Ontario Grain Farmer March 2021

16 PLANT GROWTH REGULATORS (PGRs) have been used commercially in agricultural production dating back to the 1930s and 1940s. However, if one goes back even further, it is found that modifying plant growth by applying something to the plant has been done for centuries. For example, in the Middle East centuries ago, olive oil was placed on a fig just as it was beginning to ripen. By placing the oil on the fig, it helped contain a very small amount of ethylene gas that the fig produced, allowing the fig to ripen very quickly. Just to be clear, the ethylene gas is what helps the plant mature, not the olive oil; but by containing the gas, the farmers were able to encourage the plant to mature faster than normal. Plant growth regulators MODIFYING THE CROP Laura Ferrier PGRs are used in agriculture to modify a crop by changing the response to various factors that control plant development. Changing vegetative growth and reproductive growth and maturity are some of the common uses for PGRs in modern agriculture today. CURRENT USE Currently, there are a few PGRs available for use in Ontario. Many of them work by Agronomy