Zoysiagrass Cultivars Research Articles

Molecular Genetic Insights into the Stress Responses and Cultivation Management of Zoysiagrass: Illuminating the Pathways for Turf Improvement

Zoysiagrass (Zoysia spp.) and its hybrids are known for their low maintenance requirements and are widely utilized as warm-season turfgrass, which offers considerable ecological, environmental, and economic benefits in various environments. Molecular genetic approaches, including the identification and genetic engineering of valuable gene resources, present a promising opportunity to enhance the quality and performance of zoysiagrass. This review surveys the recent molecular genetic discoveries in zoysiagrass species, with a focus on elucidating plant responses to various abiotic and biotic stresses. Furthermore, this review explores the notable advancements in gene function exploration to reduce the maintenance demands of zoysiagrass cultivation. In addition, we discuss the achievements and potential of contemporary molecular and genetic tools, such as omics approaches and gene editing technologies, in developing zoysiagrass cultivars with desirable traits. Overall, this comprehensive review highlights future strategies that may leverage current molecular insights to accelerate zoysiagrass improvement and further promote sustainable turf management practices.

Suzhi 5: A New Hybrid Zoysiagrass Cultivar with High Shoot Density and Fine Leaf Texture

Suzhi 5: A New Hybrid Zoysiagrass Cultivar with High Shoot Density and Fine Leaf Texture

Rooting Comparison of Zoysiagrass Cultivars in the Greenhouse

Rooting Comparison of Zoysiagrass Cultivars in the Greenhouse

Effects of Glyphosate Applied at Different Times on Dormant Zoysiagrass Cultivars in the Transition Zone

Effects of Glyphosate Applied at Different Times on Dormant Zoysiagrass Cultivars in the Transition Zone

Development of winter hardy, fine‐leaf zoysiagrass hybrids for the upper transition zone

AbstractA 10‐yr, four‐phase collaborative effort among three universities was conducted to develop new hybrid zoysiagrasses (Zoysia spp. Willd.) with improved turf quality, winter hardiness, and pest resistance in comparison to commercial zoysiagrass cultivars, especially ‘Meyer’ (Z. japonica Steud.). In Phase 1, breeding efforts produced 2,858 new progeny that were evaluated for 2 yr across three sites. In Phase 2, only 60 (2%) of 2,858 progeny were selected for advancement to 10 replicated multiyear field trials (Phase 3). Phase 3 revealed 10 promising progeny (assigned DALZ numbers) that required further intensive field and laboratory testing in Phase 4. Phase 4 revealed differences in establishment rate, and DALZ 1701, 1702, 1707, and 1810 had moderate‐to‐good turf performance across seven sites, whereas DALZ 1808 had similar or slightly lower performance. Meyer consistently performed poorly, and ‘Innovation’, a recently released hybrid cultivar, had poor‐to‐moderate performance in comparison to the experimental genotypes, which illustrates the improvements achieved in zoysiagrass breeding in the last 10 yr. Freeze tolerance (LT50, lethal temperature killing 50% of the plants) ranged from −9.8 °C (Diamond) to −14.1 °C (DALZ 1812) with a mean of −12.5 °C. Evidence of large patch [Rhizoctonia solani Kühn, anastomosis Group (AG) 2‐2 LP] in the top 10 DALZ genotypes was 15 to 40% lower than Meyer on several dates. Results indicate that there are multiple genotypes for potential release in the future with improved turf color, winter hardiness, freeze tolerance, large patch resistance, and finer leaf texture suitable for USDA plant hardiness zones ranging between 5b and 8a.

