1- Closely examine the heads (also called the spike) of primary tillers at multiple locations in the field for the presence of anthers – often seen as a yellowish (or other color) part of the flower hanging from the spikelet; 2- If no anthers are seen, then your wheat may still be at the heading growth stage, Feekes 10.5; 3- If the first few anthers are seen hanging from florets/spikelets in the central portion of the spike, your wheat is at Feekes 10.5.1 - early flowering or early anthesis; 4- If anthers are seen hanging from florets/spikelets in the central and top portions of the spike, your wheat is at Feekes 10.5.2 - mid-flowering or mid-anthesis; 5- If anthers are seen hanging from florets/spikelets along the entire length of the spike, your wheat is at Feekes 10.5.3 - late-flowering or late-anthesis; Note: When trying to identify these growth stages, based your assessment on the presence of fresh (brightly colored) anthers, since dried, discolored, and spent anthers may remain hanging from the spike well after Feekes 10.5.3 and well into grain filling stages of development.
Independent and combined drought and heat stress negatively affect wheat yield and physiology.
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.
The present study was aimed to quantify effects of Drought [D], heat [H] and combined heat and drought [HD] during reproductive stage on wheat yield and to identify physio-biochemical traits which were strongly associated with improved yield and tolerance of wheat under stressful conditions.
One hundred and eight elite diverse wheat genotypes were exposed to [H], [D] and [HD] treatments from heading till maturity.The final number of productive tillers depends on the conditions. Heavily overcast skies or prolonged mists/fogs will reduce yield.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).Main stages 1 and 2 describe leaf and tiller production that actually occur in parallel, not in sequence.Similarly there is some overlap of main stages 2 and 3.As with earlier stages, the number following the decimal point denotes the degree to which the process is complete.So Zadoks 5.1 is when the tip of the average spike in the field is 0.1 or 10% emerged (ear peep) while Z5.9 is when 0.9 or 90% of the average spike is above the flag leaf collar.This overlap means that your crop can have two or even three Zadoks stages at the one time.The drawings illustrate germination and 3 stages during vegetative growth with their Zadoks decimal codes (identified as Z in this booklet but elsewhere often abbreviated to DC for Decimal Code).Depending on the weather and the variety, flowering usually occurs about 3-5 days after full head emergence (Feekes 10.5) – earlier under warmer conditions and delayed by up to 5 or more days after heading under cooler conditions.Flowering is marked by the extrusion of anthers from the spikelets; the reason for which this process is also referred to as anthesis. The identification of this growth stage is very important for the management of Fusarium head blight (head scab) with fungicides.