AGR 301 :: Lecture 02 ::WHEAT TRITICUM SP

Origin

  • De Candolle believed – Valley of Euphrates and Tigris
  • But Vavilov
    • Origin of Durum wheat probably Abyssinia
    • Soft wheat groups – In the region of Western Pakistan, SW Afghanistan, and S parts of mountainous Babshara

Importance

  • World’s number one cereal in area
  • Cultivation of wheat is as old as civilization
  • It is the first mentioned crop in Bible
  • Used for bread, cakes, bakeries, also manufacture of dextrose, alcohol etc
  • A nutritious food of all

Classification of wheat

  • Genus Tricum can be classified into 3 groups
    • Diploids = 7 pairs of chromosomes
    • Tetraploids = 14 pairs
    • Hexaploids = 21 pairs

Commonly cultivated wheat sp

  • There are 7 in the world,  only 4 is important in India,  they are:
    • Common wheat ( T vulgare / aestivum)
      • Bread wheat
      • Most suited for chapati and bakery
      • Cultivated throughout India
      • Common wheat may be sub-divided
        • Hard red winter wheat – commercial class
        • Hard red spring – where winter is too severe, high protein and excellent bread making characteristics
        • Soft red winter – grown in humid conditions, grains are soft, low protein, flour more suitable for cakes, cookies
        • White wheat – mainly for pasty purpose

    • Duram (T durum)
      • Macroni wheat
      • Best suited for noodles, vermicelli
      • Spring habit
      • Cultivated in Central & Southern India

    • Emmer wheat (T dicoccum)
    • Winter / spring wheat
      • Wheat suitable for TN
      • Preferred for granular preparation
      • Gujarat, Maharastra, AP & TN

    • Shot wheat (T sphaerococcum)
      • Indian dwarf wheat
      • Practically gone out of cultivation due to low productivity
      • Small extent N. India and W Pak for local consumption
  • Varieties
    • Sonak – to replace Sonalika
    • HD 2285
    • PBW 343, HD 2687, WH 542, UP 2336, Raj 3077, CPAN 3004, PDW 215
    • Many more like
      • Varieties for irrigated late sown
      • Varieties for salt affected areas etc
  • Adaptation and distribution
    • Widely cultivated cereal
    • 47ºS to 57ºN latitude
    • Cultivated in wide range of soils but
    • Well suited to fertile well drained silt and clay loam soils
    • Poorly suited to sandy or poorly drained soils
  • Climate
    • Wheat has hardening ability after germination
    • It can germinate at temp just above 4ºC
    • After germination it can withstand freezing temperatures by-
      • Spring wheat - as low as  (-9.4ºC)
      • Winter wheat – as low as (-31.6ºC)
    • Normal process starts above 5ºC under the presence of adequate sunlight
    • During the process of hardening there is gradual increase in the dry matter, sugars, amide nitrogen, and amino nitrogen in the tissues
    • As a result there is greater tolerance to freezing of proteins
    • Hardened plants have lower moisture in the leaves and
    • Water is held more tightly within the cells
  • Response to photo period and growth
    • It is long day plant
    • Long day hastens the flowering
    • Short day increase the vegetative period
    • But no more varieties after the release of photo-insensitive
  • Temperature and growth
    • Wheat can be exposed to low temp during vegetative and high temp and long days during reproductive phases
    • Optimum is 20-22ºC
      • Optimum for vegetative – 16-22 º C
      • Leaves are largest at 22 º C
    • Temp above 22 ºC decreases the plant height, root length and tiller number
    • Heading is accelerated as temp rose from 22 to 34 ºC but retarded above 34 ºC
    • At grain development 25 ºC  for 4- 5 weeks is optimum
      • Temp above 25 ºC reduce the grain weight

Growth stages in wheat in North India

  • Vegetative
    • Germination : 5-7 days
    • CRI : 20-25 DAS
    • Tillering: from 15 days at 4-5 days until 45 DAS
    • Jointing: Peak plant growth 45-60 DAS
      • Internode elongation period
  • Reproductive
    • Boot leaf 70-75 DAS
    • Flowering : 85-90 DAS
    • Milking: 100-105DAS
    • Dough: 105-110
    • Maturity: 115 – 120

