Stability and purity of selected ryegrass Epichloë endophytes in New Zealand dairy pastures

Abstract

BackgroundPerennial ryegrass (Lolium perenne) in New Zealand pastures is typically infected with the mutualist Epichloë fungal endophyte. This endophyte assists the plant in resisting biotic and abiotic stresses, but the standard strain of endophyte is toxic to livestock. Elite ryegrasses with selected endophytes have been developed to provide protective properties to the grass plant and lessen or eliminate the negative impacts on livestock.MethodsUsing immunology and molecular techniques, the presence of endophyte infection and endophyte strain in ryegrass tillers was determined for 24 dairy pastures sampled for up to 7 years in regions of the North and South Islands.ResultsIn general, infection levels were high and showed small increases over time. Some pastures failed to reach 70% infection. The sown, selected endophytes were the dominant endophyte strains present and these were stable over time. Standard endophyte was the primary nonsown endophyte, and while generally low and so of little importance, it increased over time and for some pastures, this would have been detrimental to livestock. Pasture establishment technique influenced the level of contamination.ConclusionsResults reinforce the importance of following best practice procedures in the seed industry and on‐farm. Researchers should monitor trials for contaminating nonsown standard endophyte.

Effects of heading date and Epichloë endophyte on persistence of diploid perennial ryegrass (Lolium perenne). 2. Endophyte strain and interactions with heading date

“…Contamination of pastures with non-sown toxic endophytes such as SE is of concern if the animal health and productivity advantages of selected endophytes are to be realised and maintained over time (Hume and Barker 2005;Hume et al 2024). SE was the major contaminating endophyte in the nea2/6-infected and AR37-infected plots, and although low at just 4%, this level of contamination increased over the experimental period (from 2.5% to 7.6%), similar to that reported for commercial dairy farms in the upper North Island (Hume et al 2024).…”

Introduction to the XXV International Grassland Congress virtual special issue

“…Tucker et al (2024) reviewed management for utilizing alfalfa as part of beef, dairy, and finishing systems, as well as identifying educational programming efforts and on-farm demonstrations to promote alfalfa as a component of the livestock diet, integration into grassbased systems, crop rotations, and wildlife use. Hume et al (2024) described the stability of introduced Epichloë endophytes of ryegrass over a 7-year period in New Zealand dairy pastures. Some postcongress news to note is that a website containing congress proceedings has been developed.…”