Nitrogen rate and cultivar effects on zoysiagrass putting greens in the transition zone

Zoysiagrasses (Zoysia spp. Willd.) have been predominately used as turfgrass for residential and commercial lawns in addition to golf course fairways and tees due to reduced input requirements compared with bermudagrass (Cynodon spp.). The recent development of fine-textured zoysiagrass cultivars has sparked interest in using zoysiagrass on putting greens. A complete-factorial field experiment was conducted over replicate trials in Knoxville, TN to evaluate the putting green performance and quality of four zoysiagrass cultivars under two nitrogen (N) rates in the transition zone. Four zoysiagrass cultivars (Lazer, M85, Prizm, and Trinity) were treated with either 0.93 or 1.9 g N m−2 every 2 wk over a 16-wk period from June to September in 2020 and 2021. Ball roll distance, surface firmness, and turfgrass color were evaluated weekly. Lazer and M85 consistently provided the greatest ball roll distance and turfgrass color over both seasons, whereas Prizm occasionally exhibited similar performance and color. Lazer produced the firmest greens, whereas Prizm exhibited the softest surface. Trinity had reduced turfgrass color over both years, implying that it should not be used on putting surfaces. The 1.9 g N m−2 rate reduced ball roll distance and increased turfgrass color but had limited effect on surface firmness. Applying 0.93 g N m−2 increased ball roll distance, reduced turfgrass color, and maintained surface firmness similar to 1.9 g N m−2. Additionally, cultivar selection will likely affect putting green performance, playability, and quality.

Inflorescence appearance timing and production rate traits in wild Zoysiagrass (Zoysia spp)

Zoysiagrass (Zoysia spp.) has excellent turf quality and can be applied to various uses for personal space to public sports areas or commercial landscapes. However, it has disadvantages such as slow growth rate, cold hardiness, low seed yield, and hard to establish from seeds, which cannot be improved with agricultural practices. Therefore, breeding a new cultivar as a hybrid could be an efficient strategy to improve the Zoysiagrass cultivar. In fact, hybrid zoysiagrass shows mixed traits of both parents in morphology and heterosis in growth. However, inflorescence appearance and its rate are known to make a hybrid. Thus, the variety of inflorescence appearance timing and production rate were investigated among 549 genetic resources. As a result, only 5.38% of the variety among survived zoysiagrass after transplanting showed more than 30% inflorescence appearance within the given period. During that, some varieties showed a reduction of total inflorescence. Hence, we report the diversity of inflorescence appearance timing and production rate that could be useful for breeders and researchers breeding new Zoysiagrass cultivars.

Development of ‘Halla Green 7’: A Zoysiagrass Cultivar with Greening Period Extending Phenotype at Lower Temperatures

Development of ‘Halla Green 7’: A Zoysiagrass Cultivar with Greening Period Extending Phenotype at Lower Temperatures

Dormant Sprigging of Bermudagrass and Zoysiagrass

Many bermudagrass (Cynodon sp.) and zoysiagrass (Zoysia sp.) cultivars are not available as seed and are commonly planted vegetatively using sprigs, especially for sod production or in sand-based systems. Sprig planting is typically done in late spring or early summer, but this can result in an extended grow-in period and delay the use of the turf in the first growing season. The objective of this study was to determine if sprigs of bermudagrass and zoysiagrass could be planted earlier in the year, during the dormancy phase, to hasten establishment. A field study was carried out in Fayetteville, AR, in 2014 and 2016 using ‘Tifway’ hybrid bermudagrass (Cynodon dactylon × Cynodon transvaalensis) and ‘Meyer’ zoysiagrass (Zoysia japonica), and in Guangzhou, China, in 2015, using ‘Tifway’ hybrid bermudagrass and ‘Lanyin III’ zoysiagrass (Z. japonica). Sprigs were planted in March (dormant), May (spring) and July (summer) in Fayetteville, and in January (dormant), March (spring) and May (summer) in Guangzhou. Sprigging rates of 30, 60, and 90 m3·ha−1 were tested at both locations and across all planting dates. Bermudagrass was less affected by planting date, with dormant, spring or summer plantings effectively establishing full cover in the first growing season. Zoysiagrass that was sprigged in the dormant season was successfully established by the end of the first growing season while a full zoysiagrass cover was not achieved with either spring or summer plantings in Arkansas. Dormant sprigging reached full coverage as fast or faster than traditional spring or summer planting dates at both locations, indicating that bermudagrass and zoysiagrass establishment can be achieved earlier in the growing season using dormant sprigging methods.

