They are adapting endophytes to wheat, in the belief this could improve the cereal crop’s resilience to pests and climatic pressures.
Grasslanz Technology’s chief executive John Caradus said early trial results looked promising for the long-term research project.
The focus on wheat followed 30 years of research identifying endophytes that benefit ryegrass plants, while not causing livestock health issues such as heat stress and grass staggers.
"We started thinking that maybe there was a way of taking some of the benefits of these epichloe endophytes that we have in our temperate grasses and perhaps putting them into cereals," he told growers at the Foundation for Arable Research’s CROPS 2022 field day at a research site near Ashburton.
Endophytes are a fungal symbiotic partner of grass that can protect it from insect pests and diseases and provide some resilience against drought.
The project to introduce a seed-transmissible endophytic fungus for commercial wheat has been supported by FAR for the past 12 years.
Mr Caradus said it was not possible to take the epichloe endophytes out of ryegrass and fescue and put them directly into cereals, as it was "too big a jump" across plant families.
"These fungal endophytes only live inside the plant and there is a genetic compatibility issue, so they will only generally live viably within the plant species from which they are taken. We looked at close relatives of cereals, as modern cereals don’t have these endophytes in them at all. They may have been bred out of them during the domestication of cereals — we don’t know."
Epichloe endophytes from wild relatives of cereals, mainly from Asia, were transmitted into a Chinese spring wheat and then backcrossed with commercial cultivars, producing plants with potentially reduced susceptibility in the field to both pests and diseases.
Early success with ryecorn, an out-crossing crop which has a lot of genetic variation, provided promise the same could be done with wheat.
"Wheats are inbred, so genetic variation in the host plant is quite narrow and so getting compatibility between it and the epichloe endophyte was quite a challenge. But we have managed to do it. That was the starting point. We still have quite a way to go in terms of plant performance by backcrossing with modern wheat cultivars."
The varieties include Firelight, Wakanui, Raffles and Viceroy.
Spring wheat grown in a small plot trial at Lincoln in 2021-22 showed that out of four treatments, the two with endophyte, both with and without pesticide, had only an 8% incidence of fusarium head blight. The treatment with no endophyte and no pesticide had a 68% incidence and the treatment with pesticide and no endophyte had a 31% incidence.
Leaf rust incidence was 62% per cent for the treatment with no endophyte and no pesticide. Treatments with either endophyte or pesticide were 2%, and with both, zero incidence of leaf rust was detected.
Mr Caradus said these results gave confidence that they needed to persist with the technology and continue investing as it would remove a "fair amount" of synthetic chemistry.
A lot of backcrossing is still required to get to the desired phenotype. At this stage the head size is small, the maturity within the plant is staggered, the seed weight is lower than modern cultivars and the seed has a shrivelled appearance.
"We can only do one backcross a year and there is a lot of other testing we need to do in terms of grain quality."
The programme was continually looking for new variations in endophytes and compatibility, with research focused on an endophyte named AR3002.
FAR research, development and extension general manager Andy Pitman said it was important to keep investing in projects which had the potential to transform the management of arable crops in the future. "AR3002 is showing early signs of promise and other endophyte strains with activity against aphids are also of interest."
