Agriculture Reference
In-Depth Information
Fig. 12.2.
Effect of temperature on leaf and root growth (redrawn from Sanford,
1962).
Where topographic variation exists, changes in elevation provide a
means of achieving a desirable range of temperature conditions (Fig. 12.3).
Near the equator, the highest yields and fruit of the best quality are generally
obtained at higher elevations. In Kenya, an equatorial country, pineapple
is grown at more than 1400 m, while on Mindinao, the Philippines (8° N),
most pineapple is grown at an elevation of 250 m or higher. While elevation
provides an opportunity to provide an ideal environment for pineapple in
the tropics, economics, particularly labour costs, often determines where the
crop is grown. Thailand (~15° N) is the world's largest producer of pineapple,
yet most of the crop is grown near sea level in this warm tropical country.
South Africa and southern Queensland, Australia represent the extremes of
the climatic range over which pineapple is grown, and winter temperatures
severely restrict growth rates. In southern Queensland, fruit initiated by forced
fl owering during the 3 coldest months all mature within about 1 month, as
growth resumes as spring temperatures increase (Fig. 12.3). In South Africa
and southern Queensland, minimum temperatures occasionally approach
or reach freezing point for short durations, while in most other areas where
pineapple is grown winter temperatures rarely fall below 10°C.
Cool night temperatures coincident with shortened day length stimulate
fl oral induction if the plant is of sui cient size. Cool temperatures also increase
