Transcript 2. climatic adaptbilty

CLIMATIC ADOPTABILITY /REQUIREMENTS OF
BANANA
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INTRODUCTION

The major banana growing areas of the world are geographically
situated between the Equator and latitudes 200 N and 200S.

Climatic conditions in these areas are mainly tropical, with
comparatively small temperature fluctuation from day to night
and from summer to winter.
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The banana growing areas of subtropics are situated between
200 and 300 North or south of the equator.

The main climatic characteristic in the subtropics are the wide
temperature fluctuations between day and night and between
summer and winter, the high and the low rainfall which is also
poorly distributed.
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Bananas perform very well under humid tropical conditions but
can be cultivated successfully even under humid or semi arid sub
tropical conditions.

The growth and yield of most of the varieties are better at a
temperature range of 25-35°C though they can be cultivated at a
temperature range of 10-40°C.
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A suitable banana climate is a mean temperature of 26.67°C and
mean rainfall of 10 cm per month. There should not be more than
3 months of dry season.

Under cooler climates the crop duration is extended. The
shooting and bunch development gets affected at temperature
less than 10°C.
Cont.
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The growth of the banana plant responds quickly, within a matter
of an hour or two to changes in air temperature. All growth ceases
as soon as the temperature of the surrounding air falls below 11°
C.
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As long as the temperature remains 11° C, no growth whatsoever
takes place. As the air temperature rises above 11° C growth
starts and the growth rate increases gradually at first, and then
with rising temperatures, more and more rapidly.
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The biggest increase in growth rate for every degree that the
temperature rise appears to lie between approximately 19° C and
23° C.
Cont.
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The daily growth at 23° C is, in fact, about double that at 19° C.
With further rise in temperature, the growth continues to increase,
but more and more slowly as high levels of temperature are
reached.

In the experiments conducted, no falling off or even leveling off of
the growth rate was observed.
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Cool weather and prolonged drought retard growth. Banana plants
produce only one leaf per month in winter, 4 per month in summer.
If low temperatures occur just at flowering time, the bud may not be
able to emerge from the stem.
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If fruits have already formed, maturity may be delayed several
months or completely suspended. If only the leaves are destroyed,
the fruits will be exposed to sunburn.

Smudging, by burning dry trash covered with green clippings to
create smoke, can raise the temperature 2 to 4 degrees.

Flooding the field in advance of a cold snap will keep the ground
warm if the brief chill weather is prevailed.

The brief frosts kill the plants to the ground but do not destroy the
corm. A cooking banana, 'Plankel', survives winters in home
gardens in northern India.
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
Banana is cultivated under different conditions in India. The
temperature, Rainfall and Latitude details of banana growing states in
India.
State
Andhra Pradesh
Latitude ° N
Temp° C
Region
Rainfall (Cm)
16-18
16-43
Coastal
100
Telangana
81
Rayalaseema
68
Assam
25-27
16-38
-
252
Bihar
22-25
10-46
-
137
Karnataka
14-28
13-18
Coastal
326
South
124
North
69
Kerala
10-14
16-38
-
301
Maharashtra
19-22
13-41
-
92
Tamil Nadu
10-12
16-41
-
102
Uttar Pradesh
25-28
7-43
East
102
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
Banana comes up well at altitudes ranging from sea level to 1500
m above mean sea level. 'Dwarf Cavendish' and the 'Red' banana
are particularly sensitive to cold, whereas the dwarf cultivar
'Walha', or 'Kullen', of India is successful up to 4,000 ft (1,220 m) in
the outer range of the Western Ghats.

'Vella vazhai' is extensively cultivated in the Lower Pulneys
between 3,200 and 5,500 ft (975 and 1,616 m).

At higher altitudes, only few varieties like ‘hill bananas’ can be
grown successfully as is being practiced in Pulney and Shevroy
hills of Tamil Nadu.

They are prone to wind damage in areas where severe winds are
experienced. In such areas ‘Dwarf Cavendish’ can be tried for
cultivation.
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Wind is detrimental to banana plants. Light winds shred the
leaves, interfering with metabolism; stronger winds may twist and
distort the crown.

Winds to 30 mph break the petioles; winds to 40 mph will topple a
pseudostem that is supporting the weight of a heavy bunch
unless the stem is propped, and may cause root damage in non
fruiting plants that are not blown down; winds of 60 mph or over
will uproot entire plantations, especially when the soil is saturated
by rain.

