IMPROVEMENT AND MANAGEMENT OF TURFGRASSES FOR WINTER COLOR RETENTION, WATER CONSERVATION, SALINITY RESISTANCE, AND ENCROACHMENT OF POA ANNUA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1019379
• Project Start Date: May 17, 2019
• Project End Date: Sep 30, 2023
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF CALIFORNIA, RIVERSIDE
(N/A)
RIVERSIDE,CA 92521

Performing Department
Botany and Plant Sciences

Non Technical Summary
Turfgrass is the largest irrigated crop in the United States and a multi-billion dollar industry in California. However, increasing drought frequency and diminishing fresh water resources are jeopardizing the future of turf and its benefits to recreation, urban culture, the environment, and the economy. Conventional breeding and molecular biology are being used to develop warm-season turfgrass species for improved winter color retention and drought resistance leading to water conservation in California and the Southwest. Rising costs of potable water are forcing turf facilities to explore non-potable water sources for irrigation. Poor water quality and/or salt accumulation due to prolonged periods without rainfall pose salinity issues for turf managers. Commercial products and cultural management strategies are being evaluated to further conserve water resources and resist deleterious effects of salinity on turfgrass management. California's Mediterranean climate is ideal for annual bluegrass (Poa annua). However, under intensive management this species is highly susceptible to several biotic and abiotic stresses including heat/drought/cold, disease, and nematodes. As a result, a growing number of golf courses are resorting to conversion to creeping bentgrass, which has better stress tolerance and putting traits (e.g., no seedheads under low mowing). The challenge facing golf course superintendents in California and abroad is keeping annual bluegrass from re-infesting new bentgrass greens. In California especially, the window of Poa germination and infestation is much broader compared to other regions. Currently, plant growth regulators (PGRs) are used for Poa suppression, but they cannot be used year round due to temperature constraints. Cumyluron and methiozolin are two new herbicides currently under development in the U.S. for selective control of annual bluegrass in bentgrass putting greens and other turf areas. Research is ongoing to understand and optimize use of these herbicides in California and southwestern U.S.

Animal Health Component

80%

Research Effort Categories

Basic

10%

Applied

80%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
103	0210	1020	20%
111	0210	1020	20%
213	2130	1140	20%
201	0210	1081	40%

Knowledge Area
103 - Management of Saline and Sodic Soils and Salinity; 111 - Conservation and Efficient Use of Water; 201 - Plant Genome, Genetics, and Genetic Mechanisms; 213 - Weeds Affecting Plants;

Subject Of Investigation
2130 - Turf; 0210 - Water resources;

Field Of Science
1081 - Breeding; 1140 - Weed science; 1020 - Physiology;

Keywords

turfgrass

turf

drought

salinity

weed

herbicide

water

bermudagrass

cynodon

annual bluegrass

poa annua

poa reptans

Goals / Objectives
Turfgrass is the largest irrigated crop in the United States and a multi-billion dollar industry in California. However, increasing drought frequency and diminishing fresh water resources are jeopardizing the future of turf and its benefits to recreation, urban culture, the environment, and the economy. Rising costs of potable water are forcing turf facilities to explore non-potable water sources for irrigation. Poor water quality and/or salt accumulation due to prolonged periods without rainfall pose salinity issues for turf managers. California's Mediterranean climate is ideal for annual bluegrass (Poa annua). However, under intensive management this species is highly susceptible to several biotic and abiotic stresses including heat, drought, cold, disease, and nematodes. As a result, a growing number of golf courses are resorting to conversion to creeping bentgrass, which has better stress tolerance and putting traits (e.g., no seedheads under low mowing). The challenge facing golf course superintendents in California and abroad is keeping annual bluegrass from re-infesting new bentgrass greens. In California especially, the window of Poa germination and infestation is much broader compared to other regions. Currently, paclobutrazol and flurprimidol are used for Poa suppression, but these PGRs cannot be used year round due to temperature constraints. Cumyluron (Marubeni Corp., Japan) and methiozolin (Moghu Research Center, South Korea) are currently under development in the U.S. for selective control of annual bluegrass in bentgrass putting greens and other turf areas, and California is at the forefront of this research. The specific goals of this project are:1. Develop bermudagrass turf-type genotypes with improved winter color retention and drought tolerance for Mediterranean and arid climates.2. Utilize Diversity Arrays Technology (DArT) markers to aid in breeding efforts and marker-assisted selection.3. Evaluate commercial and experimental products for alleviating soil salinity and stress on annual bluegrass putting green turf irrigated with saline water.4. Evaluate commercial and experimental fungicides for the control of rapid blight on annual bluegrass greens.5. Evaluate a select number of commercial products purported to save water, at varying rates, on bermudagrass turf subjected to 45, 55, and 65% ET0 irrigation replacement.6. Determine the most cost effective product(s) that result in demonstrable irrigation water savings.7. Evaluate effective application timing and total active ingredient of cumyluron and methiozolin required to provide effective preemergence and postemergence control of annual bluegrass in creeping bentgrass putting greens in northern and southern California.8. Determine the basis for methiozolin herbicide selectivity on tolerant and susceptible creeping bentgrass cultivars and annual bentgrass biotypes.

