The effect of two plant growth regulators on the inhibition of precocious fruiting in pineapple Ananas Comosus L. (Merr.)

 The favourable summer and autumn climatic conditions of the Capricorn coast region in central Queensland can accelerate the growth rate of pineapple first ratoon suckers from a Summer plant crop to such a degree that the incidence of precocious fruiting for the following summer can be as high as 50 - 70%. This breakdown in crop control can seriously affect farm management and returns through inefficient harvesting and substantial yield losses caused by sunburn and overripe fruit. 2-(3-chlorophenoxy) propionic acid (Fruitone CPA) or paclobutrazol (Cultar) were applied as foliar sprays at various rates, application volumes and timings in an attempt to limit sucker growth rate to a degree that precocious flowering was inhibited. In a series of five trials over a period of four years, it was found that the seasonal timing of Fruitone CPA applications was a critical factor. Correctly timed Fruitone CPA applications reduced the incidence of precocious Summer fruit from an average 35.3% to 8.5%, while Cultar was less effective with a reduction from an average 46.1% to 29.0%. It was concluded that Fruitone CPA applied at a maximum of 160 ppin active constituent in 2,000 L/ha in late March was the most effective treatment.