplemental study conducted in Blacksburg, VA, chlorothalonil greatly reduced moss coverage, while potassium phosphite and fosetyl-Al were ineffective. These results give turfgrass managers an alternative to carfentrazone-ethyl for managing silvery thread moss on their putting greens.