Project Methods
Bermudagrass is commonly used throughout the southern U.S. and is considered the "go to" warm-season species for many golf courses in California. Its major disadvantage is winter dormancy. For this purpose we established a collection of all six Cynodon species in Riverside, by requesting samples from the USDA and several other sources. At present the collection exceeds 100 accessions; all six species are represented by at least several genotypes each. We started intercrossing these species and generated a large number of interspecific hybrids, whichshow variation for every observable characteristic, including the onset of winter dormancy and spring green-up.Our immediate plans are to attempt to intercross the hybrids with latest dormancy and the earliest green-up, on the assumption that the next generation hybrids may show reduced dormancy period. In the meantime, the best-looking hybrids are being tested in various environments throughout California, Arizona, and Nevada.In addition, a separate area of these grasses were established at UCR and, once established, irrigation was turned off to evaluate relative drought tolerance. New sets of hybrids are also being generated, again by open pollination of selected collection accessions. Presently we are expanding these grasses for further evaluations in larger plots (for more realistic cultural care and better evaluation of quality characteristics) across several climatic zones in California and the Southwest.To establish the parentage of the existing hybrids, the collection and a sample of hybrids were genotyped using DArT technology (Baird et al., 2012). Species-specific markers show quite clearly the parental contribution and thus this technology will prove valuable to our project.A research putting green was constructed at UCR in 2019. The green was seeded with Poa reptans 'Two Putt', a perennial biotype of annual bluegrass.Saline water will be made by mixing salts in potable water within two 5000-gal storage tanks containing submersible pumps for mixing and agitation. Total salinity (EC ≈ 2.0 dS/m) of the water was chosen to simulate an extreme, but realistic irrigation salinity for turf in California.Plots will be irrigated by hand with saline water (2.0 dS/m).Twelve salinity alleviation and 12 fungicide treatments including untreated controls will be replicated inside each 30-ft x 30-ft area and applied every 1, 2, or 4 weeks from June thru October. Every 2 weeks plots will be evaluated for turf quality, volumetric soil water content (VWC) and ECe using POGO, and Normalized Difference Vegetative Index (NDVI) and Dark Green Color Index (DGCI) using Digital Image Analysis. Leachate will also be collected from suction lysimeters and analyzed for ECL. Furthermore, fungicide treated plots will be evaluated for disease cover and turf quality, turf injury and turf cover at weekly basis. At the end of the study (November), soil samples will be taken for complete nutrient and salinity analysis.The study will be conducted in 2019 and 2020 at the UC Riverside turfgrass research facility in Riverside, CA on mature hybrid bermudagrass 'Tifway II' established in 2017. UCR is the warmest and driest campus in the U.S. where turfgrass research can be conducted. Soil is a Hanford fine sandy loam. The 60' x 90' field was divided into 12 20' x 20' plots. From May 23 thru October each year, the plots will receive 45, 55, or 65% of previous week reference short crop evapotranspiration (ETos) by hand watering to maximize water distribution uniformity as determined by an on-site CIMIS station. Treatments will be arranged in a split-plot design with twelve wetting agent treatments (plot size 24 ft2) randomized within ETos replacement plots and 4 replicates. Treatments will be applied according to company recommendations beginning in May each year. As many as 10 wetting agents or a smaller number applied at different rates will be tested against an untreated control and one Revolution plot that will serve as "UCR standard". The study will receive 5 lb N/M/year and will be mowed at ½ in. Treatments will be applied using a CO2-powered hand boom sprayer equipped with TeeJet 8004VS nozzles and output of 2 gal/M. All treatments will be irrigated with ca. 1/3-in of water following application. Every two weeks, plots will be evaluated for turf quality on a scale from 1 = worst to 9 = best, Normalized Difference Vegetation Index (NDVI) using a GreenSeeker instrument, volumetric soil water content (VWC) using time domain reflectometry (TDR), and dark green color index (DGCI) as well as percent cover using Digital Image Analysis (DIA). Leaves samples will be collected monthly from May until October to determine proline content in the tissues. Visual turf quality and % green cover using DIA will also be taken to measure the effect of fertilizer products on bermudagrass dormancy and green-up in late fall and early spring. Data will be subjected to analysis of variance (ANOVA). When necessary, multiple comparisons of means will be assessed using Fisher's protected least significant difference test at the 0.05 probability level.Studies will be conducted on golf courses with newer creeping bentgrass putting greens where encroachment of Poa annua has begun. Herbicides and standard PGR comparisons will be applied at 1/2x, x, and 2x rates at various times of the year to evaluate Poa control and bentgrass injury. Experimental design will be a randomized block with 4 replications. Plot size will be 4 ft x 6 ft with 2-ft alleys between rows. Treatments will be applied using a CO2-powered backpack boom sprayer with TeeJet 8003 flat fan nozzles calibrated for 2 gal/1,000 ft2 spray output. Treatments will be irrigated with 0.02 inches (cumyluron) or 0.1 inches (methiozolin and PGRs) of water immediately following each application. Visual annual bluegrass