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 Moy to the latest maturing Veritas.
- 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 first 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 three to four week spread in most years which is maintained 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.
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 2006-07:
Eight hybrid varieties have had their recommended status changed. Drumlin, Hymer, Pirol and Foyle have moved up to the fully recommended category and Twyblade has moved down from ‘Bold’ to ‘Plain Type’. Gazella, previously ‘Outclassed’ and has now been removed as has AberLinnet and Brutus as seed production has ended.
- 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.
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.
- Recommended changes for 2006-07:
Two Italian varieties have had their recommended status changed. AberEpic has moved up to fully recommended from ‘Provisional’ and AberComo has been removed as seed production has ended.
- 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 as indicated below.
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 2006-07:
Three Timothy varieties have had their recommended status changed. Dolina has moved up to ‘Bold Type’, Presto has moved up from ‘Provisional’ to fully recommended and Goliath has been removed as there is no longer any seed production of the variety.
- Seasonal yields of Timothy:
There is 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.
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 2006-07:
Two clover varieties have had their recommended status changed. Aber.S184 and Kent Wild White have been downgraded to the ‘Outclassed’ category.
- 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 Fennema (perennial ryegrass) at 250 kg/ha.