  • Coordinating Research Zones
    • There are 6 zones in India for wheat improvement and coordination
    • Northern Hills Zone
    • North Western Plans Zone
    • North Eastern Plains Zone
    • Central Zone
    • Peninsular Zone
    • Southern Hills Zone

Different growth stages of wheat
 
                


Wheat cultivation practices

  • Season
    • Time of sowing decides yield potential in wheat
    • Irrigated long duration varieties (135-140d)
      • Nov 10-30th
    • Short duration varieties (120-125)may be sown up to Dec 15
    • Later than Dec 15th there is drastic reduction in yield
    • Zone wise there is slight variation
  • Field preparation
    • Usually after harvest of Kharif crops
    • Field is prepared by disking once and harrowing
    • Moderate to fine tilth is suitable
    • Zero tillage also possible
      • After rice dibbling in lines may be an option

fdforsow

  • Methods of sowing
    • Broad casting
    • Zero / No-tillage sowing
    • Behind the plough
    • Drilling
    • Dibbling
    • FIRB – Furrow irrigated raised bed system

  • Seed rate
    • Normal recommendation 100-125 kg /ha
    • Increase seed rate by 25% when
      • Under late sown
      • When the soil moisture is less
    • Broadcast requires higher seed rate – 150 kg
    • For dibbling 25-30kg is sufficient
  • Spacing
    • Varies with varieties
    • Tillering variety requires wider spacing
    • Irrigated wheat spaced 22.5 cm  and 8-18 cm between plants
    • Rainfed wheat – 25-30 cm x 5-6cm
    • When late sown closer spacing 15-16cm
  • Mineral Nutrition
    • Nitrogen
      • Critical leaf N conc is 2.5%
      • Poor tillering and small ear heads are deficiency
      • Indian soils lack N
      • General recommendation
        • For irrigated crop -s 120-150 kg
        • Rainfed  - 40-60kg
      • Irrigated 2-3 equal splits
        • Heavy soils 2 splits
        • Light soils three
      • Basal, 1st irrigation and 2nd irrigation are time
      • In rainfed crop if moisture availability is sufficient
        • Additional dose may be – 40kg/ha
      • All the nitrogenous may be used
      • For calcarious and strongly alkaline soils
        • Ammonium sulphate is better than Urea

    • Phosphorous
      • It is also critical nutrient particularly for dwarf
      • If adequate P fertilization is done for
        • Maize-wheat
        • Sorghum – wheat
        • Rice-wheat
      • P may be reduced or avoided
      • But most of soils are responding
      • May be 0.1% dry leaf P conc be maintained
      • 60kg P2O5 at planting is good
      • Source wise water soluble is preferred
      • Rock phosphate efficiency much lower
      • For acid soils
        • Use of rock phosphate with pyrites may be useful
      • When the water soluble (SSP / DAP) when placed near the root zone is more efficient than broadcasting
      • All P as basal
    • Potassium
      • There is response to applied K
      • In general Indo-Gangetic alluvium is rich in K and not recommended with K
      • General recommendation is 40-60kg /ha
      • May be basal or split along with 1st irrigation
    • Micro-nutrients
      • Zn, Fe, Cu, Mn and B are reported as deficient in certain soils and conditions
      • Zn is widely reported
        • <10ppm in leaves is acute deficiency
        • Higher P is interfering with Zn
        • Generally 25 kg Zn SO4 /ha
        • Foliar spray with 0.5%
          • 5kg ZnSO4 along with 2.5kg slaked lime is dissolved in 1000 lit to spray 1 ha
    • INM
      • Green manure / FYM applied to Kharif  crop
      • A pulse crop before wheat
      • Biofertlizers along the seeds and soil

  • Irrigation
    • Highly responds to irrigation
    • 4-6 irrigations are essential
    • 40-50% depletion of ASM
    • Appropriate IW :CPE ratio for wheat 0.7-0.9
    • On clay loam up to 80% depletion
    • Critical phases for irrigation are
      • CRI – 20-25 DAS)
      • Second most critical stage – Flowering
      • Third important stage – jointing and milk stages
  • For varying number irrigations

