Wheat growth stages
Not all plants will reach the same stage at the same time. Thus, a stage is said to be reached when around 50% of the plants reach that stage.
| Development Stage | Critical management factors | |
|---|---|---|
| 0 | Germination | Plants per sq m are being determined. Land preparation and soil pests are important. Flooding will kill young plants. Rats and birds can eat seed in the ground. |
| 1 |
Main stem leaf production Seedling Stage is the growth stage from wheat emergence until the plants begin to tiller |
Early weed control |
| 2 |
Tiller production Tillering usually starts when the plant has 3- 4 leaves. A (short growth cycle) wheat plant will typically produce 7-8 leaves on the main stem before stem elongation occurs. |
Early weed control and good nitrogen (and other nutrient) management. |
| 3 |
Stem elongation Main stem node production. The maximum potential number of florets (and therefore maximum yield potential) is now set. The tillers produced last during stem elongation will often die. The final number of productive tillers depends on the conditions. |
Good nutrient and water supply are determining yield potential. |
| 4 |
Booting By booting each plant should have 2-3 productive tillers depending on growing conditions and crop density. |
Water stress will significantly reduce yield. Ground cover should be 90% by booting. Radiation from now till anthesis will greatly affect grain number per unit area particularly in hot climates. Heavily overcast skies or prolonged mists/fogs will reduce yield. |
| 5 |
Heading The spike (also called the head or ear) is emerging from within the flag leaf. |
Water stress will significantly reduce yields. |
| 6 |
Anthesis Pollen is being released and the individual grains are being fertilized. |
Water stress is still important. |
| 7 |
Grain milk stage When the grain is squeezed, a milky solution is apparent. |
Water stress will still reduce yields. |
| 8 |
Grain dough stage When squeezed, the grain will still deform slightly, but no liquid is apparent. |
Yield is almost set, but water stress will still reduce grain size and yield. |
| 9 |
Ripening Grain is hard and firm and ready for harvest. Grain is best harvested at 14% moisture content. Wetter grain (>14% moisture content) has storage problems. |
Birds and rats may attack grain. Lodging can lead to grain spoilage. |
The following figure relates the external Zadoks stages of the plant (red) and the two internal stages, double ridges and terminal spikelet (check the vertical text). It shows when the shoot components are initiated, grow and die (green boxes) and when the yield components are formed (bars). This figure will help you decide what components you are affecting by your field practices at particular times.
| Main stage | Description | Sub-stage |
|---|---|---|
| 0 | Germination | 0.0-0.9 |
| 1 | Main stem leaf production | 1.0-1.9 |
| 2 | Tiller production | 2.0-2.9 |
| 3 | Main stem node production (stem elongation) | 3.0-3.9 |
| 4 | Booting | 4.0-4.9 |
| 5 | Heading | 5.0-5.9 |
| 6 | Anthesis | 6.0-6.9 |
| 7 | Grain milk stage | 7.0-7.9 |
| 8 | Graing dough stage | 8.0-8.9 |
| 9 | Ripening | 9.0-9.9 |
Growth stages follow Zadoks, J.C., Chang, T.T., Konzak, C.F. (1974)
Zadok's scale
The following figure will help you identify all of the Zadoks growth stages.
Images of this article taken from the book "Irrigated Wheat" and published under permission of the author