Search

Canada geese (Branta canadensis) and other herbivorous birds (e.g. paradise ducks, pukeko) can be a significant problem for both pastoral farmers and recreational turf managers in a number of locations in New Zealand. Canada geese were offered seeds and herbage of selected ryegrass combinations of (Lolium perenne) and endophyte (Neotyphodium lolii) to examine the effects of endophyte and the associated alkaloids on feeding behaviour. Forty geese were captured annually during the moult in January and contained in fenced areas by wing clipping. In both choice and no-choice feeding trials, geese consumed up to four times more endophyte-free than endophyteinfected ryegrass herbage. In a seed feeding trial, the geese did not discriminate on first exposure between the endophyte-free seed and that containing endophyte. However on Day 2 there was an 80% rejection of the seed containing endophyte compared to the endophyte-fr ee seed. A similar rejection of 80% was observed after a three month endophyte-free feeding period, suggesting the rejection was a long term learned response involving post-digestion feedback. Grass/endophyte associations may add to the armoury of bird control methodology as a tool to manage birds using habitat modification. Keywords: alkaloids, Canada geese, endophyte, herbage, post-digestion seed

Emergence of volunteer perennial ryegrass (Lolium perenne L.) from seed buried in soil may contribute to the ingress of ryegrass in newly sown pastures. To investigate this, ryegrass seed infected with fungal endophyte (Neotyphodium lolii) was buried in nylon bags under pasture at two depths and at two sites (Palmerston North, Lincoln) in early/mid-autumn 1998. Seed bags were removed from the soil at intervals over the course of one year to determine seed viability and presence of endophyte in seedlings. Viability of seed declined rapidly to be 10% 3 months after burial. Further decline in viability was less, so that 12 months after burial 4% of seeds were still viable. Endophyte viability also declined, from 58% infection of seedlings at the time of burial to 21% at 12 months. This was at a slower rate than the decline in seed viability and from what might have been predicted from seed storage experiments. Viability of seed buried at 10 cm was greater than that buried at 3 cm (e.g., means, 10% and 1% after 6 months, respectively). This has implications for cultivation practices before pasture establishment. Seed buried at Lincoln maintained higher viability than seed buried at Palmerston North (e.g., means, 6% and 4% after 6 months, respectively), which was associated with drier soil conditions at Lincoln. Survival of buried seed may therefore be of greater importance in summer-dry east coast regions, compared with moist west coast environments or in wet years. The significance of buried ryegrass seed will depend on the numbers involved, but after 12 months there were still viable seeds left in the soil and some of these were infected with endophyte. This is important for pastures sown with ryegrass that is free of endophyte or infected with a selected endophyte, and for slower establishing grass species such as tall fescue. Keywords: endophyte, endophyte survival, Lolium perenne, Neotyphodium lolii, perennial ryegrass, seed burial, seed survival

Seed Certification and Seed Testing Schemes provide the rules and guidelines to maintain both varietal genetic purity and physical purity during field production and seed processing. However the Seed Certification agencies are not involved in ensuring that the quality of the endophytic component of seed is maintained. The delivery of quality endophytic seed to end users therefore requires that the commercial seed entity that is producing and marketing a novel endophyte product develops and maintains strict production and quality assurance guidelines to ensure that the benefits of novel endophyte technology are realised. The paper uses the New Zealand (NZ) experience with AR1 endophyte in ryegrass and the USA experience with MaxQ® Jesup tall fescue to highlight the quality control steps required to deliver a quality product to end users. Keywords: novel endophyte, tall fescue, ryegrass, Neotyphodium, MaxQ, AR1, seed production

Fungal endophyte (Acremonium spp.) toxicity affects sheep and cattle grazing a number of forages, including ryegrasses (Lolium spp.) and tall fescue (Festuca nrundinacea). The endophyte in tall fescue is responsible for ill thrift, as indicated by low weight gains or weight loss(1) and decreased reproductive efficiency(2), and is associated with increased body temperatures. Extensive research has been undertaken in the USA to determine ways of reducing the impact of fescue toxicity on the beef industry(3), whilst New Zealand research is directed toward both ryegrass and fescue endophyte toxicity and its impact on sheep(4)(5) and cattle(6) production. Much of this work involves field evaluations of productive performance in animals fed toxic and non-toxic forage, so that it is important to be sure that treatment effects are due to the endophyte.

The effect of storage on viability of the Lolium endophyte fungus (Acremonium loliae Latch, Christensen and Samuels) in seed of perennial ryegrass was studied. Treatments included four initial seed moistures (13.8, 12.1, 10.0, and 8.6%); different storage bags (calico, polyethylene film (9, 35, or 70 μm thickness), and laminated aluminium foil-polyethylene); and four storage conditions (ambient 5–25°C, 5°C/70% RH; 0°C/30% RH; -15°C/90% RH). After 12 months of ambient temperature storage, seeds with final moisture contents > 11.3% had a rapid linear decline in endophyte viability from an initial 84% to < 15% at 13.0% seed moisture. Samples in 70 μm thick polyethylene and aluminium foil laminated packets had the highest endophyte viability (70–78%) at ambient temperatures. Seed stored at 5, 0, or -15°C had high endophyte viability with no effect of seed moisture. Seed germination was not affected by any treatments. Cool or low humidity environments ( < 60% RH) are required to maintain viability of ...