Recommended Perennial Ryegrass Varieties
Perennial Ryegrass Maturity Groups
Perennial
ryegrass varieties are grouped into three heading date classes,mainly for ease of management of trials.
When comparing varieties for farming use, they are best regarded as existing in a continuum that currently
extends from the earliest maturing variety, Donard, to the latest maturing Twytop.
It
is vital to realise that the latest maturing varieties in one group may be of a similar type to the
earliest maturing in the next. For example, in terms of maturity, there is a greater difference between
the intermediate varieties Spelga and AberMagic (9 days), than between AberMagic and the ‘late’ variety
Denver (3 days). Consequently, the perennial ryegrass varieties have been listed in one table to assist
growers to compare across the maturity groups and avoid excluding varieties simply because of their
classifi cation label.
Throughout this continuum, however, there is an expected
progression of higher spring yields associated with earlier heading dates and the development of secondary
mid-season heading being lower the later the maturity. Similarly, the rate of stem development and yield
accumulation prior to the fi rst silage cut should show a progressive delay from the earliest to the
latest maturing variety. Varieties that outperform these conventions, based on their position in the
maturity continuum, can be regarded as elite performers.
Recommendation
changes for 2011/12
Two early varieties had their
recommended list status changed. Genesis and Moyola were upgraded from ‘Plain Type’ to ‘Bold Type’.
Nine intermediate varieties had their recommended list
status changed. In the diploids, one new provisional recommendation, AberGreen, was added to the list.
Boyne and Gerrison were moved up from provisional to ‘Plain Type’ and AberMagic was moved up to ‘Bold
Type’ whereas Cashel was downgraded to ‘outclassed’. In the tetraploids, AberGlyn, a ‘Bold Type’ variety
was given ‘S’ status and a new provisional variety, Seagoe, was added to the list. Garibaldi and Greengold,
having been outlassed, were removed from the list.
Seven late
varieties had their recommended status changed. Two diploid varieties, Mateon 1 and Drumbo were
upgraded from ‘Plain Type’ to ‘Bold Type’ and one new provisional recommendation, Glenveagh was added.
In the tetraploids, AberBite was upgraded to ‘Bold Type’ status, whereas Millennium was downgraded from
‘Bold Type’ to ‘Plain Type’ status. Diasa was added as a new provisional and Loporello was downgraded
to outclassed.
Diploid Perennial Ryegrass Varieties
These
varieties comprise the majority of the seed sold in Northern Ireland either as ‘straights’ or in mixtures.
They are long lived and form swards of good density, giving them a high damage resistance. They are
well suited to a wide range of enterprises as the diverse selection of varieties is capable of producing
high silage yields or maintaining high grazing outputs throughout the growing season.
Seasonal
Yields of Diploid Perennial Ryegrass
The seasonal yield distribution
of these varieties shows a progression of increasing early season yields from the latest to the earliest
varieties and increasing summer production with later heading. The varieties all undergo the same cycle
of simulated rotational grazing cuts with ‘Spring’ growth up to the end of April, ’Early Summer’ growth
to the end of July, ‘Late Summer’ to the end of September and the ‘Autumn’ period ending in early November.
The fi rst silage cuts are normally completed by mid-May for the early, the end of May for the intermediate
and during early June for the late varieties. This gives a 3 to 4 week spread in most years, which is
retained to the end of the third cut, resulting in different periods of ‘Aftermath’.
Tetraploid
Perennial Ryegrass Varieties
These varieties tend to have high sugar
contents and a tall upright growth habit that promotes high intakes when grazed. They also contain some
of the highest yielding perennial ryegrass varieties. Although equally long lived, they are more open
growing than the diploid varieties with which they are normally mixed in order to increase sward density
and damage resistance.
