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Wheat
Wheat
An annual plant of Gramineae or
Poaceae family
Genus Triticum
Species: Triticum aestivum L.
Types: many kinds of wheat in the world today.
The two most common are common wheat, Triticum aestivum, also known as
bread wheat account for some 95% of all the consumed wheat in the world today;
and durum wheat T. turgidum ssp. durum, which is used in pasta production.
Triticum aestivum or common wheat or Bread wheat
T. turgidum & T. durum (durum wheat)
Dru na gu
Dzongkha
Bumthapkha
Sharchopkha
Lhotshamkha
Rice
Bja/ray
Thrung
Bara
Dhan
Maize
Gheyza
Ashom
Aashum
Maakai
Wheat
Ka
Ka
Bong
Gaow
Barley
Naa/Nay
nak
Phemong
Zaoun
Sweet Buckwheat
Jarey
Cha-rey
Khala
Methey Fapar
Bitter Buckwheat
Bjo
Brathma
Gungtshung/
Braima
Tithey Fapar
Finger millet
Memja
Kongpo
Kongpo
Kodo
Foxtail millet
Yangra
Ran
Yangra
Kaguni
Common millet
Chham
Cheyra
Kodo
Amaranth
Aaiam/Zim tse
maap
Moo/Lasom
Lathey
Mustard
Paeka
Yungkar
Mema
Tori
Pulses
Sem
sem
Sem chung rik
Dal
Importance of wheat in the world
• wheat, rice and corn account for 75% of the world’s grain
production and 56% of the world’s food energy.
• wheat is the second most-produced food among the
cereal crops
• Wheat grain is a staple food used to make flour for breads;
cookies, cakes, breakfast cereal, pasta, juice, noodles;
and for fermentation to make beer, alcohol, vodka or
biofuel.
• Although wheat supplies much of the world's dietary
protein and food supply it contains a protein called gluten
– coaliac diseases –wheat allergy (sensitive)
In Bhutan
• source of income, (3rd most important food crops
grown in Bhutan after rice and maize).
• uses same as mentioned above
Important growing countries
Top Ten Wheat Producers — 2005
(million metric ton)
China
96
India
72
United States
57
Russia
46
France
37
Canada
26
Australia
24
Germany
24
Pakistan
22
Turkey
21
World Total
Source:
UN Food & Agriculture Organisation (FAO)
626
In Bhutan
Source: MoA, 2006: Agriculture Statistics.
• Cropping system:
• generally grown in dry land (53.9%) as main crop
from 300m to 3000masl.
• Also grown in wet land as secondary crop after
rice (rice-wheat system, consists of 80%), maize,
potato & in rotation with Buckwheat at higher
altitude.
• significant part of the wheat crop is generally cut
as green fodder for cattle, the remaining is
harvested to supplement food consumption.
• For eg. Winter fodder up to 2500 masl & for
haymaking at elevations of 3500-4000 masl.
Origin:
11000BC in middle east; 4000 BC in asia,
europe and NAmeriaca..earliest grown
crop.
• In Bhutan: believed to have been
introduced from Tibet.
History: wild ancestor is Triticum boeticum,
fertilized with wild grass called aegilop
speltoids to give the modern wheat.
Species & Varieties
• 18 species recognized
• Most important to agriculture are:
• T. aestivum (common wheat); T.monococcum (Einkorn or
Europena wheat), T. turgidum & T. durum (durum wheat), T.
compactum (club wheat); T. dicoccum (emmer wheat - wild sp.
Wheat & closely related to durum wheat).
Genetics:
•
•
•
•
Some wheat species are diploid, with two sets of chromosomes, but many
are stable polyploids, with four sets of chromosomes (tetraploid) or six
(hexaploid).
T. aestivum: A hexaploid species that is the most widely cultivated in the
world.
T. durum: The only tetraploid form of wheat widely used today, and the
second most widely cultivated wheat.
T. monococcum (Einkorn): A diploid species with wild and cultivated
variants. Domesticated at the same time as emmer wheat, but never
reached the same importance.
