Page 56 - FRUTAS DEL TRÓPICO

56 Frutas del trópico

timely flowering in cool temperatures or when sprayed with nitrate as described above. Figure
4A demonstrates floral initiation that was stimulated by a foliar spray of 4% potassium nitrate

five months after tip pruning in warm, tropical conditions. Only one vegetative growth flush

occurred after tip pruning. In contrast, Figure 4B displays a tree with a leaf nitrogen content of

1.6% that produced a second vegetative flush soon after the first, resulting in vegetative ins-

tead of reproductive shoot initiation when stimulated to grow five months after pruning using

the same nitrate spray treatment. Pruning stems greater than one cm diameter encourages

second flushes, and pruning larger branches and scaffold limbs assure frequent subsequent

flushes of vegetative growth.

Stems of bearing-size trees can vary in age due to asynchronous vegetative growth of
the canopy (Fig. 5A). This lack of uniform stem age causes asynchronous flowering in various

sections of the canopy that requires multiple passes through the orchard when harvesting fruit.

Tip pruning trees (Fig. 5B) forces a synchronized flush of vegetative shoots from pruned stems

(Fig. 5C) throughout the tree canopy. If this is the only flush to occur for five to six months fo-

llowing pruning, the subsequent synchronous growth will be reproductive, even in warm tem-

peratures >20 °C (Fig. 5D). Tip pruning is, thus, done to assist in uniform flowering response

in a flowering management program, to impart a desired shape to the canopy, and to improve
the productivity of bearing trees by significantly increasing the number of bearing stems.

Tip pruning is best done with sharp machetes and ladders or other means where labor

is available to reach the tops of trees in the tropics (Fig. 6A). A variety of pruning machines

(Fig. 6B) are also available for rapid pruning of large orchards, but they are expensive unless

several growers share the cost. One should prune most of the terminal stems in the canopy

for best results (Fig. 5B). The cuts should be no deeper than the third intercalary unit in order

to discourage unwanted second flushes. In the Caribbean islands and Central America, tip

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