BY CSKHPKV

2. TAPIOCA (Cassava) : Manihot esculenta Crantz.
Chromosome No : (2n = 2x = 36)
Family: Euphorbiaceae
Origin:North-Eastern Brazil
 Economic part of this plant are roots or tubers. Starch content in
cassava is highest among other tuber crops i.e. (25-40 %) Tubers
also contain a deadly poisonous chemical i.e. HCN. Upon sun
drying cyanide derivatives disappear from slices of cassava.

3.  Nigeria, Ghana, Brazil, Thailand, Indonesia and
India are the major growing country in world.
 In India crop is cultivated in southern peninsular
region, particularly in Kerala, Tamil Nadu and Andhra
Pradesh contributing 93% of area and 98% of
production in the country. Area under Tapioaca in
India is 207.59(000ha) and production is
4372.68(000MT)
 Kerala accounts for nearly 50% of total area under
cassava in India and is mainly grown as rainfed crop.
NHB (2014-15)

4.  It is a perennial shrub producing 5-10 cylindrical tubers per
plant.
 The stem is woody and variously branched. Two distinct
types are present – one without branching at the top and the
other with spreading nature.
 Cassava is monoecious in nature and cross-pollinated.
Female flowers are fewer in numbers and borne in the base
of inflorescence. Female flowers open about 10 days before
male flower anthesis.
 Tubers are composed of a thin peridium, white or purple
cortex known as rind and Central massive flesh rich in
starch (25-40%).

5.  Most of the crop improvement works on cassava are
done at the Central Tuber Crops Research Institute
(CTCRI), Thrivendrum.
 Sree Sahya: This is a non-branching and multiple
hybrid involving five parents, tubers are long and rind
is cream coloured; yield 35-40t/ha in 10-11 months.
 Sree Prakash: This is a short, non-branching, early
maturing (7-8 months) variety developed by clonal
selection; highly tolerant to Cercospora leaf spot; yield
35-40 t/ha .

6.  Sree Harsha: This is a triploid clone developed by crossing a
diploid with an induced tetraploid clone of ‘Sree Sahya’; plants
are erect and non-branching with tubers of good cooking
quality and high starch content (38-41%); yield 35-40 t/ha in 7-
8 months.
 Sree Jaya and Sree Vijaya : These are short-duration (6
months) clonal selection suitable for low land cultivation as a
rotation crop in paddy-based inter-cropping system; tubers are
with brown skin and purple rind and have good cooking
quality; yield 26-30 t/ha; susceptible to CMD.
 H-97, H-165 and H-226 are important hybrids.
 Sree Rekha, Sree Prabha, Nidhi ,CO-1 are new varieties.

7. Variety Pedigree Duration
(days)
Yield
(t/ha)
Starch
content(%)
Source
H-97 Manjuvella×brazilian
seedling
260-300 25-35 27-29 CTCRI
H165 Chadyamangalam vella×clone
similar to kalkalan
220-240 33-38 23-25 CTCRI
H226 Ethakka karuppan×M-
4(Malaysia)
260-300 30-35 28-30 CTCRI
Sree
Visakham(H
-1687)
Ac. No.1501 local×S-2312 270-300 35-38 25-27 CTCRI
Sree Prakash Selection from local
accessions
210-240 35-40 29-31 CTCRI
Sree Harsha Triploid 270-300 35-40 29-31 CTCRI
CO1 Clonal selection from atype of
Tiruchi
260-275 30-35 TNAU

8. Variety Pedigree Duration(day
s)
Yield(t/ha) Starch
content(%)
Source
CO2 Open pollinated
seedling from
Thiruvarur type,
Tanjore
260-275 30-35 _ TNAU
Coimbtore
CO3 Selection from OP
seeds from IITA,
Nigeria
240-270 35-40 _ TNAU
Coimbtore
Vellyani
Hrsawa
Clonal selection 155-180 43 _ KAU,
vellanikkara

10. Climate:
 Cassava is a tropical crop tolerant to drought and can not
withstand frost.
 It is grown in altitudes up to 2000 m, but performance is better in
lower altitudes.
 Though crop can be grown even in semi-arid conditions, growth
and productivity are better in warm humid climate with well
distributed rainfall (2000mm) annual rainfall .
Soil:
 Cassava grows on all types of soils, but saline, alkaline and ill-
drained soils are not suitable. Red sandy loam is mostly
preferred with pH ranging from 6.5-8.
 It is relatively a drought tolerant crop. Cassava can recover
from the damage of slight moisture stress of shorter duration
(short day plant).
 Crop is mainly grown in laterite soils in Kerala and black and
red soils in Tamil Nadu.

