Success story: 5 March 08
Endophyte research aids agricultural industry

Foundation? investment over more than two decades into research and development of rye grass endophytes is paying significant dividends for New Zealand’s agricultural industry.

An endophyte is a fungus that occurs naturally in many grass species, including ryegrass. It helps plants resist pests but can be toxic to animals, causing potentially fatal ryegrass staggers and heat stress.

A multi disciplinary approach from AgResearch scientists, based on years of collecting wild endophytes from around the world and selecting those with beneficial characteristics, has produced new endophyte strains, including AR1 and AR37.

The science represents a quantum leap forward in eliminating toxicity to animals and makes the AgResearch team world leaders in the development of safe ryegrass endophytes.

AR37 cultivars also provide greater protection against a broader range of pests, such as Argentine stem weevil, mealy bug, root aphid, black beetle and porina.

However this protection and the productivity it confers are at the expense of a trade-off in effects on livestock. AR37 is very much healthier for livestock than the toxic strains common in old New Zealand pastures, but not as totally toxin-free as AR1. All cultivars undergo rigorous animal safety testing before they are licensed to market.

Extensive trials show that ryegrass with AR37 endophyte gives an average increase in ryegrass production of 12 per cent over ryegrass with standard endophytes.

Research results from the earlier AR1 beneficial endophyte strain showed it provided sheep farmers with additional returns of around $200 to $250 per hectare. AgResearch scientist Lester Fletcher believes the higher herbage production from ryegrass with AR37 will translate into higher carrying capacity, leading to even greater returns per hectare.