Seasonal Yields of Tetraploid
Perennial Ryegrass
The yielding pattern of these varieties shows
the same progression of seasonal yields as the diploid varieties. The same cycle of simulated rotational
grazing cuts is used, with ‘Spring’ growth up to the end of April, ‘Early Summer’ growth to the end
of July, ‘Late Summer’ to the end of September and the ‘Autumn’ period ending in early November. The
same silage system is also used to give a ‘1ST cut’ by mid-May for the early, by the end of May for
the intermediate and during early June for the late varieties. This three to four week spread in most
years means that the ‘Aftermath Grazing’ begins in mid-August for the early, late August for the intermediate
and early September for the late varieties.
Recommended
Hybrid
Ryegrass Varieties
Hybrid Ryegrass Types
Hybrid ryegrass
varieties are a cross between perennial and Italian ryegrass and some strongly express the perennial
or Italian parentage. ‘Italian-like’ hybrids have the highest yields but lowest sward densities, whereas
‘perennial-like’ hybrids are expected to live longer, potentially up to five years if carefully managed.
Varieties achieving both high yield and density can be regarded as elite performers.
Recommendation
changes for 2011/12
One new provisional recommendation,
Scapino (HT) has been added to the list this year.
Seasonal
Yields of Hybrid Ryegrass
The seasonal yield distribution of these varieties
is strongly influenced by the differing seasonal
growth characteristics of their Italian and perennial parentage. The very high early spring performance
of some varieties by the end of March is an Italian ryegrass derived feature. All these varieties continue
growing strongly after the two silage cuts are completed by mid-July, to provide substantial aftermath
outputs.Recommended Italian
Ryegrass Varieties
Italian Ryegrass Performance
Italian
ryegrass is the highest yielding of all recommended grasses but is short lived and best utilized for
silage. Higher density varieties may be more damage resistant but none form dense soles. Second year
yields are shown as a percentage of the first year control yield, to highlight the difference in annual
outputs.
Recommendation changes for 2011/12
Six
Italian ryegrass varieties had their recommended list status changed this year. Three tetraploid
varieties: Dorike, Hunter and Barmultra II have been moved up from provisionally recommended to plain
type this year: Ligrande has moved down from plain and is now outclassed. AberEpic and AberMario have
been removed from the list because commercialisation and seed supply for Northern Ireland have ceased.
Seasonal Yields of Italian Ryegrass
The
seasonal yield distribution of these varieties comprises a very high output by the end of March (‘Spring
Grazing’) followed by two excellent yielding silage cuts, completed by mid-July, to leave the option
of further cuts or a very substantial aftermath grazing performance.
Recommended
Timothy
Varieties
Timothy Maturity Types
The overall
yield
potential of Timothy is less than perennial ryegrass but can be more productive in cold Springs or can
maintain density and growth on heavy, less fertile soils. ‘EARLY’ maturing varieties are generally erect
and highly productive in Spring and ‘LATE’ maturing varieties are more dense growing pasture-types.
Recommendation
changes for 2011/12
All varieties remained with the same recommended
list status and Narnia was confirmed as an intermediate maturing variety.
Seasonal
Yields of Timothy
There is normally a sharp distinction between the early
season performance of early Timothy varieties and the summer production of the late varieties, particularly
under a silage management. The grazing and silage systems used on all these varieties were as used for
the intermediate perennial ryegrasses.
Recommended
White
Clover Varieties
White Clover Leaf Classification
As
variety leaf size increases yield should rise and grazing persistence decrease. Large leaved varieties
tend to be the most tolerant of tall grass stands but least tolerant of close defoliation. Varieties
achieving yield and persistency above the expected leaf size trend are elite performers.
Recommendation
changes for 2011/12
One White Clover variety,
Triffid
has been reinstated as it is commercially available again. All other varieties remained in either the
highest ‘Bold Type’ or intermediary ‘Plain Type’ categories.
Production
and Sward Content of White Clover
Total
yield (grass + clover) of grass/clover swards depend on the clover contributing nitrogen to enhance
grass growth, but the nutritional value of the sward is enhanced by higher clover contents. All clovers
were grown with Premium (perennial ryegrass) at 250 kg/ha N.
