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Agriculture > Tuber Crops
> Tapioca (Manihot esculenta)
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About the Crop
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Tapioca (Manihot esculenta) is a Euphorbiaceous woody shrub native to South
America, cultivated extensively as an annual crop in tropical region for its edible
starchy tuberous roots. The roots are nutritious and wholesome, and are used as
a supplementary food as it is a major source of carbohydrates. The tapioca plant
gives the highest yield of food energy per cultivated area per day among crop plants,
except possibly for sugarcane. Apart from starch, tapioca roots also contain significant
amounts of calcium, phosphorus and vitamin C.
In Kerala, cassava is a secondary staple food and is known as the poor man’s vegetable.
Boiled cassava is normally eaten with fish curry (kappayum meenum) or meat, and
is a traditional favorite of many Keralites. Kappa biriyani -cassava mixed with
meat is a popular dish in central Kerala. Various processed products of export importance
are also made from tapioca.
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Climate & Soil
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Tapioca grows and produces best under warm humid tropical conditions where rainfall
is well distributed and fairly abundant. It can also be grown under irrigation where
rainfall is low. Its outstanding characteristic in terms of moisture requirements
is the ability to withstand fairly prolonged periods of drought. However, at the
time of planting there must be sufficient moisture for the plant to establish itself.
The crop cannot withstand cold and is killed by frost.
The crop grows well in well-drained laterite, gravelly and sandy loam soils. Heavy
and rocky soils are less suitable because they restrict root development. The crop
cannot survive waterlogged conditions and in such areas, it must be planted on mounds
or ridges that permit drainage. The crop can also be gown on hill slopes and on
wastelands of low fertility.
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Varieties
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H-97: This is a semi-branching
variety, tolerant to mosaic disease with duration of 10 months. But the harvest
can be prolonged even up to 16 months. The starch content is 30%.
H-165: This is a non-branching
type with poor cooking quality having eight months duration. It is tolerant to mosaic
but susceptible to wilt disease. The starch content is 24.5%.
H-226: This is a semi-branching
type with medium cooking quality having 10 months duration. It is moderately susceptible
to mosaic. The starch content is 29%.
M-4: This is an erect type
with excellent cooking quality having 10 months duration. The starch content is
29%.
Sree Visakham: This is a semi-branching
type with yellow coloured flesh having 10 months duration. It shows high tolerance
to mosaic and low susceptibility to pests like red mites, scale insects, thrips
etc. The starch content is 26% and vitamin A 466 IU.
Sree Sahya: This is a predominantly
semi-branching type with 10 months duration. It shows high tolerance to mosaic and
low susceptibility to pests like red mites, scale insects, thrips etc. The starch
content is 30%.
Sree Prakash: This has seven
months duration and the yield potential is 30-40 t/ha.
Kalpaka: This is a non-branching
type with six months duration and is suited as an intercrop of coconut in reclaimed
alluvial soils of Kuttanad.
Sree Jaya: This is an early
variety with seven months duration and excellent cooking quality. Tuber contains
24-27% starch and is low in cyanogens.
Sree Vijaya: This is an early
variety with 6-7 months duration and excellent cooking quality. Tuber contains 27-30%
starch and is low in cyanogens.
Sree Harsha: This has 10 months
duration and good cooking quality. Tuber contains 34-36% starch. They are non-bitter
and ideal for culinary purposes and the high starch content makes it suitable for
preparing dried chips.
Nidhi: This is a high yielding
early variety with 5.5-6 months duration. It is tolerant to mosaic and moisture
stress. Tuber contains 26.8% starch and 20 ppm HCN.
Vellayani Hraswa: High yielding
early variety with 5-6 months duration. It cannot tolerate drought. The cooking
quality is very good. Tubers contain 27.8% starch and 53 ppm cyanogen.
Sree Rekha: It is a top cross
hybrid with 10 months duration. Tubers contain 28.2% starch with excellent cooking
quality.
Sree Prabha: It is a top cross
hybrid with 10 months duration. Tubers contain 26.8% starch with good cooking quality.
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Propagation & Planting
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Planting material
Tapioca is propagated by stem cuttings. Select mature healthy stems free from diseases
or pests. Discard about 10 cm from the lower mature and about 30 cm from the upper
immature end. Stems should be cut into setts of 15-20 cm length using a sharp knife.
About 2000 stems are required for planting one hectare. Harvested stems are to be
stored vertically in shaded and well-aerated places. Spraying dimethoate (0.05%)
on the stem will control scale insects.
Season
The main planting seasons are April-May with the onset of southwest monsoon and
September-October with the onset of north-east monsoon. Planting can also be done
during February-April, provided sufficient moisture is made available through irrigation.
For maximum tuber production, April-May planting is preferred because the crop can
effectively utilize both the monsoons. The second best season is September-October.
