Agriculture Reference
In-Depth Information
are lanceolate and curl, and two regular rows of ovules, compared with four
irregular rows in
M. balbisiana
.
Using and scoring 15 morphological characters
allows the relative contribution of the two species to be determined in hybrid
cultivars. Triploids and tetraploids are larger and more robust than diploids.
Origin and distribution
The primary centre of origin is thought to be Melanesia (Malaysia, Indonesia,
the Philippines, Borneo and Papua New Guinea);
M. acuminata
Colla. has
seeded fruit. Dessert cultivars were developed from it via parthenocarpy and
sterility, aided by human selection and vegetative propagation.
M. balbisiana
Colla. also has a wild, seeded fruit, is more suited to drier areas and occurs
from India to New Guinea and the Philippines, though absent from central
Melanesia (Espino
et al.
,
1992). It was similarly taken into cultivation, with the
selection of natural diploid, triploid and tetraploid hybrids.
ECOLOGY
Soil
Deep friable loams with natural drainage and no soil compaction are preferred.
Soils with poor percolation due to excess of clay or with an excessive amount
of sand should be avoided, as well as soils with high amounts of gravel. Soils
having pH between 4.5 and 7.5 are used, although 5.8-6.5 is recommended.
Soil textures ranging from sands to heavy clays are used. A granular soil
structure is the preferred for better water movement and root growth, with
high organic matter and fertility ensuring high yields. Most exported bananas
are produced on highly fertile alluvial loams. Plantains also do best in this type
of soils, but they will do better than the AAA dessert banana in lower-quality
soils; apparently the 'B' in their genome is responsible for this adaptability.
Soil depth should be around 1.0-1.2 m, with no superfi cial water tables or
impermeable layers. Soil drainage is essential since, although the plant prefers
moist soil, it does not tolerate standing water. Flooding for a week will kill most
banana plants (Duarte, 1991). Banana will tolerate some salinity: 300-350
mg/l of chlorine and up to 1500 ppm total salts.
Climate
Rainfall
Bananas require a regular water supply that matches or slightly exceeds the
free-water evaporation rate. Irrigation is essential for high yields if rainfall is
less than evaporation and it also provides the advantage of fertilization via the