cover and bentgrass phytotoxicity (0-100%) will be assessed bi-weekly during the studies. Rootzone samples will be collected for root mass and/or winRhizo analyses periodically during the experiments to determine herbicide effects on bentgrass root growth. Data will be subjected to analysis of variance (ANOVA). When necessary, multiple comparisons of means will be assessed using Fisher's protected least significant difference test at the 0.05 probability level.Annual bluegrass is a difficult to control weed, infesting creeping bentgrass greens, therefore causing the decrease in aesthetics and playability. Methiozolin is a new isoxazoline herbicide that selectively controls annual bluegrass in desirable turf. It is currently undergoing USEPA registration. Previous reports indicated that the herbicide is most active with root exposure. Turfgrass species differ in susceptibility to this herbicide, but there is also variability within species. Creeping bentgrass 'Pure Distinction' is known to be tolerant to methiozolin, though it can still show injury with this herbicide especially, when exposed to high temperatures, causing disturbance and/or damage of functionality of deeper roots. The aim of this research is to evaluate and compare the effect of methiozolin used as a foliar application followed by irrigation on injury of annual bluegrass (Poa annua) 'Two Putt' and creeping bentgrass (Agrostis stolonifera) 'Pure Distinction' plants. In a greenhouse study, each species will be subjected to root zone severance at various depths (50 mm, 100 mm, 150 mm compared to uncut roots at 200 mm). An attempt to determine the impact of methiozolin on metabolism will also be performed. Better understanding of the mechanism of methiozolin impact on target weed and desirable plant species, as well as identification of key factors affecting plant susceptibility to the herbicide is crucial and should result in more accurate usage of the herbicide.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? 1.As in previous years, new hybrids are being produced; in 2020 864 new hybrids were planted. They are being screened for color retention and turf quality, together with collection accessions and 1634 hybrids planted in previous years. Based on this evaluation, 48 hybrids were selected for further testing in larger plots at a fairway mowing height, 19 hybrids for roughs/lawns and six for greens. These hybrids are currently propagated for establishment in test plots next year. Top performing collection accessions were again intercrossed in 2020 (detached tiller crosses). Dry-down tests continued in 2020. This study includes 71 best hybrids and collection accessions identified in previous years, together with five commercial cultivars ('Bandera', 'Celebration', 'Santa Ana', 'TifTuf' and 'Tifway II') as checks. Plots were established in May 2019, in a completely randomized design with three replicates. Two cycles of drought and recovery were performed in 2020. The results from 2019 and 2020 indicate high drought tolerance of several UCR hybrids. While high variation between the years was observed, many of our hybrids performed better in both years than the checks. The best UCR hybrids, ranking in top 10 in both years, were UCRC180040 and UCRC180229. The best commercial cultivar in both years was 'Celebration'. Some hybrids appeared to be "primed" to respond to future stress, going dormant quicker in the second cycle. The study of suitability of 12 UCR bermudagrass hybrids and three commercial cultivars for roughs and homeowner use, planted in 2019, continued in 2020.Based on performance in previous and ongoing studies, 17-8 and TP 6-3 were selected to be released as commercial cultivars. Additional data on their morphological and other characteristics are currently being collected. 2. SeePudzianowska, M., Baird, J.H. 2020.Genetic diversity and species-specific DNA markers ofCynodonRich. Crop Science. p.1-32.https://doi.org/10.1002/csc2.20369 3 and 4.Soil EC was elevated from ca. 0.2 dS/m prior to saline irrigation to 0.8 dS/m by late September 2020 shortly after irrigation salinity was increased to 4 dS/m; however; none of the treatments resulted in statistically significant differences in soil EC to date. It has proven very difficult to raise soil salinity of a sand-based root zone with ideal drainage, and thus reconstruction should be considered a major (albeit costly) management tool for salinity on putting greens.Without producing critical soil EC levels due to optimal drainage, no signs of Labyrinthula terrestris, the causal agent of rapid blight disease, have been detected thus far. Furthermore, none of the treatments caused injury to annual bluegrass turf. The only significant treatment differences were observed during extended periods of record-breaking high temperatures above 100F between August 24 and September 8, including a high of 117F on September 5. Thus far, it appears that weekly applications of treatments composed primarily of nutrients have had the greatest positive impact on turf quality, color, and cover. Specifically, treatments 19 (Brandt weekly fertilizer rotation with Daconil Action), and 18 (Brandt weekly fertilizer rotation) have produced the highest ratings. However, it should be pointed out that all of the treatments produced better results than the untreated control on most rating dates even though statistical differences were not always evident. Other treatments that ranked near the top for most ratings included (in no particular order): 21 (Harrell's tank-mix of Daconil Action, Activator + Salicylic acid, Fleet 100, and an experimental product); 2-4 (Locus Ag treatments); 7 (Ocean Organics tank mix); 16 (Brandt's biweekly tank-mixed mixed of fertilizer 1); 17 (Brandt's biweekly tank-mixed mixed of fertilizer 2); and 11 (Velista rotated with a tank mix of Appear II and Secure Action).Our research on salinity management is aiming to identify component products that ultimately will be combined in a comprehensive program to combat salinity stress and rapid blight disease. 