Page 27 - FRUTAS DEL TRÓPICO

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RepRoductive physiology of mango

More time must pass after pruning before stimulating flowering if paclobutrazol is not
used (Table 2). It is easier to stimulate flowering of ‘Haden’, ‘Keitt’, ‘Irwin’, or ‘Kent’ due to the

fact that the stems become sufficiently mature to elicit a floral response about 5 months after

pruning in these cultivars. In contrast, ‘Tommy Atkins’ is more difficult to stimulate to flower

in the American tropics. This is due to the added month of rest necessary prior to eliciting a

flowering response (Tables 1 and 2).

Nitrate salts applied to foliage stimulate shoot initiation (see reviews in Davenport and

Nuñez-Elisea, 1997; Davenport, 2000). Floral stimulation with nitrate application must be

accomplished at the time periods indicated in Tables 1 and 2, depending upon cultivar, night

temperatures at the time, and upon whether paclobutrazol is being utilized or not. Application
of nitrate earlier than recommended usually results in vegetative instead of flowering flushes.

Any nitrate salt or thiourea works to stimulate initiation of flowering shoots when administered

at the proper time (Nuñez-Elisea, 1988; Tongumpai et al., 1997). Calcium or potassium ni-

trate should be spray applied to the undersides of leaves throughout the tree canopy without

adjuvant as a 4% (W/V) solution whereas ammonium nitrate should be applied at 2% (W/V).

If ready to respond, the entire tree will initiate growth immediately with new shoots visible by

10 days. Repeat biweekly sprays and observations may be needed until the desired flowering
response is observed. Low night temperatures occurring during the scheduled spray time may

result in earlier stimulation of flowering. It is advisable to spray and observe only a few sam-

ple trees from the earliest pruned group in the orchard before spraying the entire orchard to

reduce the cost of repeat sprays. If a vegetative response is observed, it means the stems are

too young, likely due to a later flush of growth than anticipated following the pruning event.

One is advised to wait three to four weeks before applying nitrate to a new set of such test

Universidad Autónoma de Chiapas