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

<p> 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.  </p>