Agriculture Reference
In-Depth Information
do reduce yields signifi cantly, making commercial production uneconomic. It
is estimated that the vegetative cycle is extended by 10 days for every 100 m
increase in elevation (Belalcazar, 1991). At higher elevations, the form of the
fruit bunch changes, with hands becoming more separated.
Wind
Bananas and plantains are very susceptible to wind damage. In all producing
regions, moderate winds between 20 and 50 km/h cause moderate to severe
tearing of the leaves. This leaf-tearing can reduce productivity, but as long
as there is no signifi cant loss of foliar surfaces, it does not normally have a
major ef ect. This tearing does reduce plant transpiration when maximum
daily water stress occurs, while net photosynthesis is little af ected (Belalcazar,
1991), giving higher photosynthetate production by unit of water transpired.
This benefi cial ef ect may be important during the dry season. The problem
with winds above 50 km/h
is that they cause loss of leaf pieces, break the
pseudostem or uproot the plants, in the latter two cases the crop is lost until
the ratoon suckers complete their cycle. In certain areas of Central America,
a phenomenon called 'blow down' is frequent; this is caused by gusts of
high-velocity winds that unexpectedly hit certain areas and break all tall
pseudostems, producing almost the same ef ects as a hurricane but in a
limited area.
Light
For dessert bananas, as well as for plantains, solar radiation should be as
high as possible for best growth and yields, although fruit sunburn can occur,
especially if water supply is low; petioles can also be burnt. Shaded or overcast
conditions extend the growth cycle by up to 3 months and reduce bunch size
(Fig. 8.1). For plantains grown under lower radiation levels, the plants tend to
be taller. Plant density plays a role in relation to light, since denser plantings
intercept more light at the top but there will be less radiation at ground level,
reducing sucker production.
Photoperiod
No evidence exists that photoperiod infl uences fl owering. Increasing the
photoperiod from 10 to 14 h increases the rate of new leaf appearance,
probably due to more photosynthesis.
GENERAL CHARACTERISTICS
Plant
This 2-9 m perennial herb has an underground, compressed stem or corm
that is the real stem. The visible part that looks like a stem (pseudostem)
