Agriculture Reference
In-Depth Information
irrigation water. Areas with very high rainfall may be too overcast for optimum
photosynthesis, have more disease problems and require extensive drainage.
The plantain group is less susceptible to water stress than dessert bananas
(Belalcazar, 1991), and this is another reason why small farmers grow them
around their houses. Plantains do well with about 30 mm weekly rainfall in
the cof ee region of Colombia.
Temperature
A temperature range of 15-38°C occurs in most production areas, with
the optimum temperature being ~27°C. The optimum for dry-matter
accumulation and fruit ripening is about 20°C and for the appearance of
new leaves about 30°C. Growth ceases at 10°C and can lead to 'choke-
throat' disorders, where infl orescence emergence is impeded and poor fruit
development occurs. Temperatures less than 15°C can be withstood for short
periods, while temperatures less than 6°C cause severe damage (Turner,
1994), and temperatures below 4°C result in irreversible damage. Frost
causes rapid death. At temperatures above 38°C growth stops and leaf burn
occurs. Plants growing in the subtropics produce fewer leaves per year than
those in the tropics and take longer to produce and develop fruit (Table 8.2).
Sucker emission and development are also slower. Bananas grown at higher
elevations that have lower temperatures tend to produce sweeter fruit, because
of cooler nights. In certain cooler areas, such as the Canary Islands, bananas
are produced in plastic greenhouses.
Plantains and cooking bananas are grown at sea level but also at higher
elevations in Latin America, Asia and Africa. In many cases, they are grown
as subsistence crops and are planted even at 2000 m above sea level in places
where mean minimum temperatures are not below 15°C and the absolute
minimum does not drop below 8°C. Clonal dif erences do occur in the ability
to adapt to cooler temperatures. In Colombia, an important producer of
plantains, commercial production occurs from sea level to 1350 m, though
clones such as 'Harton' are not planted above 800 m. Lower temperatures
Table 8.2.
Phenological differences between cultivars of Cavendish subgroup
ratoon plantation in the humid tropics (Honduras: cv. 'Grand Nain', Stover and
Simmonds, 1987) and subtropics (South Africa: cv. 'Williams', Robinson and Nel,
1985; Robinson and Human, 1988).
Humid tropics
Subtropics
Mean number leaves per month (warm/cool
season)
3.5/2.5
4/0.5
Total leaves per year
40
25
Planting to harvest (months)
9-11
15-20
Harvest to harvest (months)
6-8
11-13
Flowering to harvest (warm/cool season, days)
98-117
120-204
