Critical stages according to BBCH (Lancashire et al., 1991) and their deviations from the Zadok's scale (in brackets). The spacing between the stages follows calendar time for the temperate climate of Switzerland (sowing in November, harvest mid-July)
The phenological growth stages and BBCH-identification keys of cereals are:
1 A leaf is unfolded when its ligule is visible or the tip of the next leaf is visible
2 Tillering or stem elongation may occur earlier than stage 13; in this case continue
with stages 21
3 If stem elongation begins before the end of tillering continue with stage 30
Feekes scale
The Feekes scale is a system to identify the growth and development of cereal crops introduced by the Dutch agronomists Willem Feekes (1907-1979) in 1941.[1][2] This scale is more widely used in the United States[3] than other similar and more descriptive[4][5] scales such as the Zadoks scale or the BBCH scale. Like other scales of crop development, the Feekes scale is useful in planning management strategies that incorporate plant growth information for the use of pesticides and fertilizers to avoid damaging the crop and/or maximize crop yield.
Zadoks scale
The Zadoks scale is a cereal development scale proposed by the Dutch phytopathologistJan Zadoks that is widely used in cereal research and agriculture.
Knowing the stages of development of a crop is critical in many management decisions that growers make. They are represented on a scale from 10 to 92. For example, in some countries, nitrogen and herbicide applications must be completed during the tillering stage. In France, the recommendation for the first nitrogen application on wheat is 6 weeks before Z30, with the second application on Z30. Wheat growth regulators are typically applied at Z30. Disease control is most critical in the stem extension and heading stage (Z31, Z32, Z35), in particular as soon as the flag leaf is out (Z37). The crop is also more sensitive to heat or frost at some stages than others (for example, during the meiosis stage the crop is very sensitive to low temperature). Knowing the growth stage of the crop when checking for problems is essential for deciding which control measures should be followed.
Examples of typical stages
during tillering
Z10: one leaf
Z21: tillering begins
during stem extension
Z30: ear is one centimeter long in wheat
Z31: first node visible
Z32: second node visible
Z37: flag leaf
during heading
Z55: the head is 1/2 emerged.
during ripening
Z92: grains are ripe
References
^Feekes, Willem (1941). "De tarwe en haar milieu [Wheat and its environment]". Verslagen van de Technische Tarwe Commissie. (in Dutch and English). 17: 523–888.
^ a bLarge, E. C. (1 December 1954). "GROWTH STAGES IN CEREALS ILLUSTRATION OF THE FEEKES SCALE". Plant Pathology. 3 (4): 128–129. doi:10.1111/j.1365-3059.1954.tb00716.x.
^Wise K, Johnson B, Mansfield C, Krupke C. "Managing Wheat by Growth Stage" (PDF). Purdue University Extension. Retrieved 29 February 2012.
^Miller, Travis. "Growth Stages of Wheat: Identification and Understanding Improve Crop Management" (PDF). Texas Agricultural Extension Service. Archived from the original (PDF) on 25 November 2011. Retrieved 29 February 2012.
^Herbek J, Lee C (July 2009). "Section 2. Growth and Development". A Comprehensive Guide to Wheat Management in Kentucky. University of Kentucky College of Agriculture. Archived from the original on 2015-09-23. Retrieved 2016-05-14.
Lancashire, P.D.; H. Bleiholder; P. Langeluddecke; R. Stauss; T. van den Boom; E. Weber; A. Witzen-Berger (1991). "A uniform decimal code for growth stages of crops and weeds". Ann. Appl. Biol. 119 (3): 561–601. doi:10.1111/j.1744-7348.1991.tb04895.x.
Lancashire, P.D.; H. Bleiholder; P. Langeluddecke; R. Stauss; T. van den Boom; E. Weber; A. Witzen-Berger (1991). "A uniform decimal code for growth stages of crops and weeds". Ann. Appl. Biol. 119 (3): 561–601. doi:10.1111/j.1744-7348.1991.tb04895.x.
Witzenberger, A.; H. Hack; T. van den Boom (1989). "Erläuterungen zum BBCH-Dezimal-Code für die Entwicklungsstadien des Getreides - mit Abbildungen". Gesunde Pflanzen. 41: 384–388.
Further reading
J.C. Zadoks, T.T. Chang, C.F. Konzak, "A Decimal Code for the Growth Stages of Cereals", Weed Research1974 14:415-421.