T. dicoccon(Emmer): A tetraploid species, cultivated in ancient times but no
longer in widespread use.
In India
• T.aestivum or vulgare (common bread or
bread wheat) – chapati & bakery products –
grown all over India
• T.durum (durum wheat) – suji, sphagetti &
macaroni – grown in Central & South
• T.dicoccum – (emmer wheat) grown in South
India.
In Bhutan
• Many landraces or indigenous wheat varieties
replaced by Jaga ka
• All wheat varieties grown in the rice-wheat system
are Introduced spring wheat grown during winter
1. Sonalika: – early maturing variety – susceptible to
yellow (stripe) or brown (leaf) rust.
2. Bajoka -1 & 2.
2a. Bajoka-1: recommended for medium & low alt.
– matures 155-160 days
– Grows to a height of 80-85cm tall
- Yields 2.5 – 3.0 tons per hactare
- moderately resistant to yellow and brown rusts.
Bajoka-2:
• - recommended for low altitudes
• - matures 150-160 days
• - Grows to a height of 100cm tall
• - Yields 2.5 – 3.0 tons per hac
• - highly resistant to yellow and brown rusts
Dist. Features:
Sonalika and Bajoka variety
Sonalika:
Height taller than Bajoka 1&2,
Spike turns yellow, leaf blade bit bigger. In
Bajoka
Bajoka I spike remains white & straight until
maturity while spike bends at maturity for
Bajoka 2 but colour remains unchanged.
Morphology
• Two distinct parts: Root and Shoot system
• Root System: Pry or temporary root system
Secondary root system/permanent root system
- Starts with the formation of a radicle (embryonic
root) at the time of seed germination –
- Arises at the depth where the seed is planted
- absorbs nutrients for young seedling
- Growth progresses, the pry root system dies and
is replaced by more permanent Secondary Root
System (PRS)
Secondary Root System
- Arises at the point above the PRS as the
main organ of absorption of nutrients for
matured seedling/plant
- Arises near the soil surface at about 21-25
days after seed sowing (i.e. at the time of
crown root initiation stage)
-
• Shoot System –all parts above the ground
• - Stems, leaves and inflorescence
(flowering & fruiting)
• Stem & inflorescence = culm
1. Stem: round & cylindrical, hollow except
at the node (solid)
2. Leaves: 4 parts – Leaf sheath, leaf blade,
ligule, auricle
Leaf sheath: basal part of the leaf –
surrounds the culm (stem) & protects the
growing point and auxillary buds from
weather – also provide support to culm
(stem).
http://www.missouriplants.com/Grasses/Triticum_aestivum_page.html
• Leaf blade – flattened, parallel venation –
function?
• Ligule – soft membranous part at the junction of
the sheath and the blade
• Auricle – claw-like appendages projecting from
the collar of the leaf.
3. Inflorescence – flowering portion – ear or head
or spike – consist of spikelet, florets, kernel
- spikelets are systematically arranged in a zigzag
manner along a common axis (rachis)
- Wheat is a monoecious plant with perfect
flowers. It reproduces sexually as a selfpollinated crop.
• Spikelet: composed of flowers called
florets
• No. of florets in a spikelet vary from 1-5
• Florets in each spikelets are enclosed by
two glumes
• Florets: outer covering – lemma & palea
• These are hardened, modified stems that protect the floral
organs.
• The lemma is relatively larger than the palea.
• When the spikelet is closed, the lemma partly encloses the
palea.
• The pointed end on top of the lemma is called an awn.
Grain or Kernel or caryopsis - fruit formed from a single
carpel
- The
caryopsis is popularly called a grain and is the fruit
typical of the family Poaceae (or Gramineae), such as
wheat, rice, and corn.
- 3-10 mm in length, 3-5 mm in diameter
- Embryo – rich in protein called gluten- coaliac
diseases –wheat allergy (sensitive) & fats
- Bran – testa or pericarp – by-product of milling
& used as feeds.
