Endophyte seed tests
ALL Barenbrug ryegrasses containing endophyte are tested prior to sale and have a current test at time of sale. The type of endophyte contained in the seed is stated (e.g. NEA2).
Levels are given for the percentage of seed containing endophyte:
- NEA, NEA2, NEA4, NEA12, AR1 or AR37: 70%+ of seed contain stated endophyte
- LE or 'Low endophyte': less than 70% of seeds have endophyte
Endophyte level
A seed either has, or does not have endophyte, and this endophyte level for a line is given as a percentage e.g. a level of 80% means 80% of seeds contain endophyte and 20% do not.
For seed to be sold as containing an endophyte, a level of 70% or more is required. This may be NEA, NEA2, NEA4, NEA12, AR1, AR37 or another endophyte.
Seed classed as LE (Low endophyte) contains less than 70% of endophyte.
Endophyte levels in stored seed drop over time. To ensure high endophyte levels in our seed, Barenbrug uses controlled storage (see Storing Seed with Endophyte) with continual monitoring and re-testing of endophyte levels.
ELISA testing
The ELISA (Enzyme Linked Immuno Sorbant Assay) test ensures AR1 or AR37 are not contaminated by Standard endophyte.
The ELISA test determines the presence of lolitrem B in a seedline. Seed with Standard endophyte always contains lolitrem B. Seed with AR1 or AR37 doesn’t contain any lolitrem B.
The result of the ELISA test is reported as a grade that runs from 1 to 6.
Grades 1-5 are all acceptable for 1st Generation seed and mean less than 5% contamination. Grade 6 is not suitable for sale.
Testing seed for endophyte
Two tests are available.
1. Seed test:
This tests the seed directly. It is a quick test for presence of endophyte, but does not indicate whether the endophyte present is dead or alive. This is an overnight test typically done on newly-harvested seed up to 31 May.
2. Seedling grow out test:
This is used after 31 May, to ensure endophyte is alive. Seed is sown in our laboratory and the tiller of the resultant seedling is tested for endophyte after 3–6 weeks.