Diploid, tetraploid, perennial, high sugar – there’s a host of terms and labels surrounding New Zealand’s ryegrasses. While farmers are aware of these terms, it’s worth revisiting them to better understand the options available in New Zealand with the availability of Germinal’s superior-performing Aber High Sugar Grass.
Diploids vs tetraploids
When it comes to diploid versus tetraploid perennial ryegrasses, the answer is easy – it’s a numbers game: diploids have two sets of chromosomes per cell, while tetraploids have four.
“This means tetraploids are more palatable for stock, which improves intake and increases animal production,” says Germinal New Zealand Senior Research Agronomist Kate Peddie.
“Tetraploid cells also contain readily available nutrients, including sugars and starches necessary for more efficient rumen function – meaning grazing animals get more food value from each bite.”
New Zealand’s ryegrass pastures have been dominated by diploid varieties, with commercial varieties of perennial tetraploid ryegrass only becoming available in the 1980s. Since then, farmers have increasingly used a pasture mix containing both diploid and tetraploid varieties, utilising the advantages of both.
Kate says diploid plants tend to have more tillers per plant and, due to the lower water content per cell, a higher dry matter per kilogram of feed. However, the more palatable tetraploids mean that stock eat more grass.
High Sugar Grass
Significant plant science research has occurred since the 1980s with breeders exploring the advantages and disadvantages of diploid versus tetraploid and seeking to breed varieties that have better qualities of each. That’s where Germinal’s Aber High Sugar Grass comes into its own.
Exclusive to Germinal, Aber High Sugar Grass comprise a range of perennial ryegrass varieties bred to produce more water-soluble carbohydrates (WSC) or sugar energy – delivering up to 17% more WSC than a conventional diploid ryegrass.
“The problem with grazing animals is that they are highly inefficient when it comes to converting plant protein into milk or meat,” says Kate. “Only about 25% of plant protein is turned into animal protein, with the rest excreted into the environment as methane, nitrous oxide or ammonia.
“The high sugar content of high sugar grass creates a better balance of energy and protein in the rumen, allowing the microbes responsible for the breakdown of forage to operate more efficiently.
“As a result, more grass protein is converted to meat and milk – with less protein wasted – and ammonia and methane emissions are reduced. That’s exciting news for New Zealand farmers seeking to improve stock performance while complying with new environmental standards.”
Aber HSG for New Zealand farmers
Germinal's high sugar ryegrasses have been bred to contain a higher level of water-soluble carbohydrates, or sugars, than traditional perennial ryegrass. There are three varieties available to New Zealand farmers from Germinal New Zealand.
AberGain was the first tetraploid high sugar grass released in New Zealand. Tetraploid perennial ryegrasses provide higher utilisation and increased production per hectare compared with diploid perennial ryegrass, due to increased palatability and greater animal preference.
AberGain provides all these benefits, plus it is densely tillered for improved recovery from severe grazing events, offering farmers real potential to increase their animal production.
AberGreen is the first perennial ryegrass to offer the closest to optimum energy-protein ratio. This creates a better balance of energy and protein in the rumen, allowing the microbes responsible for the breakdown of forage to operate more efficiently, so more protein is converted to milk and meat and less is excreted into the environment.
AberGreen offers vigorous ground cover, excellent digestibility under grazing and silage management, and is bred for enduring persistence and superior late spring yields. It’s also 5.5% higher in digestibility compared with standard ryegrass.
AberMagic is a new generation High Sugar Grass that offers even higher sugar levels with excellent quality under grazing and silage management.
It’s a deep-rooting ryegrass with very dense tillers, making it a robust plant for all farm types. The increased ground cover makes it hardy under pugging and the greater root mass allows it to tolerate reduced soil moisture. AberMagic is also 5% higher in digestibility when compared to standard ryegrass.
Adding in clover
Adding clover to pasture seed mixes can also provide a natural nitrogen fixer, reducing the need for synthetic nitrogen fertilisers and, therefore, reducing farmers’ costs and environmental impact.
Check out Germinal New Zealand’s clover varieties here.