Carbohydrates
51.8 g
Wheat germ, crude
- Dietary fiber 13.2 g
Nutritional value per 100 g
Fat
9.72 g
Energy 360 kcal 1510 kJ
Protein
23.15 g
Thiamine (Vit. B1) 1.882 mg
145%
Riboflavin (Vit. B2) 0.499 mg
33%
Niacin (Vit. B3) 6.813 mg
45%
Pantothenic acid (B5) 0.05 mg
1%
Vitamin B6 1.3 mg
100%
Folate (Vit. B9) 281 μg
70%
Calcium 39 mg
4%
Iron 6.26 mg
50%
Magnesium 239 mg
65%
Phosphorus 842 mg
120%
Potassium 892 mg
19%
Zinc 12.29 mg
123%
Percentages are relative to US
recommendations for adults.
Source: USDA Nutrient database
Manganese 13.301 mg
Carbohydrates
79 g
- Sugars 0.12 g
- Dietary fiber 1.3 g
Rice, white, long-grain,
regular, & raw
Fat
0.66 g
Protein
7.13 g
Water
11.62 g
Nutritional value per 100 g
Thiamine (Vit. B1) 0.070 mg
5%
Energy 370 kcal 1530 kJ
Riboflavin (Vit. B2) 0.049 mg
3%
Niacin (Vit. B3) 1.6 mg
11%
Pantothenic acid (B5) 1.014 mg
20%
Vitamin B6 0.164 mg
13%
Folate (Vit. B9) 8 μg
2%
Calcium 28 mg
3%
Iron 0.80 mg
6%
Magnesium 25 mg
7%
Manganese 1.088 mg
54%
Phosphorus 115 mg
16%
Potassium 115 mg
2%
Zinc 1.09 mg
11%
Percentages are relative to US
recommendations for adults.
Source: USDA Nutrient database
Growth Stages
http://weedsoft.unl.edu/documents/GrowthStagesModule/wheat/wheat.htm#
http://sanangelo.tamu.edu/agronomy/wheat/whtmang.htm (Refer)
Jointing Stage
- Is a part of the veg. stage, characterized by:
- Stem elongation
- Most tillers have formed by this stage and the secondary
root system is developing
- Plants begin to grow erect from its previous prostate growth
- the number of spikelets per spike (head size) is determined.
- The first node just above the soil surface is visible on the
main stem followed by second node as well as nodes on
tillers
- rapid spike expansion take place.
- Flag leaf becomes visible just after the second node on
main stem
At the boot stage, the
head is developed and
can be seen in the
swollen section of the
sheath of the flag leaf.
Heading and Flowering
Heading
- At this stage awns are visible and heads are
emerging through the slit of the flag leaf
sheath, with approximately 50% of heads
emerged from the flag leaf in a given area.
Flowering
- At this stage heading is complete.
- Flowering begins about 3 to 5 days after
heading, first on the main stem followed by
on the tillers.
Ripening
- This stage denotes physiological maturity.
This is followed by kernel ripening and grain
drying.
Climatic requirement
– Wide adaptability
- Prefer areas with cool, moist weather during
growing period followed by dry, warm
weather.
- Optimum temperature range for ideal
germination of seed is 20 – 25 degree
Celsius
- Can germinate in the temp range of 3.5 – 35
deg.C
- Areas with warm and damp climate are not
suited for wheat growing.
• Cloudy weather, with high humidity and low temp.
is conducive for rust attack.
• Requires about 14 -15 deg. C at the time of grain
filling & is crucial for yield
• Temp above 25 deg C tend to affect yield
Soils: SOIL
- Soil type is the most important local physical
feature affecting cropping potential and
management practices.
- Wheat grown in variety of soils
- Preferred soil types are clay loam & heavy soils
with good drainage.
- Eg. Gangetic alluvium of UP and Bihar, Indus
alluvium of Punjab and Haryana etc.