11. Planting season :
As an irrigated crop, cassava can be planted during any
part of year, but December-January planting is better.
As a rainfed crop, planting is done during April-May
before onset monsoon.
Propagation
Stem cuttings, usually called as sets, for planting are
taken from disease free stakes of 8-10 months maturity
having a thickness of 2-3 cm diameter.
Discard woody basal portion and tender top portion of
stem. Prepare sets of 15-20 cm length with a smooth
circular cut at the base and slanting cut at top for easy
identification of base and top. Sets prepared from stem
stored for 15 days with leaves give better sprouting.

12. Ideals sets
Ready for transplanting

13. Planting:
 Wider spacing of 90 x 90 cm is recommended for branching types
(H- 97 variety). Narrow space of 75 x 75 cm is for non-branching
types (H-165 variety).
 Two shoots per hill is found to be the best practice. Planted by
horizontal or vertical planting method.
 Cassava sticks can be planted at 45 degree angle or vertically.
Always put the sticks lower end in the ground.

14. Manuring:
 Cassava is a heavy feeder and crop is to be adequately
manures for getting high yield.
 Apply 125 tonnes of farmyard manure / ha as basal dose. A
fertilizer dose of 50 kg N, 50 kg P and 50 kg K / ha is
recommended at the time of land preparation.
Interculture:
 Pinching off excess sprouts emerging from sets is necessary in
cassava cultivation. This may be done 30-45 days after
planting.
 First inter-culture operation may be done sufficiently deep at
45-60 days after planting and a shallow inter-culture by way
of weeding or earthling up may be given one month after the
first.
 Irrigating crop at 25% available moisture depletion level,
could double tuber yield compared to irrigated crop.

15. Irrigation: Water stress condition should be avoided as it
is harmful to the crop. In the irrigated crop, irrigation is
given at 10-15days interval.
Harvesting and yield:
 The crop is ready for harvesting in 10-11 months after
planting. Short duration varieties can be harvested in 6-7
months.
 Delayed harvest results in deterioration of quality of tubers.
Harvesting is usually done by uprooting plants gently by
holding stem. After harvesting, stack stems vertically in well
aerated place for use in subsequent planting.
 Yield is 25-30 t/ha for short duration varieties and 30-40 t/ha
for other varieties.

16. Diseases:
 Brown leaf spot (Cercospora henningsi)- It is serious disease
in heavy rainfall areas.
Control- Spray the crop with 0.1% benlate.
 Cassava bacterial blight (Xanthomonas manihotis)- This
disease is characterized by the appearance of leaf spots, blight,
wilting, gum exudation and vascular necrosis of plants.
Control- Grow resistant varieties, select healthy and disease
free planting material.
 Cassava mosaic disease (CMD) - The chlorotic specks
appear on the leaves, which turn bright yellow and finally
cover the whole leaf lamina. It is transmitted through white fly.
Control- Spray either dimethoate or monocrotophos at
0.03%.

17.  Tuber rot (Phytophthora drechsleri)- Internal tissues
of tubers discoloured brown with foul smell and rot.
 Control: remove infected tubers from the field and
incorporate Trichoderma viridae into soil.
 Proper drainage.

18. INSECT-PESTS :
 Soft scale (Aonidomytellus albus)- Stems become weak and dry due to white
scale colonies, side branching with bushy appearnce. infested plants have poor
vaibility.
Control- Use scale free stem for planting, allow the setts in 0.05% solution of
Dimethoate for 10 minutes, spray malathion(0.1%) or methyl
parathion(0.05%).
 Stem borer (Pterolophia melanura and Sybra praeusta)-
Control- Apply carbofuran 3G or phorate 10G @20-25kg/ha in soil before
planting, spray carbaryl (0.1%).
 Thrips (Retithrips syriacus) leaves turn pale , roll and dry up.
 Spray Dimethoate(0.05%)
 White fly (Bemisia tubaci) It is the vector transmitting Indian cassava
moasic virus. Its control will check the spread of disease.
 Spray Dimethoate(0.05%)

19.  Spiral white fly (Aleurodicus dispersus)
 Yellowish speckels, crinkling and curling of leaves snd black
sooty mould in svere cases.
 Spray Azadirachtin or any other neem based insecticide.
 Red spider mite (Tetranychus telarius)-
Control- Dimethoate or methyl demeton (0.05%),
monocrotophos (0.03%).
 Root-knot nematode (Meloidogyne incognita or javanica or
arenaria)-
Control- Give deep summer ploughing, follows crop rotation
with resistant crops, grow resistant var.