Annual ryegrass is one of the most widely used cool-season forages in the Southeast. Its versatility, quick establishment, and grazing potential make it a cornerstone of fall forage systems. But not all ryegrasses perform the same. The choice between diploid and tetraploid varieties — and their specific traits like cold tolerance, disease resistance, and regrowth — determines how well pastures hold up through winter and into spring.
This guide breaks down ryegrass options to help you select the right fit for your farm this fall.
Understanding Diploid vs. Tetraploid Ryegrass
-
Diploids (2 sets of chromosomes):
-
A plant that contains two complete sets of chromosomes, one from each parent.
-
In terms of forages, diploids tend to have:
-
A slightly lower crown
-
Narrower leaf blades
-
More tillers
-
Smaller cells and cell walls, which means lower overall moisture content
-
-
Diploid ryegrasses, in general but not always, tend to be more cold-tolerant than tetraploids.
-
They also tend to be more tolerant of close grazing because they have a lower crown and more tillers.
-
-
Tetraploids (4 sets of chromosomes):
-
Because of twice as many chromosomes, they tend to have wider leaf blades. They also larger cell walls which hold more water and slightly more water soluble sugars.
-
These traits can lead to slightly improved palatability but can also lead to more recovery time after close grazing.
-
Tetraploids, in general, have less cold tolerance because they have more water in their cell walls that can burst during freezing.
-
For the most part, tetraploids are more suited to the deep south. However, the more cold tolerant varieties can be used in the mid-south where they won't be called on for production until springtime.
Leading Diploid Ryegrass Varieties
-
Grits – Popular in the Deep South. Fastest to emerge each year, excellent regrowth, and handles poor fertility. Less cold-tolerant, not recommended above I-20 unless used as a rescue crop.
-
Lonestar – Extremely cold tolerant with early production. Adjusts maturity with latitude (earlier in the South, later further north). Blends well with small grains or tetraploids.
-
Fria – Among the most cold-tolerant annual ryegrasses available. Strong choice in Tennessee and North Alabama, but increasingly used further south.
-
Centurion – Later maturity like Marshall but with much better disease resistance. A consistent top performer in GreenPoint Ag trials. Pairs well with diploids (Fria, Lonestar) or tetraploids (Tetrastar, Trinova).
-
Cold Green – Similar to Fria, bred for cold tolerance but slightly later maturing. In 2025 Tennessee trials, it stood out as the only variety not severely lodged after a storm.
Leading Tetraploid Ryegrass Varieties
-
Tetrastar – Consistently near the top for both yield and forage quality. A dependable performer across locations.
-
Trinova – More erect growth and less lodging risk than many tetraploids. Added stem structure gives it better durability under grazing.
-
Rival – One of the most cold-tolerant tetraploids. Proven for hay and baleage in Georgia. High yield potential; winner of 2025 GreenPoint on-farm trial for dry matter yield.
-
Attain – Strong in coastal and central Alabama. Performs well where fertility is high and cold pressure is lower.
-
More – The latest-maturing variety offered. Turf-like growth habit with heavy tillering. Provides extended season grazing.
-
Marshall – Historically well known, but highly susceptible to crown rust. Still used as a benchmark variety in university trials.
Diploid + Tetraploid Blends
-
Cold Green x Rival Blend – Combines early, cold-hardy establishment (Cold Green diploid) with later, high-yield performance (Rival tetraploid). Provides season-long balance and resilience.
Matching Varieties to Farm Goals
-
Early Grazing: Grits (Deep South), Lonestar, or Florida 401 rye when paired with ryegrass.
-
Cold-Prone Areas (TN, KY, North AL): Fria, Centurion, Rival or Cold Green.
-
Quality + Palatability: Tetrastar, Trinova, Rival.
-
Hay/Baleage: Rival and Trinova stand out.
This fall, choosing the right ryegrass is about matching variety traits to your region and forage goals. With the right mix of vigor, cold tolerance, and maturity, you can set up your pastures for success from fall through spring. Contact us for tailored recommendations for your farm.