5 and 6.Civitas products often showed improvement in turf quality and color, especially when the product was applied one week before plots were evaluated. Minor differences were recorded among the two rates. For the wetting agent treatments, the reduced vs. full rate showed no differences with Hydro-Inject and only minor differences with Passage at the 4-week application frequency. All tested products could maintain acceptable quality for at least 12 weeks when irrigated at 55% ETo replacement, better than the untreated control. This trial will continue to be evaluated until late October 2020. The same study is being replicated at the Ft. Lauderdale Research & Education Center, University of Florida. 7 and 8.Eleven studies were initiated on golf course putting greens and on a green at the University of California, Riverside turfgrass research facility in 2019-20. Overall, no significant injury to creeping bentgrass was observed following cumyluron application rates ranging from 1.5-12 oz./1,000 ft 2 . Occasionally, turf discoloration occurred when applications were made during periods of warmer weather and this phenomenon was not rate dependent (i.e., appeared similar for all rates); however, discoloration usually subsided by the next scheduled application in spring or fall. One extraordinary situation that resulted in severe injury from higher rates (6 and 12 oz) of cumyluron occurred at Los Angeles CC. Approximately one month after the spring 2020 applications, water was inadvertently withheld from the nursery green where the study is located for approximately one week during warm weather. When irrigation was restored, injury was far greater in cumyluron plots compared to either PoaCure or Bensulide and lasted until the most recent fall applications in December 2020. Studies at North Ridge CC in Sacramento and Bel-Air CC in Los Angeles were conducted on new greens with no Poa invasion to evaluate the true preemergence effects of herbicide treatments. No Poa has been observed in either research area to date. Cumyluron is being tested on the primary practice putting green at The Olympic Club in San Francisco and on three putting greens at Martis Camp GC in Truckee. These greens had very little Poa to begin with and even lower populations have been observed after two applications. Studies in Bend, Oregon have revealed decreasing Poa populations at Crosswater GC when initial populations were less than 10%; however, at Pronghorn initial populations were 30-40% and only the 12 oz rate of cumyluron has caused an appreciable reduction in Poa thus far (data not shown). Similar results have been observed at Anthem CC in Henderson, Nevada. Just two applications of cumyluron at the 6 and 12 oz. rates have resulted in significantly less Poa compared to the control and higher but not significantly different populations compared to PoaCure. The most effective use of cumyluron appears to be on greens with Poa populations less than 10% as evidenced by a separate ongoing study at Martis Camp GC (Table 3). Only two applications at either 6 or 12 oz. have completely eliminated Poa in the plots. A similar trend is being observed at The Bridges at Rancho Santa Fe.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: UCR Turfgrass & Landscape Research Field Day Booklet. 2020. 69 pp.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Schiavon, M., Orlinski, P., Petelewicz, P., Pudzianowska, M., & Baird, J. H. 2019. Effects of Trinexapac?Ethyl, Surfactant, and Nitrogen Fertilization on Bermudagrass Water Use. Agronomy Journal, 111(6), 30573066. https://doi.org/10.2134/agronj2019.03.0225
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Schiavon, M., Mock, T., Stowell, L. J., & Baird, J. H. 2020. Management practices for optimal kikuyugrass quality and playing conditions. Agronomy Journal. https://doi.org/10.1002/agj2.20198
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Pudzianowska, M., Mock, T. J., Martin, P. M., Lukaszewski, A. J., & Baird, J. H. 2020. Kikuyugrass germplasm collections in the United States and Australia show low levels of genetic diversity as revealed by DArTseq genotyping. Crop Science, 60(5), 27682781. https://doi.org/10.1002/csc2.20231
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Xiang, M., Schiavon, M., Orlinski, P., Forconi, A., Baird, J.H. 2020.Identification of Wetting Agents for Water Conservation on Deficit-Irrigated Hybrid Bermudagrass Fairways. Agronomy Journal. p.1-27. https://doi.org/10.1002/agj2.20450
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Petelewicz, P., Orli?ski, P.M., Schiavon, M., Mundo-Ocampo, M., Becker, J.O., Baird, J.H. 2020. Fluopyram Controls Shoot-Galling Caused by Pacific Shoot-Gall Nematode and Improves Turf Quality in Annual Bluegrass Putting Greens. HortTechnology. 30:709-718. https://doi.org/10.21273/HORTTECH04680-20
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Pudzianowska, M., Baird, J.H. 2020. Genetic diversity and species-specific DNA markers of Cynodon Rich. Crop Science. p.1-32. https://doi.org/10.1002/csc2.20369
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Orli?ski, P.M., Petelewicz, P., Schiavon, M., Mundo-Ocampo, M., Becker, J.O., Baird, J.H. 2020. Pacific Shoot-Gall Nematode Control in Annual Bluegrass Putting Greens Using a New Formulation of Abamectin. International Turfgrass Society Research Journal. p.1-20.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Schiavon, M., Petelewicz, P., Orli?ski, P.M., Baird, J.H. 2020. Effects of Fungicides on Creeping Bentgrass Health and Rooting Characteristics Under Abiotic Stress. International Turfgrass Society Research Journal. p.1-22.

