Scientists making 'steady progress' on genetically modified ryegrass

Scientists working on a genetically modified grass which could help reduce on-farm greenhouse gas emissions say results from field-trials are encouraging.

Work is being carried out by a team of scientists, led by AgResearch, into genetically modified High Metabolisable Energy (HME) ryegrass. 

Studies so far have shown the GE-modified ryegrass offers environmental and productivity benefits, including lower nitrogen excretion from animals, meaning less nitrate leaching and lower emissions of nitrous oxide.

AgResearch principal scientist Dr Greg Bryan recently returned from the United States where the Crown Research Institute is conducting field trials of the grass.

Science technicians begin harvesting the HME ryegrass grown in the United States.
Science technicians begin harvesting the HME ryegrass grown in the United States. Photo credit: Supplied

He said scientists had been conducting experiments to find out whether this new potentially environmentally sustainable grass will perform in the field in a similar way to how it performs in controlled environment studies. 

"The HME ryegrass has performed well in controlled growing conditions and I've recently returned from the United States where we are growing the plants in field trials in competition with one-another, just as they would in pasture and the plants are doing well," he said. 

"We're breeding the best novel traits into ryegrass cultivars that will best suit New Zealand growing conditions and we're also introducing genes into the plants that have simpler genetic patterns that will make future breeding programmes easier," said Dr Bryan.

Inside AgResearch’s new containment facilities in Palmerston North.
Inside AgResearch’s new containment facilities in Palmerston North. Photo credit: Supplied

"The ultimate goal of the United States phase of the research was to conduct realistic rather than simulated animal nutrition studies to evaluate whether the grass might have the potential environmental benefits, such as reduced methane emissions and reduced nitrogen excretion that our modelling suggests it will." 

While the results have been encouraging, Dr Bryan issued a note of caution. 

"This is complex long-term research and we are working on a species with challenging genetics. It takes several years to breed the HME trait into elite ryegrass varieties currently used by farmers, and very importantly, to test performance every step of the way." 

He said it was important to stress that the forecast environmental benefits associated with the grass need to be supported by rigorous research. 

"We have a good understanding of the potential benefits of the grass because of our institutional expertise in animal nutrition, from animal nutrition models, and from the biochemical analysis of the grasses in in vitro (test tube) studies. Eventually, we will need to seek regulatory approval for HME ryegrass to be grown here in New Zealand for livestock grazing trials."

Dr Bryan said the ryegrass would need to be tested in New Zealand conditions using New Zealand animals to ultimately confirm or refute the potential environmental and productivity benefits.