Program

New and Emerging Plant Industries

Research Organisation

Central Queensland University

Objective Summary

There are five main objectives and research avenues proposed for this project, the first four will be addressed under the current project proposal, the fifth, which will require additional resources and time, will be undertaken if RIRDC wish to make a variation to the project once FSANZ approval for the use of steviol glycosides as intense sweeteners is forthcoming:
1. a) Further development of technology based on near infrared spectroscopy (NIRs) scanning for rapid assay of glycoside content in plant material for use in variety selection work and for grading (on-farm or at processing mill receival) of dried stevia hay to determine quality grades as the basis for the payment to growers.
b) Further refinement of procedures for the reliable and accurate analysis of all glycosides using HPLC.
2. Undertaking of plant physiology and basic management practice studies to determine factors (including stresses) that influence or control flowering, glycoside accumulation, ratoon performance and total yield to optimise crop returns. These studies will include nutrient deficiency symptoms, irrigation and water tolerance and time of flowering and will identify criteria to use when selecting elite plants for seed production.
3. Further evaluation of weed control practices and herbicides to provide data for registration or permit-use of suitable chemicals to use with stevia.
4. Providing support for a limited number of farmers growing trial areas of stevia. This support will include provision of planting material and leaf analysis of plot samples.

Supplementary Objectives (following approval by FSANZ)
5. Commencement of a plant variety selection program to provide varieties better suited to the various regions of potential production and to undertake larger scale regional trials covering mechanical practices such as height of cuttings, harvest intervals, irrigation frequency and oxygation.