MANGO - Tropical Fruits - page 256

Fig. 10.3. Effect of temperature during pollen development on mature pollen
viability (Issarakraisila et al. , 1993).
Temperature plays a key role in mango fl owering, and the response varies
with cultivar. For fl ower induction, the ideal seems to be around 10-15°C. The
cooler temperatures in the subtropics are normally followed by fl owering, with
temperatures ~5°C inducing more male fl owers on the infl orescence. Panicle
growth does occur at 12.5°C, when no vegetative shoots are produced (Schaf er
et al. , 1994). However, low temperatures (<16°C) lead to fl ower deformation,
loss of pollen germination (Fig. 10.3) and slow pollen-tube growth and induce
ovule abortion, with the production of seedless fruit (Young and Sauls, 1979).
For each 125 m increase in elevation and each degree of latitude north or
south of the equator, fl owering is delayed by 4 days.
Light
Shading can prevent or delay fl ower-bud formation, and a higher percentage
of perfect fl owers occur on the side of the tree receiving direct sun. Mango
trees have a signifi cant number of shaded leaves and pruning can increase
light penetration to these leaves, but how this infl uences yield is unknown;
more light may result in larger fruit. Fruits also have a brighter red skin colour
under higher light (Schaf er et al. , 1994).
Photoperiod
Photoperiod seems to play no role in fl ower induction (Nuñez Elisea and
Davenport, 1995). Flowering occurs at all photoperiods from 10 to 14 h at
an inductive temperature of 18°C day and 10°C night. The failure of biennial
cultivars to fl ower in the 'of season' in the subtropics and fl owering occurring
at the equator several times a year indicate a day-neutral habit.