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.

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.

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.

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Cont.

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.

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.

The biggest increase in growth rate for every degree that the

temperature rise appears to lie between approximately 19° C and

23° C.

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Cont.

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.

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 Latitude ° N Temp° C Region Rainfall (Cm)

Andhra Pradesh 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

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.

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

Choke throat is a physiological disorder of bananas. It is also known

as choke, choking or choked throat.

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.

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.

Bunches which experience difficulty in emergence usually have

several leaves closely 'bunched' together at the top of the

pseudostem.

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Symptoms

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.

Higher nitrogen rates are thought to be beneficial

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NOVEMBER DUMP

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.

The November dump bunch is small and composed of hands of

uneven size and often deformed fruits.

The smaller fingers on the hands are, in many cases, fuller at the

flower end and thinner at the stalk end.

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.

This protuberance is pale green in color. The

amount of misshapen fruit as November-emerging

bunches varies from year to year.

It must be stressed that November dump symptoms

are caused by cold temperatures and they are not

mineral deficiency or drought symptoms.

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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