Daily light integral requirements for bermudagrass and zoysiagrass cultivars: Effects of season and trinexapac‐ethyl

AbstractShade is a major problem facing turf managers worldwide. Availability of low‐cost devices and methods for quantifying daily light integral (DLI) offer the turf manager the ability to more precisely determine DLI levels in shade, yet minimal DLI requirements for acceptable turf quality (DLIm) for many commonly used warm‐season turf cultivars grown under longer‐term chronic shade stress have not been extensively tested. The objectives of this 2‐yr field shade study were to (a) determine effects of growth regulator trinexapac‐ethyl (TE) and season (summer or fall) on DLIm of nine commercially available bermudagrass (Cynodon spp.) and zoysiagrass (Zoysia spp.) cultivars; (b) determine effects of shade level and TE on summer percent green cover and root growth; and (c) determine effects of shade treatments on soil temperatures across the growing season. Significantly higher DLIm were noted during summer compared to fall for all cultivars in the study. The DLIm were generally higher for bermudagrass than zoysiagrass cultivars. ‘Tifway’ required the highest DLIm (ranging from 23.5 to 27.2 mol m−2 d−1) of the bermudagrasses. ‘TifGrand’, ‘Celebration’, and ‘Latitude 36’ showed comparable DLIm during summer and fall. Fewer consistent differences were detected between zoysiagrasses, with ‘Zorro’ and ‘Zeon’ showing the lowest summer DLIm (18.1 and 19.1 mol m−2 d−1, respectively) and ‘Geo’ showing the lowest fall DLIm (11.7 mol m−2 d−1). Trinexapac‐ethyl reduced DLIm only in Zorro, ‘Palisades’, and ‘JaMur’ zoysiagrass, but had no effect on bermudagrass DLIm. The DLIm for a number of cultivars were higher than those previously reported in the literature, which may be attributed to lower mowing heights and/or use of permanent shade structures that were not removed for the duration of the 27‐mo study. The findings should benefit turf managers by guiding data‐driven, seasonal‐based, warm‐season turfgrass cultivar selection for shaded environments.

Identification of QTL associated with cold acclimation and freezing tolerance in Zoysia japonica

AbstractZoysiagrasses (Zoysia spp.) are relatively low‐input and warm‐season turfgrasses which have grown in popularity in the United States since their introduction in the 1890s. Over 30 improved zoysiagrass cultivars were released in the past three decades, but many lack freezing tolerance and their use is limited to warm‐humid climates. Understanding the genetic controls of winter hardiness and freezing tolerance in zoysiagrass could considerably benefit the breeding efforts to increase tolerance to freezing stress. In the present study, controlled environment acclimation and freezing tests were used to evaluate a Meyer × Victoria zoysiagrass mapping population for post‐freezing surviving green tissue (SGT) and regrowth (RG). Quantitative trait loci (QTL) mapping analysis identified nine QTL associated with SGT, eight QTL linked to RG, and 22 QTL common in both traits, accounting for between 6.4 and 12.2% of the phenotypic variation. Eleven regions of interest overlapped with putative winter injury QTL identified in a previous field study. Upon sequence analysis, homologs of several abiotic response genes were found underlying these overlapping QTL regions. The homologs of these gene encode transcription factors, cell wall modification‐related proteins, and defense signal transduction‐related proteins. After further validation, these QTL and their associated markers have potential to be used in future breeding efforts for the development of a broader pool of zoysiagrass cultivars capable of surviving in cold climates.

Relative Traffic Tolerance of Warm-Season Grasses and Suitability for Grazing by Equine

Warm season wear-tolerant turfgrasses, such as those used on golf courses and athletic fields, may be valuable forages on equine operations because of their potential to remain viable during heavy hoof traffic. Crabgrass may also be suitable as it thrives in conditions where other grasses have limited success. The objective of this study was to assess the relative traffic tolerance and nutritional composition of five warm-season (WS) turfgrass cultivars of bermudagrass and zoysiagrass and one WS forage-type crabgrass. All cultivars were established by seed in replicated monoculture plots. Simulated hoof traffic treatments consisted of either none, one, or two passes of a Baldree Traffic Simulator. Traffic was applied weekly for 6 weeks in the summer of 2016 and 2017, with each treatment period followed by a 4-week rest period. Plots were assessed for compaction, biomass, and persistence before and after treatment and rest periods. Nutritional composition was assessed throughout the growing seasons. Soil compaction increased as treatment level increased for all cultivars (P < .0001). There was no effect of treatment on cultivar persistence. Biomass available for grazing was increased in year 1 by the application of LOW traffic treatment (P = .0193). Both bermudagrass and zoysiagrass cultivars showed promise for use in areas of heavy traffic on equine operations, however, zoysiagrass cultivars were more suitable as they were highest ranking in relative traffic tolerance, moderate in yield, and low nonstructural carbohydrates (<12% NSC). Future on-farm studies evaluating bermudagrass and zoysiagrass to determine ideal stocking rate, management methods, and persistence under grazing are warranted.

