Cooperate in the 2024 Perennial Ryegrass Trial

Use the form shared here to submit your RFI before September 15th 5pm Pacific to be considered. The 2024 Perennial Ryegrass is planned to run at six (6) locations across North America. The trial will be packaged and distributed to cooperators in August of 2024 for timely establishment. Trialing is anticipated to run three (3) years across locations. Trialing is governed by the TWCA cooperator manual. TWCA supplies cooperators with standardized cameras. Cameras are returned to TWCA annually for callibration and inspection. Cooperators receive a fresh set of light bulbs for the lightbox annually ensuring standard photography and standard lighting. 
Cooperators are expected to submit data via Teams using TWCA supplied formats. This aides in rapid accurate analysis of data. Cooperators participate in two of three (2/3) annual cooperator calls. The first cooperator call of the year is held in February with calls recurring once every four (4) months for the duration of the trial

Why TWCA?

Dr. Melodee Fraser, Director of Research at Pure Seed Testing East and TWCA Cooperator perfectly sums up how TWCA validates drought tolerance in turfgrass cultivars through independent third-party peer review. 
Green up your conservation program with TWCA Qualified drought tolerant turfgrass.

Special thanks to Pure Seed, Pure Seed Testing and Dr Fraser for supporting TWCA.

​2022 Qualifications

Find Your TWCA!

TWCA is for everyone, but how can everyone find it? The TWCA Members map highlights TWCA members nearest you. Look for the seed and sod icons to find the vendor you need.  Be forewarned though, sod vendors ALSO carry seed! So, if you are looking for seed, don't be afraid to reach out to sod vendors too!

Turfgrass Water Conservation Alliance (TWCA) is a 501c3 non-profit dedicated to water conservation and committed to preserving the ecological benefits of turfgrass in the managed environment.  TWCA relies on third party peer review of objective data to qualify the most drought tolerant turf available today. 
Using strong research TWCA advocates for the responsible use of drought tolerant turf in landscapes to preserve the livability and viability of communities around the world.
​
​Technology
TWCA and its cooperators pioneered the use of Digital Image Analysis (DIA) to collect and evaluate stress related data in turfgrass.  This includes NexGen Turf Research and University of Arkansas developing the  lightbox technology widely considered industry standard and developing the Turf Analyzer tool.
These revolutionary technologies, coupled with the use of Rainout Shelters (ROS)s allow effective and accurate evaluation of multi-year multi-site trialing.

TWCA Cooperator demonstrates DIA data collection with a lightbox at NexGen.

Trialing Types
During the single species  evaluation process; TWCA utilizes both Drought and Low Maintenance trialing.  Drought trialing gives an accurate accounting of cultivar performance under drought stress.  Low Maintenance trialing, on the other hand, looks at turf performance under a decreased inputs regime.
TWCA evaluates two types of drought stress; chronic and acute.  Chronic stress is a low water scenario where the turf is brought to uniform green before being watered at a decreased evapotranspiration (ET)  rate.  Chronic stress is excellent at simulating water requirements in a decreased water scenario similar to a daily or weekly watering restriction.  However, it is fairly labor intensive.  TWCA research cooperators have shown through repeated trialing, a high correlation between drought tolerance performance in chronic and acute conditions.  For these reasons, this is a less common approach in the program.  Acute stress, on the other hand, is a zero water evaluation, where, established turf is brought to uniform green and field capacity before the water is entirely shut off.  This is a prolonged drought, no water scenario and provides a smooth uniform performance curve for evaluation.  Drought trialing is all governed by the TWCA's Turfgrass Water Conservation protocol.
Low Maintenance trialing presents a unique evaluation challenge.  Unlike TWCA drought trialing with one variability (drought) low maintenance functions with a broad spectrum of variables.  The trialing regime bans herbicides and pesticides completely and restricts fertility to between 1 and three pounds per one thousand square feet.   On top of all this the low maintenance regime also imposes acute drought stress.  A key requirement for any cultivars coming out of the low maintenance regime is qualification through the TWCA Drought process.
Regardless of the trialing regime imposed, all TWCA trials are standardized using the TWCA Cooperators Manual.  This manual lays out expectations for ROS construction, trialing conditions including, establishment, mowing height and fertility.  
​
​Qualification
TWCA Qualification relies on third party peer review of the objective data collected at all the locations.  The final qualifications are decided by the TWCA Research Review Committee.  Comprised of University Researchers with no vested interest in any cultivar being evaluated, the RRC meets to review and evaluate the data before making the final qualifications.  As qualified cultivars approach expiration, they must either requalify against a new, higher standard of drought tolerance or lose its qualified status.