Grass seed is grown on farms and includes both turf or lawn grasses, ornamentals and grass seed grown for animal food. Grasses are often bred to include or accentuate certain traits. Warm-weather and cold-season grasses will differ in the traits that are sought for. For instance, a warm-weather grass will be bred to be drought tolerant and sunburn resistant. Many traits--dormancy, root depth, pest and disease resistances--can be instilled in a base grass crop to improve its composition.
What is a Cultivar?
Cultivars are a subset of a genus or species. They are also called a variety or release and are named by the breeder. The word cultivar comes from "cultivated variety." They are bred to perform a specific function or present a certain trait uniformly and consistently. Grass cultivars can be bred by anyone from scientists to seed production companies. They are diverse in their content, derivation, location of origin and species.
Who is Developing Cultivars?
In addition to individual development companies and seed producers, some government agencies are involved in grass cultivar research--predominantly to find replacements for native grasses. The National Resource Conservation Service's Plant Material Program looks at soil erosion problems and is part of grass development to manage areas where native grasses have died and erosion poses a threat. The USDA Agricultural Research Service is involved in grass development. A main function of the ARS is to collect plant material, store and maintain it for study and experimentation. Universities are also heavily involved in the research and creation of grass cultivars.
How Grass Seed is Grown
The location for grass seed production must be weed free and carefully cultivated. The soil should match the soil needs of the particular variety being grown. Adjacent fields should be free of noxious weeds and competing grasses to avoid establishment of an unwanted cultivar. Grass is sown with a layer of charcoal over it and is sprayed with a selective herbicide. Subsequent care includes watering, fertilizing with nitrogen and herbicide follow-up. Harvest begins in late June or early July with a swathing and windrowing. Windrowing is the process that separates the seed from the stems; swathing is just cutting down the seeded grass heads. Seed is cleaned and tested for purity.
The precise traits and use for the grass must first be defined. Will it be strictly for erosion control, planted in dry conditions or is it being cultivated for seed? The use and desired characteristics will govern the choices of parent plants for cross breeding. Selection of parent plants now uses genetic maps and codes to classify grass genes. Initial grass traits are available for breeders as start-up breeders lines for new varieties. The initial traits will come from a standard grass with habits that will be consistent in the new cultivar. Additional traits will be added on.
Process of Elimination
The parent plant with the initial desired traits is sown and grown. Individual plants are tested to see which are closest to the desired total traits. The closest plant is allowed to reproduce and the process repeats itself. The final cultivar can take many generations of grass seed crops to result in the enhanced seed. Cultivars can come from one plant from one area, several plants from one area, two plants from two different areas, etc. The undesirable traits will not be allowed to reproduce, encouraging the wanted traits. Crossbreeding is often a way to encourage traits, as is breeding of other cultivars.