Agronomists use of PGR - a survey

The objective of this research was to improve our understanding of perceptions and use of plant growth regulators (PGRs) in cereal production in Australia and to develop relevant research priorities. PGRs applied at the appropriate rate reduce plant height when applied at early stem elongation in cereals. Information was collated from a telephone survey of 142 Australian agronomists and a 12-person focus group on current PGR use. Lodging was identified by survey respondents as the main reason for recommending PGR use in grain crop management. The effect of PGRs on grain yield was reported to be inconsistent, which reflects the complex interactions between crop species and variety, the type, rate and timing of PGR application, plant phenology, and the impact of diverse environmental conditions.

Only 20% of agronomists surveyed indicated that they have recommended PGR use, because they were perceived as unsuited to specific growing regions and there is a lack of scientific evidence regarding their efficacy in crop production. Economic analysis showed that application of PGR with no yield response from 2.38 Mha would cost the industry around $70M. In contrast, relatively small 5 and 10% yield responses would result in a net profit of between $35M and $138M. Coordinated field experiments are required across a range of environments and treatment combinations to clarify the potential benefit of PGRs, and an analysis of the costs versus benefits of PGR use for a range of scenarios.