Traditional plant breeding can create low-emission pasture

Friday 28.02.2020 , News

General Manager of Germinal New Zealand Sarah Gard argues that traditional plant selection and breeding is a viable option for creating low-emission pasture.

With the Government signalling a much stronger commitment to reducing New Zealand’s greenhouse gas emissions, the focus has gone squarely on one of this country’s biggest agricultural emissions – methane gas produced by grazing animals, particularly dairy cows.

Methane production is a natural by-product of digestion, especially in ruminants such as cattle, sheep and deer. Dairy cows, because of their size and the types of pasture they eat, can produce a lot of it.

Research has focused on a number of options to reduce the amount of methane cows produce. These include: improving the quality of pasture feed generally, which in itself would reduce methane production; ‘inoculation’ of cows with substances that inhibit methane production; and the possibility of creating grass that produces less methane as it is digested. The latter is commonly referred to as ‘low emission grass’ and a lot of focus has been on the very real possibilities of creating such a grass through genetic modification.

Creating low-emission grass

There is, however, another option to create low-emission grass. It is an option that has been in use for many hundreds of years – conventional plant breeding.

Plant varieties with desirable traits are carefully selected and cross-bred to embed and strengthen desired qualities such as higher yields, disease resistance, colour and size, and environmental tolerance. Most of the common fruit and vegetables humans consume today are the result of generations of selective breeding.

New Zealand has unique climatic and pest conditions so, when it comes to pasture plants, new forages must be bred locally to guarantee performance.

Recently, global developments in gene editing and genetic modification (two different techniques) have attracted a lot of attention. The last review undertaken by the Royal Commission on Genetic Modification in 2001 concluded “it would be unwise to turn our back on the potential advantages on offer, but we should proceed carefully, minimising and managing risks”. There is no doubt New Zealand will need to keep up with international gene editing and genetic modification technologies if we are to have them as a viable option.

However, I believe we must not lose sight of the huge potential for low-emission grass created through conventional plant breeding, where neither genetic modification nor gene editing is required.

No genetic modification needed

Low emission grasses that are not genetically modified are already improving animal performance and leading to significant environmental benefits. For example, New Zealand data shows methane emissions reduced by 9% when sheep changed from grazing standard ryegrass to Germinal’s conventionally-bred high sugar grass.

High sugar grass means more energy is available for the microbes in the rumen, and this is significant in the way it helps ruminant livestock improve their conversion of grass protein into meat and milk. Improved digestive efficiency produces less methane, and another environmental advantage of reducing nitrogen excretion.

Conventionally-bred, low emission grass that improves livestock performance while reducing their carbon footprint offers New Zealand farmers a real win-win. It’s a modern solution to today’s farming challenges that comes out of the experience of many generations of conventional plant breeding; and it requires no notable change of system.

There is also potential for conventional plant breeding programmes to be used alongside gene editing. A relevant example for ryegrass breeders is using gene editing technologies to improve endophytes, which can then be introduced to conventionally bred varieties and produced naturally. An endophyte is a fungus found in ryegrass pastures that provides pest protection, therefore increasing plant persistence.

The success of New Zealand agriculture relies heavily on pastoral grazing. The international plant breeding landscape is changing rapidly, and the use of gene editing in New Zealand’s primary industries is an important discussion to be had, but it is a discussion still fraught with dissent on such issues as risk, ethics and customer acceptance.

Throughout this process, the success of conventional plant breeding programmes should not be discounted.

Sarah Gard is the General Manager of Germinal New Zealand. She has a Bachelor of Agricultural Science (first class honours) and oversees the company’s plot trials and new varieties breeding programme in New Zealand. She farms with her husband Will at Swannanoa, in the Waimakariri District near Christchurch, where Will is the farm manager of a 384ha, 1030 cow dairy farm.