Salinity Tolerance and Recovery Attributes of Warm-season Turfgrass Cultivars

As population growth places greater pressures on potable water supplies, nonpotable recycled irrigation water is becoming widely used on turfgrass areas including golf courses, sports fields, parks, and lawns. Nonpotable recycled waters often have elevated salinity levels, and therefore turfgrasses must, increasingly, have good salinity tolerance to persist in these environments. This greenhouse study evaluated 10 commonly used cultivars representing warm-season turfgrass species of bermudagrass (Cynodon spp.), zoysiagrass (Zoysia spp.), st. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and seashore paspalum (Paspalum vaginatum Swartz) for their comparative salinity tolerance at electrical conductivity (EC) levels of 2.5 (control), 15, 30, and 45 dS·m–1. Salinity treatments were imposed on the grasses for 10 weeks via subirrigation, followed by a 4-week freshwater recovery period. Attributes, including turf quality, the normalized difference vegetation index (NDVI), canopy firing, and shoot biomass reductions were evaluated before and after salinity stress, as well as after the 4-week freshwater recovery period. Results showed considerable differences in salinity tolerance among the cultivars and species used, with the greatest tolerance to elevated salinity noted within seashore paspalum cultivars and Celebration® bermudagrass. In comparison with growth in 2.5-dS·m–1 control conditions, increased shoot growth and turf quality were noted for many bermudagrass and seashore paspalum cultivars at 15 dS·m–1. However, st. augustinegrass and some zoysiagrass cultivars responded to elevated salinity with decreased growth and turf quality. No cultivars that had been exposed to 30- or 45-dS·m–1 salinity recovered to acceptable levels, although bermudagrass and seashore paspalum recovered to acceptable levels after exposure to 15-dS·m–1 salinity. More severe salinity stress was noted during year 2, which coincided with greater greenhouse temperatures relative to year 1.

Effects of close cutting on ground cover and quality of a polystand of Manilagrass and cool season turfgrasses

Warm season turfgrasses can be grown successfully in the transition zone, but dormancy occurs to some extent during the winter. Overseeding with cool-season turfgrasses is necessary if winter dormancy of warm season turfgrasses is not tolerated. The increasing availability of zoysiagrass cultivars has enabled this genus to be considered suitable for low-maintenance golf courses, especially for golf tees and golf fairways. On the other hand, zoysiagrasses have the most rigid leaves of all turfgrass species, followed by bermudagrasses and by the other warm season turf species. Thus, to have a high mowing quality, mowers working constantly on zoysiagrasses require more sharpening than mowers working on other grasses. Rotary mowers are not suitable for mowing at low heights and often result in scalping, while reel mowers perform optimal mowing at a short height (below 2.5 cm) but require accurate management and frequent sharpening. Autonomous mowers have proven to produce a superior turf quality compared with traditional walk-behind rotary mowers, but no autonomous mower has ever been tested at a low mowing height on an overseeded warm season turfgrass. Because of this, the trial was carried out to simulate a golf tee overseeded with cool season turfgrasses, with low input fertilisation rates and with one of the most difficult turf species to mow; i.e. Zoysia matrella (L.) Merr. The trial was carried out in San Piero a Grado (Pisa, Italy) from October 2016 to October 2018. After a two-year period the best turf quality was achieved with Festuca rubra L. ssp. cultivars among the overseeded species, especially during fall. In many cases turf quality increased after manila grass green up since the combination of both cool season and warm season species gave a higher quality to the turfgrass, due to the finer leaf texture and higher shoot density of some cool season species. Moreover, recovery of manila grass ground cover was satisficing. In conclusion, a polystand of manila grass and Festuca rubra ssp. could be suitable for golf tees with low-input management.