Progress 05/17/19 to 09/30/19

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?A total of 5 papers summarizing this research were presented at the 2019 ASA/CSSA/SSSA meetings in San Antonio. How have the results been disseminated to communities of interest?Results were presented at industry meetings in California and abroad, as well as at the 2019 UCR Turfgrass & Landscape Research Field Day in Riverside. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Goal 1. Planted ca. 860 bermudagrass hybrids generated by open pollination and controlled crosses of selected collection accessions. Continued crossing of UCR bermudagrass accessions, with emphasis on genotypes possessing desirable winter color retention, early spring green-up, and drought tolerance. Continued evaluation ca. 1,000 bermudagrass and zoysiagrass accessions in replicate plots from University of Florida, Oklahoma State University, Texas A&M, and UCR for winter color retention. Planted 12 bermudagrass hybrids selected for roughs or lawns at The Preserve at Santa Lucia, Carmel and West Coast Turf in Coachella Valley. Selected 4 best performing bermudagrass hybrids out of 12 evaluated for 2 years. Planted large areas of 4 selected bermudagrass hybrids on fairways at Napa Golf Course and Almaden Country Club, San Jose to evaluate under traffic in comparison to Bandera, Celebration, Latitude 36, Santa Ana, Tifway II, TifTuf and Tahoma 31. Planted 16 zoysiagrass experimental hybrids and 4 cultivars from Texas A&M at Napa Golf Course and Meadow Club, Fairfax in Northern California. Goal 2. Utilized DArT to help California sod producer determine basis for bermudagrass off-types in their fields. Goals 3 and 4. Evaluated 17 products under salinity conditions. Three treatments containing phosphite produced exceptional turf quality under stress caused by saline irrigation and causal organism of Rapid Blight disease. Goals 5 and 6. Evaluated 11 wetting agent treeatments under deficit irrigation. All treatments improved turf quality compared to the untreated control. These results identified products that are more cost effective for water conservation on large areas such as golf course fairways. Goals 7 and 8. Research continued in San Francisco while new studies were initiated in Truckee, Sacramento, Los Angeles, and Bend, OR to compare rates and timings of these herbicides.Research results have pointed toward root architecture (depth and density) as being among the most important factors contributing to turf tolerance to methiozolin herbicide.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: UCR Turfgrass & Landscape Research Field Day Booklet. 2019. 67 pp.