No of irrigations

Stages

1

CRI

2

CRI + LJ

3

CRI + B + M

4

CRI + LT + F + M

5

CRI + LT + LJ + F + M

6

CRI + LT + LJ + F + M + D

CRI – Crown root initiation; LT – Late tillering; LJ – late jointing; F- Flowering; M- milking; D – Dough stages

  • Weed control
    • Deadly competitor
    • Should be controlled at the early
    • Better filed maintenance to previous crop
    • Problematic mono-cot weeds are
      • Phalaris minor – (Canary grass)
      • Avena fatua (Wild oat)
      • Polypogan monspliensis
    • Hand weeding is recommended
      • Before 20-25DAS
      • Second weeding 2 weeks later
    • Use of herbicides becomes handy
      • Dicots can be controlled by 2,4 D (EE) 0.3-0.4 kg /ha at 35DAS
      • Monocots can be controlled by
        • Isoproturon 1-1.5kg /ha  or
        • Methabenzthiazuron 1.5 kg  or
        • Metoxuron 1.5 kg /ha on 30-35 DAS
      • Pre-emergence application of Pendimethalin or Isoproturon  is broad spectrum control
  • Harvesting and threshing
    • Yellow and dry straw is visual indicator
    • Shredding, breaking of spikes are over ripe
    • Most suitable stage is grain moisture of 20-25%
    • Combine harvester is ideal
    • Usually manually harvested or by reapers is dried for 3-4 days on threshing floor and threshed

Woman harvesting wheat

  • Wheat based cropping systems
    • Normally wheat is cultivated after Kharif crops under double crop sequence
    • Kharif crops may be
      • Rice, maize, sorghum, millet, mungbean, urdbean, cowpea, pigeonpea, cotton etc.,
    • A third crop of any catch crop is raised in certain pockets
    • In UP wheat is alternated with sugarcane

Multiple choice questions

  1. Bread wheat is ___________
    a. Secale cereale                  b. Hordeum vulgare                c. Triticum aestivum
  2. According to Vavilov the origin of Durum wheat is ________
    a. Abyssinia                         b. Asia                         c. Africa
  3. Permanent adventitious roots of wheat is called __________
    a. Primary roots                    b. Secondary roots     c. Clonal roots
  4. Common wheat is ________
    a. Triticum durum                  b. Triticum dicoccum        c.     Triticum aestivum
  5. Duram wheat is ________
    a. Triticum durum               b. Triticum dicoccum        c. Triticum aestivum
  6. Emmer wheat is ________
    a. Triticum durum      b. Triticum dicoccum                 c.     Triticum aestivum
  7. Wheat is a _________ plant
    a. Short day                          b. long day                 c. day neutral
  8. Duration of CRI stage in wheat is ________ DAS
    a. 45-60                     b. 20-25                       c. 30-45
  9. Duration of boot leaf stage in wheat is ________ DAS
    a. 45-60                     b. 70-75                       c. 30-45
  10. Duration of flowering stage in wheat is ________ DAS
    a. 85-90                     b. 70-75                       c. 100-105
  11. Duration of milking stage in wheat is ________ DAS
    a. 85-90                     b. 70-75                       c. 100-105
  12. Duration of dough stage in wheat is ________ DAS
    a. 105-110                 b. 115-120                   c. 100-105
  13. Duration of maturity stage in wheat is ________ DAS
    a. 105-110                 b. 115-120                   c. 100-105
  14. Normal recommendation of seed rate for wheat is ________ kg/ha
    a. 75-90                     b. 90-100                     c. 100-125
  15. The recommended seed rate for wheat under dibbling method is ________ kg/ha
    a. 25-30                     b. 30-45                       c. 45-60
  16. General recommendation of inorganic fertilizers for wheat is ________ kg/ha
  • 120-150 : 60 : 40-60         b. 130-145 : 65 : 60     c. 145-160 : 65 : 65
  • Spacing for irrigated wheat is ____________
  • 22.5 x 8-18 cm                  b. 25-30  x 5-6cm       c. 25 x 15 cm
  • Spacing for rainfed wheat is ____________
  • 22.5 x 8-18 cm                  b. 25-30  x 5-6cm       c. 25 x 15 cm
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