Correlating Methods of Measuring Zoysiagrass Thatch

In the absence of regular management, zoysiagrass (Zoysia spp.) thatch can be problematic and result in unacceptable turf quality. At least three methods of measuring thatch are used in turfgrass science, including organic matter percentage by weight‐loss‐on‐ignition (WLOI), depth by ruler, and mass by balance. The objective of this study was to determine if thatch compression using the faster Volk “thatchmeter” correlated to the three abovementioned methods. The four methods were evaluated as part of a field study designed to determine the influence of fertility and cultural management practices on thatch development of five zoysiagrass cultivars. Treatments were verticutting, topdressing, and fertilization arranged in a split‐split‐plot design with three replications. Thatch measurements were collected approximately every other month from June to November during three consecutive growing seasons in Jay, FL. The thatchmeter resulted in lower F values on Zoysia japonica Steud. than on Z. matrella (L.) Merr. Cultivars, indicating that the instrument had reduced sensitivity on the higher cut Z. japonica cultivars. Linear regression of the thatchmeter and the WLOI, ruler, and mass measurements resulted in 80% of the R2 values being &lt;0.1. The increase in turf leaf blades likely contributed to the reduced sensitivity of the thatchmeter on Z. japonica cultivars. Although the thatchmeter sensitivity increased on the Z. matrella cultivars, the instrument failed to correlate to WLOI, ruler, or balance measurements.

Nitrogen Rate and Mowing Height Affect Seasonal Performance of Zoysiagrass Cultivars

Core Ideas Nitrogen rate had a greater impact on turfgrass quality of zoysiagrass when the grass was actively growing, but the effect of mowing height was only significant during spring green‐up. Nitrogen rate of 171 kg ha−1 was suitable for consistent turf performance in zoysiagrass and the effect of increasing N rate from 171 to 268 kg per ha was minimal. Japanese lawngrass and manilagrass can be successfully maintained at 2.5 or 5.0 cm and 0.6 or 1.2 cm, respectively, for equivalent performance during the majority of the year; however, during spring green‐up, the lower mowing height may deliver better turf performance. As new zoysiagrass (Zoysia spp.) cultivars are released, field studies on N responses and mowing heights conducted over several years under different environments are needed to determine best management practices. This study was initiated to (i) characterize a general response (color, density, turf quality) to N fertilization rate, mowing height, and their interactions among zoysiagrass cultivars; and (ii) establish appropriate mowing height and N rate recommendations for each of the cultivars studied. Four Japanese lawngrass cultivars (Z. japonica Steud.) and four manilagrass cultivars (Z. matrella L. Merr.) were evaluated in Citra, FL, for 4 yr and in Raleigh, NC, for 2 yr under three N rates (73, 171, and 268 kg ha−1 yr−1) and two mowing heights (2.5 and 5.0 cm for Japanese lawngrass; 0.6 and 1.2 cm for manilagrass). Genetic differences were evident among the zoysiagrass cultivars. Nitrogen rate had a greater impact on most of the observed characteristics when the grass was actively growing, but the effect of mowing height was only significant during spring green‐up. The medium N rate was suitable for consistent turf performance throughout the year and the effect of increasing N rate from 171 kg ha−1 to 268 kg ha−1 was minimal. Japanese lawngrass and manilagrass can be successfully maintained at 2.5 or 5.0 cm and 0.6 or 1.2 cm, respectively, for equivalent performance during the majority of the year. However, during spring green‐up, the lower mowing height may deliver better turf performance.