Field Preparation
- Requires a well pulverized soils for good
germination
- Field after the harvest of previous crop should
be properly ploughed and harrowed 2-3 times
followed by planking
- Pre-sowing irrigation (wetland) 7-10 days
before sowing seed is needed for proper
germination.
• Light leveling is required before sowing
seed.
• In rain-fed areas (dry land) – FP should be
done with care as conservation of moisture
is dependent on it.
• Fields are deep ploughed and done planking
• Usu. done in evening times and furrow
should be kept opened whole night to absorb
moisture from dew.
• Planking should be done in the morning
Seed and sowing
- Certified seed of right variety suitable for a
particular locality should be selected
- Seeds should be treated with Vitavax @
2.5g/kg seed to control loose smut.
Time of Sowing
- One of the important aspects in obtaining
good yields of wheat
- Varies widely over the wheat growing areas
- Depends on soil temperature, irrigation
facilities and duration of wheat varieties
- Rainfed wheat is sown in 2nd week of Oct
– beginning of November.
• Irrigated varieties sown in the beginning of
November
• Sonalika (short duration variety) is sown
sometimes in the month of Dec.
• However, when wheat is sown in the
month of Dec., there is a drastic reduction
in yield.
Method of sowing: Four methods
1. Broadcasting – uniformly broadcast and
then covered by harrowing (commonly
practiced in Bhutan)
2. Behind local plough – commonly practiced
in India – seeds are dropped by hand into
furrows that have been opened with last
plough
3. Drilling – sown by seed drill by dropping
seeds at uniform depth - Results in uniform
germination
- Seed drill may be bullock or tractor driven
4. Dibbling: – used in case supply of seeds is
limited – done with the help of a small
implement called “Dibbler”
- Not commonly used – time consuming
Management practices
Manures and Fertilizers:
- MF both play an impt roles in crop prodn –
impt in wheat cultivation
- About 5 t/ha of well decayed FYM at final
- land preparation and is mixed well
- for better yield supplement with inorganic
fertilizers @ 50:30:20 NPK kg/ha
- half of N and all of P & K should be applied
basally while the rest of the N should be topdressed at first irrigation
Seed rate: 100-130 kg/ha
Spacing: 20 - 22.5 cm between rows is
recommended & when sowing is delayed a
closer spacing of 15-18cm adopted.
Irrigation
- Adequate soil moisture is required for normal dev. of
wheat plant at all stages of growth.
- A total 5 irrigation – crown root initiation (CRI) (2025); tillering stage (40-45); jointing (booting) stage
(70-75); flowering (90-95); dough stage (110-115).
- vary depending on soil type, winter rainfall, amount
of water applied per irrigation; 3 sufficient.
• The crown root initiation (CRI) stage and heading
stage are the critical stages when plant suffers
most due to moisture stress.
• 1st Irrigation: 20-25 or 25-30 days (hilly areas like
Bhutan) after sowing i.e. at the CRI stage.
• Delay avoided – upset root growth, tillering,
heading and yield.
• 2nd Irrigation: at booting or jointing stage (70-75
days after sowing)
• 3rd Irrigation: At milk stage (90-100 days)
Harvesting
- when leaves and stems turn yellow and become
fairly dry – before it is dead ripe.
- Done manually using serrated sickle
- In villages using 2 short sticks called “Khrip or
Kreow”
Harvesting
- Usually done by cutting the
head with sickle or cutting
the entire stem
- The cut stem with ears are
bundled up and hanged to
dry
- When dry, ears are cut
from the peduncle and
beaten with stick or
crushed with feet.
Threshing: after harvest dry the crop for 3-4 day,
then stack and thresh.
- Manually using a flail (Kubji or yarjung) or power
thresher.