Windbreaks are often planted around banana fields to provide
some protection from cold and wind. Hot winds blowing in high
speed during the summer month's shred and desiccate the
leaves.
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
Cyclones and hurricanes are devastating and the latter were the
main reason for the shift of large scale banana production.

Hail results from powerful convection currents in the tropics,
especially in the spring, and does much damage to bananas.
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Stagnation of water is injurious and may cause diseases like
Panama wilt. In coastal areas of Andhra Pradesh and Tamil Nadu
the cyclonic wind damages the plantations.

Hence it is advisable to select areas where mean temperature is
around 25-30° C with a mean annual rainfall of 100 mm per
month.
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EFFECTS OF LOW WINTER TEMPERATURES
The problems which result in a banana plantation from low
winter temperatures serve to only emphasize the importance of
adequate heat as a factor, in banana production.
The most important of these are 'choke throat' 'November
dump' and frost damage.
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CHOKE THROAT
Symptoms
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Choke throat is a physiological disorder of bananas. It is also known
as choke, choking or choked throat.
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In its most severe form the bunch fails to emerge from the top of the
pseudostem and instead bursts through the side of the pseudostem.
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In less severe cases the top 1 or 2 hands become trapped in the
throat of the plant leading to badly misshapen fruit.Because the bunch
is not 'thrown' clear of the throat it is both difficult to cover with bunch
covers and more susceptible to sunburn damage.
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Bunches which experience difficulty in emergence usually have
several leaves closely 'bunched' together at the top of the
pseudostem.
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CAUSES
Choke throat is seasonal in nature. It is usually worst in the winter
and early spring following cold weather. However, it can also occur
following periods of water logging or severe water stress and
following wind storms.
Two factors contribute to the actual difficulty in bunch emergence.
Firstly there is a reduction in the elongation of internodes of the true
stem bearing the bunch inside the pseudostem (pseudo = false).
Secondly, the stiffness of the leaf bases at the top of the pseudostem
can prevent proper bunch emergence
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Control
• Select taller varieties, which are less susceptible
to choke, throat, eg Williams.
• Choose a warm environment, one which is well
protected from frosts and strong winds.
• North Queensland has less problems with choke
throat than southern Queensland. Slopes facing the
north and north west are usually warmer.
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
Control time of bunching to avoid cold weather prior to bunching.
Plants bunching in the late spring to mid autumn are less
affected.

Good on-farm drainage measures including mounding of rows.

Regular irrigation to avoid water stress particularly during hot-dry
weather.
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Higher nitrogen rates are thought to be beneficial
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NOVEMBER DUMP
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Cold temperatures also have a marked effect on bunch
development. When the flower initiation occurs during the winter, a
characteristically a peculiar bunch can be expected.
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The November dump bunch is small and composed of hands of
uneven size and often deformed fruits.
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The smaller fingers on the hands are, in many cases, fuller at the
flower end and thinner at the stalk end.
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The flower end is often black, rough and cracked and during a good
rainy season, fungal diseases further damage these fruits
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Another common symptom is the cone-shaped
protuberance at the flower end.
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This protuberance is pale green in color. The
amount of misshapen fruit as Novemberemerging bunches varies from year to year.
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It must be stressed that November dump
symptoms are caused by cold temperatures and
they are not mineral deficiency or drought
symptoms.
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A good orchard practice is to cut down all the
plants producing severe November dumps.
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REFERENCE:
Veeraraghavathatham , D., M.Jawaharla,
S.Jeeva and R.Rabindran. 1996. Scientific fruit
culture.
 Chattopadhyay, 1994. A text book on pomology.
Kalyani publishers. Ludhiana.
 Nakasone, A.Y. and R.E. Paul, 1998. Tropical
fruit. CAB international publishing ltd.
 Bal J.S., 1997. Fruit growing, Kalyani publishers.
Ludhiana
 Singh, S.P. 1995. Commercial fruits. Kalyani
publishers. Ludhiana.
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ASSESSMENT
1. _________and prolonged drought retard growth. Cool
weather.
2. The shooting and bunch development gets affected at the
temperature ______
a). 10 - 20° C
b). More than 20° C c). Less than 10° C
3. _______ and the 'Red' banana are particularly sensitive to
cold.( Dwarf Cavendish')
4. _________ varieties are most susceptible to choke throat
disorder.
a). Tall varieties
b). Dwarf varieties
5. November dump symptoms are caused mineral deficiency or
drought symptoms (True/ False)
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