Turf Quality Trait and Genetic Fingerprinting of a New Zoysiagrass Cultivar in Japan

Turf Quality Trait and Genetic Fingerprinting of a New Zoysiagrass Cultivar in Japan

Hormone and Dehydrin Expression Responses to Cold Acclimation in Two Zoysiagrass Cultivars with Contrasting Freezing Tolerance

Zoysiagrass (Zoysia spp.), a warm‐season turfgrass genus, is subjected to freezing damage in the US transition zone and other similar climate regions. This study was designed to investigate changes in hormones and dehydrin expression in responses to cold acclimation (CA) in two zoysiagrass cultivars. Two zoysiagrass cultivars (‘Meyer’, cold tolerant; ‘Cavalier’, relatively cold sensitive) were subjected to either CA (8/4°C day/night and a photosynthetically active radiation of 250 μmol m−2 s−1 over a 10‐h photoperiod) or no CA in growth chambers for 28 d. Cold‐acclimated Meyer had greater overall freezing tolerance (stolon temperature resulting in 50% survival [LT50] = −15.4°C) than cold‐acclimated Cavalier (stolon LT50 = −8.2°C). Leaf abscisic acid (ABA) content increased and cytokinins (trans‐zeatin riboside and isopentenyl adenosine) declined during CA. Cold‐acclimated Meyer accumulated higher levels of ABA but less cytokinins relative to cold‐acclimated Cavalier. Leaf ABA content was 37% higher in cold‐acclimated Meyer than in cold‐acclimated Cavalier at 28 d. Meyer had higher levels of indole‐3‐acetic acid than Cavalier. Cold acclimation induced dehydrin (12, 23, and 65 kDa) expression in leaf tissues of both cultivars. Cold‐acclimated Meyer had greater abundance of the dehydrins (12, 23, 30, and 35 kDa) in stolon tissues and in leaf tissues (12, 30, and 65 kDa) than cold‐acclimated Cavalier. The results of this study suggest that higher levels of ABA and certain dehydrin expression and lower levels of cytokinins during CA may be associated with freezing tolerance in zoysiagrass.

Ecological Implications of Zoysia Species, Distribution, and Adaptation for Management and Use of Zoysiagrasses

The genus Zoysia Willd. comprises ±10 recognized species indigenous to the western Pacific Rim and Indian Ocean, which are collectively called “zoysiagrasses.” Three species—Z. japonica Steud., Z. matrella (L.) Merr., and Z. pacifica (Goudswaard) M. Hotta &amp; Kuroki (previously referred to as Z. tenuifolia)—plus interspecific hybrids have a long history of use as warm‐season perennial turf and ornamental grasses in many countries. Recently, cultivars from two other species, Z. macrantha Desv. and Z. sinica Hance, have also been developed. Breeders are currently exploring the potential to incorporate attributes from these and other Zoysia species into future zoysiagrass cultivars through hybridization. The attributes of Zoysia turfgrass cultivars—their strengths and limitations—can be related back to the species and germplasm from which they have been derived, and which (together with growth and development characteristics unique to the zoysiagrasses) ultimately determine their adaptation, use, and management. Differences in temperature, shade, drought, salinity, and traffic tolerance, as well as differences in nutritional and mowing requirements among zoysiagrasses, plus comparisons with Cynodon spp. turfgrasses, are highlighted.

SSR Allelic Diversity Shifts in Zoysiagrass (Zoysia spp.) Cultivars Released from 1910 to 2016

Selection during varietal improvement has been shown to reduce genetic diversity in several different crop species. A reduction in genetic diversity can be detrimental to future breeding efforts and increase susceptibility to biotic stresses. The purpose of this study was to analyze changes in levels of allelic diversity at the gene and population levels in 40 zoysiagrass (Zoysia spp. Willd.) cultivars released between 1910 and 2016 using simple sequence repeat (SSR) markers. Fifty‐six SSR primer pairs were used to determine whether allelic diversity has changed among cultivars released over a century of modern plant breeding. While no significant differences were observed for total numbers of alleles or genetic similarity values between the initial and most recent time periods, our results demonstrate that genetic diversity among zoysiagrass cultivars has fluctuated over time. Allelic diversity declined during the 1990s and then recovered during 2000s. STRUCTURE analysis revealed five subpopulations with varying levels of admixture and that, for the most part, good representation of these subpopulations has been maintained over the different decades of release. These findings illustrate that plant breeding has not resulted in a substantial decline in zoysiagrass genetic diversity, but also that the potential exists for increasing diversity through future germplasm collections and the inclusion of less‐used Zoysia species to create new combinations of alleles.