In recent years there has been a significant move away from the
use of fine grass species such as browntop (Agrostis capillaris)
and fine fescue (Festuca rubra) in favour of turf-type
perennial ryegrass (Lolium perenne) for lawns and turf.
An important contributing factor to this move has been the dramatic
improvement in the quality of turf-type perennial ryegrass cultivars.
The rapid germination and quick establishment of perennial ryegrass,
even in cold conditions, make it easier and more reliable for homeowners
and contractors to establish. The newly sown lawn can often be used
within as little as four to six weeks.
Development of turf ryegrass
The first turf-type perennial ryegrass cultivar was bred 25 years
ago in the USA. At that time the New Zealand Government was concerned
that wholesale importation of dwarf turf cultivars could result
in the contamination of our own pasture seed industry so they introduced
an ‘acceptable cultivar list’. Only cultivars that were
tested and found to have merit were allowed into the country. After
careful assessment, it was realised that different cultivars could
be kept from cross pollinating if normal isolation practices were
followed. Now turf ryegrass seed is an important crop in New Zealand.
Interesting fact: The first use of a turf ryegrass
as a sports turf was in the late 1970s when the cultivar Manhattan
was imported from the USA and sown into the Basin Reserve cricket
Turf ryegrass did not gain immediate acceptance in New Zealand
because it could disappear completely in drier regions over a single
summer while in other areas it appeared to perform well.
In the 1980s New Zealand scientists, along with international collaborators,
found that surviving grasses contained a fungus that grew within
the plant. The fungus was consequently called an endophyte (pronounced
“end - oh – fight’) with the generic name of Neotyphodium
species. The association between the plant and fungus is synergistic,
as both organisms benefit. The endophyte makes the grasses resistant
to attack from insect pests, including Argentine stem weevil (Listronotus
bonariensis) and black beetle (Heteronychus arator),
improving the survival rates of the grasses. The resistance is due
to the release of a number of different alkaloids, including peramine,
that deter insect feeding. Plants infected with the endophyte do
not have disease symptoms. The fungus cannot be passed on to non-infected
turf. Instead, the turf can be given resistance to Argentine stem
weevil by over sowing endophyte-infected cultivars that replace
the susceptible cultivars over time.
Within a year of these discoveries, New Zealand turf grass breeders
in Canterbury found that almost all of the turf cultivars bred overseas
lacked endophyte. Nowadays, nearly all turf ryegrass cultures contain
Turf cultivars with high endophyte content have increased growth
and vigor, making them more tolerant to drought stress, summer weed
invasion, and other possible turf diseases. Endophyte affects more
than 40 invertebrate pests, mostly insects that feed on the lower
part of the tiller rather than root feeders such as grass grub (Costelytra
zealandica). Future research is likely to lead to endophyte strains
for turf that will provide resistance to an even wider range of
Buyers of perennial ryegrass seed are warned that much of the seed
sold to homeowners is of indifferent quality. Furthermore, seed
that is stored for 18 - 24 months under normal storage conditions
will lose its endophyte. Buyers must ensure they purchase good quality
seed by looking for the following:
1. is it a named turf cultivar that has been bred in the last 10
2. is it a cultivar with a high endophyte content?
3. is the seed less than 18-24 months old?
4. does the seed have a high germination rating, as determined by
a recent germination test?
5. is the seed pure, as indicated by a purity and germination certificate?