Make sure you select a true perennial ryegrass
15 February 2012
For the last couple of years farmer concerns being voiced regarding pasture persistence have increased markedly. This has been primarily focused on perennial ryegrass and a number of factors like pests, disease, endophyte and drought have been raised as contributing factors.
However the plant genetics has also got a big role to play and farmers need to pay close attention to the breeding history and make up of ryegrass cultivar genetics when considering and recommending what to plant. Seed Force’s Technical Director, Andrew Moorhouse explains.
“One of the major focuses for many ryegrass breeders in the last twenty years or so has been to develop new varieties which have strong establishment vigor and excellent cool season growth – both important on-farm considerations. The objective has been to extend the shoulders of the season so that pastures start producing earlier in spring and grow later into the autumn at the other end. To achieve this has meant the incorporation of Italian ryegrass genetics as part of the crossing program.
The species Perennial Ryegrass has the botanical name Lolium perenne. One of the important characteristics of Lolium perenne and the reason why it has been used so widely as a perennial pasture species for centuries worldwide, is its natural ability to continue producing high numbers of vegetative tillers over time. This means that as the older tillers mature and die, the pasture can still retain its density which maintains production and prevents the invasion of weed species.
Hybrids of Italian and Perennial Ryegrass will combine features of both parents but there is likely to be a trade-off so that as the proportion of Italian genetics is increased in the hybrid, there will increased cool season activity and establishment vigour but reduced production of vegetative tillers and therefore perenniality. Hybrids of Italian and Perennial Ryegrass are classified as Lolium x boucheanum.
If the longevity of your pasture is one of the main criteria when you select a new variety of Ryegrass to sow, here are a couple of checks that you need to make.
First of all you need to check that you are purchasing certified seed. This means that the seed falls under MAF’s national certification scheme and is guaranteed to be the variety stated on the bag. It also means that the seed will have guaranteed levels of purity (freedom from weeds). Certified seed usually has a blue label sown into the bag with all the details printed on it.
The second check is to make sure that if you want perennial ryegrass, that you are sowing Perennial Ryegrass and that it says Lolium perenne on the certification label.
“Another factor when considering your perennial ryegrass options is to evaluate the trial data. When reviewing perennial ryegrass trials note how many trials have been conducted, where they have been held and for how long. Ask yourself; are the trials published being carried out in your region under ‘real life’ grazing conditions or in an ‘ideal’ environment under irrigation in an area very different to yours? Many perennial ryegrass trials in New Zealand are run for only 3 years, therefore not measuring perenniality. Seed Force proudly has perennial ryegrass trials going into their 6th year”.
“A lot of discussion over the last decade or so has focused on the ability to improve pasture persistence through use of selected endophytes. Whilst having the correct endophyte for your situation is important, endophyte is not the silver bullet for persistency. When coupled with good genetics and breeding; endophyte plays an important role, but when a variety is sold on the grounds of its endophyte option only rather than its genetic benefits, then this is by no means the whole story regarding pasture persistence. You also need to confirm that the seed contains good levels of endophyte as this can decline over time.
Make sure you choose a genetically robust and persistent plant variety if pasture persistence is one of your key objectives”
If you want a true perennial ryegrass it should be defined as “Lolium perenne”- on the certification tag