- made of two sticks joined by a knob, one for a
handle and the other which swirls in a clockwise
direction, threshing the crops
Storage:
- Moisture content for
safe storage is 10-12 %
Weeds – both dicot and monocot
- Major dicot weeds are: Chenopodium album,
Fumaria parviflora, Cirsium arvense, Anagallis
arvensis etc
- Monocot weeds include: Phalaris minor, Avena
fatua (wild oat), Cyperus rotundus, Cynodon
dactylon
Phalaris minor (Dwarf Canary Grass)
Cyperus rotundus or Nutgrass
Weed control
– eradicated with the help of hoe and
uprooting by hands
- Chemical weedicides are used
- Common & effective herbicide (liquid & solid)
used to kill broad-leaved weeds is 2,4 D (2,4dichlorophenoxy acetic acid).
- 700 ml/625gm is mixed with 400-600 lts of water
for spraying in an area of one hectare.
- Sprayed 32-35 days after sowing
- Spraying after 40 days not effective or not
beneficial.
• Avoid drift of spray in the adjoining crop fields,
a slight drift may spoil pulse crop (pea, lentil,
mustard)
• Monocot weeds like Phalaris minor can be
controlled by spraying Tribunil/Dosanex/
Isoproturon @ 2kg per ha in 400-600 lts of
water at 32-35 days.
Wheat Diseases
- Major diseases of wheat are rusts, loose smut,
alternaria leaf blight & powdery mildew.
- Rusts (brown & yellow) – caused by fungus sp.
Puccinia. Black rust also appears in fields that are
sown late.
Brown rust
– Puccinia recondita tritici
• Generally develop on leaves but in
severe attacks - on sheath and
stem (scattered)
• uredial pustules are bright orange
in color, which are in small clusters
or irregularly scattered.
• Spreads during warm and humid
conditions
• In severe attacks, plant mature
early, produce light and shrivelled
grains & poor dev. of roots.
• Most widespread in India
Yellow rust
• Fungus Puccinia straciformis
• Generally develop on leaves but in
severe attacks - on sheath, stem
and glumes
• uredial pustules are lemon-yellow
in color, which are in rows
• Appearance of lemon-yellow
pustules in rows is characteristic
feature
• In severe attacks, these pustules
become large patches & plant gets
completely covered
• Common in areas where temp
gets considerably low during the
wheat growing season
• Problem of the hills, foot-hills.
Black rust:
Puccinia graminis tritici
- Uredial pustules occur on
stem, sheath, leaves and
earheads
- stem severely affected.
- Formation of dark, black,
elongated telial pustules
- Spreads during warm and
humid conditions
Rust control measures
- Avoid growing single variety in entire field – adopt
2-3 varieties
- Avoid late sowing as late sown crop is susceptible
- Avoid excess use of nitrogenous fertilizers as high
dose of nitrogen favours rust formation
- Spraying Zineb or Dithane M-45 with Sandovit
- Spraying is recommended if good crop is
threatened
- 1st spray when pustules are seen @ 375 lts solution
per ha
- 2nd spray after 10 days @ 750 lts solution per ha
- 3rd & 4th spray at the interval of 14 days @ 1000 and
1250 lts soln per ha, respectively
Other diseases:
• Loose smut – smut fungus,
Ustilago nuda tritici
• Distinguishable after heading from
healthy plants
• Production of black powder in
place of grains in the ears -every
ear is converted into black
powder
• Is a mass of olive-green
microscopic spores – blown,
germinate on the female organ,
stigma leading to infection of
developing seed.
Control:
- resistant variety, Vitavax
- uproot the infected plant
(cover the black spores)
and burn it.
Alternaria leaf blight
- Fungus, Alternaria triticina
- Lowermost leaves show
the sign of infection first
and spread to upper
leaves
- Small, oval, discoloured
lesions, irregularly
scattered spots on leaves
– become dark brown and
irregular - Death of entire
leaf
Control
– Vitavax and spraying Zineb
or Dithane M-45
Powdery Mildew:
- Fungus, Erysiphe graminis
tritici
- Characterized by formation
of white, powdery growth of
the fungus (spores) on the
upper surfaces of leaves
- Leaf sheaths, stems and
earheads may also be
affected when severe
Control
– resistant variety
– burn crop residues after
harvest