Morphology and Growth

Morphology Growth


  • The genus Triticum embraces 22 species. Only two of them Triticum aestivum (soft wheat) Triticum durum (hard or durum wheat, macaroni wheat) are cultivated. Of all other wheat species only Triticum diccocum (Emmer wheat - Tetraploid 2n=28) is occasionally grown in wheat fields.
  • The grain of durum wheat contains more protein up to 18 - 20 % but its gluten is not porous and not elastic, that is why bread made out of durum wheat is of low porosity. It is extremely good for manufacturing macroni and confectionaries
  • Habit : Erect, annual which grows from 30 to 120 cm.
  • Roots : Mostly adventitious and fibrous.
  • Stem : Cylindrical with distinct nodes and internodes. Nodes are swollen and internodes are hollow. Usually there are six internodes and the sixth is the spike bearing one.
  • Leaves : Simple, alternate in distichous alternate leaves arranged to right and left side of the stem on one plane arrangement, long, linear lamina with leaf sheath covering the internodes, ligule membranous, auricles prominent, claw shaped and clasp the stem. The two halves of the lamina are unequal and show a tendency to twist.
  • Inflorescence : It is called as head, spikes or ear. Often 15 - 20 spike lets are borne on rachis in a zigzag shape. The spike lets have two glumes, which may end as an awn (lemma).
  • Structure of spike let: The wheat inflorescence is a terminal distichous spike (ear), spike lets are sessile and borne singly at the nodes on alternate sides of the zigzag rachis. Each spike let consists of two to five florets attached alternately on opposite sides of a short central axis called rachilla and is covered by two sterile or empty glumes. Lemma broad with an acute tip or awn, palea thin. The lower lemmas are fertile while the top one or two are sterile. Lodicules two, stamens three with thin filaments and large anthers superior ovary, styles two, single ovule, bifid feathery stigma.
  • Structure of the grain: The fused pericarp and testa surrounds both the endosperm and the embryo with the scutellum in direct contact with the surface of the endosperm. The axis consists of the primary root, which is enclosed by the coleorhiza, and the plumule with the protecting sheath of the coleoptile enclosing the primordia of two or three foliage leaves and the shoot apex. The part of the axis between the point of attachment of the scutellum and the plumule is called the mesocoty1 which is the internode between the scutellum representing the cotyledon and the coleoptile representing the next leaf.
  • Fruit (grain) : Dry one seeded indehiscent known as caryopsis having more or less oval shape. The apex of the grain has tufts of hairs called bush. The other side has a longitudinal grove or a furrow often called the crease. The either sides of the furrow are called cheeks. The embryo is situated at the base on the dorsal side of the grains.


Growth stages of wheat plant

    1. Pre establishment stage

    a. Pre emergence: Sprouting of seeds by giving rise to seminal roots and coleoptiles.
    b. Emergence: Appearance of coleoptiles from germinating seeds above the soil surface

    2. Vegetative stage

    a. Seedling: The young plants establish larger root systems in this stage. The stage may be further differentiated as one leaf, two leaf, three leaf and four leaf stage.
    b. Crown root stage: This coincides with three or four leaf stage in which the crown roots appear.
    c. Tillering: Plants develop crown and branch out into tillers from their base at soil surface.
    d. Jointing: This is the stage at which the plants start elongating when the nodes start developing above the crown node.

    3. Reproductive stage

    a. Booting: In this stage the uppermost leaf swells out into flag holding the spike into it.
    b. Heading: The spikes start emerging out from the leaf sheath at this stage.
    c. Flowering: Anthesis of florets and fertilization of ovaries takes place at this stage.

    4. Post anthesis stage

    a. Filling: The ovaries after fertilization start elongating in to seeds and pass through milk, soft dough and hard dough stages.
    b. Maturity : Colour of the glumes changes and kernels become fairly hard at this stage.