Minisett planting technique for quality planting
material
For producing minisetts, mature, disease free stems preferably those obtained from
indexed meristem culture should be selected. Two node cuttings are taken from these
stems using a sharp hack-saw. Top one-third portion is usually discarded in the
traditional system, however in the minisett technique, it is fully utilized. The
tip of the stem (about 5 to 6 cm long) is carefully cut without causing damage.
For preventing dehydration, it is advisable to place the tip cuttings in water.
The stem just below the growing tip is very tender with prominent axillary buds.
Hence, from this portion, cuttings with four nodes are taken instead of two as the
latter may easily get dried up.
Preparation of nursery:
Select an area with well drained soil and irrigation facility. Shade net house of
35 per cent shade is ideal for the germination and growth of minisetts. Mark out
the length and breadth and make raised beds of soil : sand mixture in equal proportion.
The beds could be of convenient length and width not exceeding 1 m. An area of 220
m2 nursery is required for producing minisetts for planting one hectare
of land. Two node cuttings are planted end to end horizontally, about 5 cm deep
inside the soil, with the buds facing either sides. Tip cuttings and four node top
setts should be planted erect at 5 cm x 5 cm spacing to prevent decay due to excess
moisture in these tender parts. Minisetts would sprout in a week’s time. Mosaic
virus infected plants, if any found, should be rogued off as soon as such symptoms
are expressed, to keep the nursery disease free. The minisetts will be ready for
transplanting in about three to four weeks time. After the basal application of
recommended manure in the main field, ridges of 30 cm height are taken with a spacing
of 45cm between the ridges and planting is done on the ridges at a spacing of 45
cm. Multiplication ratio by this process is enhanced to 1: 60 as against the traditional
method 1:10.
Land preparation and Planting
Before planting, plough the field 2-3 times or dig to a depth 25-30 cm depending
upon soil type to establish a deep porous field in which the setts are to be planted.
Pit, flat, ridge or mound method of planting can be adopted depending upon soil
type, topography of land and elevation so that waterlogging is avoided. Pit followed
by mound is found to be the best method of planting. Plant the cuttings vertically
after smoothening the lower cut end, at a depth not exceeding 4-6 cm. Adopt square
method of planting at a spacing of 90 x 90 cm @ one cutting per pit. It is preferable
to adopt 75 x 75 cm spacing for non-branching varieties like M-4.
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Intercultural operations
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Gap filling
Gap filling should be done within 15 days after planting preferably with longer
setts of 40 cm length. Sree Visakha is a choice variety recommended as an intercrop
in coconut gardens. Optimum plant population is 8000 plants per ha with 90 x 90
cm spacing.
Manuring
Cattle manure or compost may be applied at 12.5 t/ha during the preparation of land
or while filling up the pits so as to provide about 1 kg of organic manure per plant.
Apply fertilizers N:P2O5:K2O at the rates (kg/ha)
shown below:
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H-97 and H-226
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75:75:75
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H-165, Sree Visakham, Sree Sahya
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100:100:100
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M-4 and local
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50:50:50
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N and K2O may be applied in three split doses, i.e., 1/3 basal, 1/3 two
months after planting and 1/3 three months after planting. Dose of P2O5 can be reduced
to half where the crop is grown for more than 3 years under full dose of recommended
fertilizers, since under such situation there would be build up of soil P.
For August-September planted tapioca, apply half N, full P2O5
and half K2O basally with first digging and weeding. The remaining quantity
of N and K2O may be applied 45 days after planting at the time of intercultivation.
Note: N:P2O5:K2O at 50:50:100
kg/ha is recommended for Sree Visakam when grown as an intercrop in coconut garden.
Higher levels of N tend to increase HCN content of the tubers.
Soil application of Mg as MgSO4 @ 20kg/ha and Zn as ZnSO4 @ 12.5 kg/ha
in small channels around the mounds within 2 months of planting
cassava providing an interval of 2 weeks between the application
of these fertilizers enhance tuber yield and quality.
Irrigation
Under conditions of well-distributed rainfall, tapioca grows well as a rainfed crop
and irrigation is not necessary. However, the crop has to be irrigated to provide
sufficient moisture under conditions of prolonged dry periods after planting. Furrow
irrigation and alternate furrow irrigation methods can be adopted to irrigate tapioca.
Alternate furrow irrigation once in 20-27 days helps to save water and labour with
out affecting yield. When the crop is grown under irrigation, yield increase of
150-200% over the rainfed crop has been observed.
Weed control
Keep the field free of weeds and maintain soil loose by 2-3 shallow diggings or
hoeing up to 90 days after planting followed by light earthing up. Retain two shoots
on each plant in opposite directions and remove excess shoots about 30 days after
planting.
