Summary

Materials used for seed pelleting have been found to be incompatible with rhizobia and potentially the major cause of poor microbiological quality of preinoculated seed. This project aims to survey products available for seed coating and evaluate their potential for improving rhizobial survival.
Commercially available polymer adhesives, colourants, agrochemicals (insecticides, fungicides) and micronutrients used in preinoculated pelleted seed will be collected throughout Australia. It is envisaged that this will be done with the cooperation of the seed pelleting companies, the inoculant manufacturing industries and manufacturers who produce the various products.
At the commencement of each year of the project, companies will be invited to supply materials that they use or which have a potential to be used in seed pelleting production. These products will be tested for their compatibility with several rhizobial strains (used to inoculate pastures) both in vitro and on seeds.
Once the compatibility tests with rhizobia have been completed, those products which are rated as compatible will progress to the next stage to determine their suitability when combined with other ingredients. A suitable dilution application rate for products with poor compatibility will be determined. If a satisfactory application rate can be established, these products will also be assessed in combination with other ingredients. Products which are highly deleterious to rhizobia will be classified as such and given a non-compatibility rating.
At the completion of the project, a risk analysis will be carried out using the results of the compatibility assessments. Materials will be rated according to their suitability for use in the seed pelleting process containing rhizobia.

Program

Pasture Seeds

Research Organisation

The Crown in right of the State of NSW acting through the Department of Primary Industries

Objective Summary

1. To survey the available commercial polymers, colourants and other materials used in legume pasture seed inoculation and rate their compatibility with rhizobia.
2. To assess commercially available polymers for their ability to protect rhizobia from the adverse effects of desiccation and hence improve survival of rhizobia on pre-inoculated legume pasture seed.
3. To publish the results and conduct a workshop to provide commercial seed pelleters with a decision tool for the selection of suitable materials for seed preinoculation
4. Establishment of a quality control system for the on-going monitoring of commercial preinoculated seed products.