Intercropping
Tapioca is planted at a spacing of 90 x 90 cm and it takes about 3-3.5 months time
to have enough canopy to cover the land. So it is possible to have an intercrop
of groundnut during the early stages of tapioca crop. Bunch varieties like TMV-2,
TMV-7, TG-3, TG-14 and Spanish improved are preferred for intercropping in tapioca.
The best season for sowing groundnut is May-June.
Immediately after planting of tapioca setts, groundnut seeds are sown at a spacing
of 30 cm between rows and 20 cm within rows, so that two rows of groundnut can be
accommodated in between two rows of cassava. A seed rate of 40-50 kg/ha is recommended
for dibbling one seed per hill. Only well-matured and bold seeds are to be selected
for sowing. In acid laterite soils of Kerala, apply 1000 kg/ha of lime as basal
dressing. A basal dose of 50:100:50 kg N:P2O5:K2O
per ha should be given uniformly to both the crops. One month after sowing of the
seed, 20 kg each P2O5 and K2O and 10 kg N / ha
may be given to the intercrop along with earthing up. Once pod formation has started
(i.e., 40-45 days after sowing) the soil should not be disturbed, as it will affect
the pod development adversely. The groundnut crop matures in 105 to 110 days. After
the harvest of pods, the haulms are incorporated in the soil along with a top dressing
of 50 kg each of N and K2O per ha for the main crop. By adopting this practice,
20-25% additional income can be obtained.
In sandy areas intercropping tapioca with cowpea / groundnut / black gram / green
gram may be recommended giving a spacing of 20 cm on both sides of the ridges. The
non-trailing grain cowpea variety V-26 is recommended as a companion crop along
with tapioca. For a pure crop of tapioca or for a cropping system involving tapioca
as the main crop and the pulse crop suggested above, the field may be irrigated
once in 36 days to a depth of 5 cm. This recommendation is for shallow water table
situations. For deep water table situations, the crop may be irrigated once in 24
days to a depth of 5 cm.
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Plant Protection
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Diseases
Cassava mosaic disease (CMD)
The disease is transmitted by a white fly Bemisia sp. As a rule, only stem cuttings
from disease free plants should be used for planting to minimize the spread of the
virus disease. For this purpose, tagging of disease free healthy plants for selection
as planting materials must be practiced from September to December. All plants showing
even very mild symptoms must be rejected. Mosaic tolerant varieties such as H-97
may be used to minimize economic loss of tubers.
Production of disease free planting material of
tapioca through nursery techniques
Setts of 3 to 4 node cuttings from apparently disease free plants are collected
and planted in the nursery at a very close spacing of 4 x 4 cm so that about 500
setts can be accommodated in one square metre land. Daily watering of the setts
has to be done for the first 10 days and on alternate days afterwards. Screening
of CMD symptoms may be started 10 days after planting. Setts showing even mild symptoms
are to be removed and burnt. This must be continued up to 20-25 days, by that time
healthy seedlings can be transplanted to the main field. Supplementary irrigation
may be given in the transplanted field till they get established. Screening for
disease symptoms and rouging of infested plants may be continued in field at weekly
intervals up to harvest. The selected healthy stems are again cut into minisetts
and subjected to nursery and field screening. By adopting this technique it is possible
to produce healthy plants.
Leaf spot
Spray 0.2% zineb or 1% Bordeaux mixture for control of leaf spot.
Bacterial blight
Bacterial blight is a disease noted in severe proportion in certain parts of Kerala.
Chemical control is not effective. Use of resistant or tolerant varieties is the
only method of control. Among improved varieties, H-97, H-226, H-1687 and H-2304
are tolerant to the disease while H-165 is highly susceptible. Among the local varieties,
M-4, Paluvella, Pichivella, Parappilppan, Anamaravan etc. are tolerant to the disease.
Pests
Red spider mites and scale insects
Red spider mites in the field and scale insects under storage are important pests
of tapioca. Under field conditions light infestation of mites can be controlled
effectively by spraying the crop with water at 10 days interval from the onset of
mite infestation. In the case of very severe infestation, the crop can be protected
by spraying 0.05% dimethoate or methyl demeton at monthly intervals from the time
of appearance of mites.
The stem may be sprayed with 0.05% dimethoate before storing as a prophylactic measure
against the scales.
Termites
To control termites infesting planted setts, sprinkle a little of carbaryl 10% or
chlorpyrifos in the mounds prior to planting.
Management of storage pests
Treating chips with granular salt (3%), sun drying thoroughly and storing in gunny
bags in godown are very effective against Araecerus fasciculatus and Sitophilus
oryzae.
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Harvest
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Tapioca becomes ready for harvest 9-10 months after planting. Hybrid varieties like
H-226, H-97 and H-165, when grown under recommended management practices have recorded
yields up to 40-50 t/ha of raw tuber. The local varieties and M-4 yield on an average
12-14 t/ha of tuber.
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