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:
Growth stage
Code
Description
0: Germination
00
Dry seed (caryopsis)
01
Beginning of seed imbibition
03
Seed imbibition complete
05
Radicle emerged from caryopsis
06
Radicle elongated, root hairs and/or side roots visible
End of tillering. Maximum no. of tillers detectable
3: Stem elongation
30
Beginning of stem elongation: pseudostem and tillers erect, first internode begins to elongate, top of inflorescence at least 1 cm above tillering node
31
First node at least 1 cm above tillering node
32
Node 2 at least 2 cm above node 1
33
Node 3 at least 2 cm above node 2
3 .
Stages continuous till ...
37
Flag leaf just visible, still rolled
39
Flag leaf stage: flag leaf fully unrolled, ligule just visible
4: Booting
41
Early boot stage: flag leaf sheath extending
43
Mid boot stage: flag leaf sheath just visibly swollen
45
Late boot stage: flag leaf sheath swollen
47
Flag leaf sheath opening
49
First awns visible (in awned forms only)
5: Inflorescence emergence, heading
51
Beginning of heading: tip of inflorescence emerged from sheath, first spikelet just visible
52
20% of inflorescence emerged
53
30% of inflorescence emerged
54
40% of inflorescence emerged
55
Middle of heading: half of inflorescence emerged
56
60% of inflorescence emerged
57
70% of inflorescence emerged
58
80% of inflorescence emerged
59
End of heading: inflorescence fully emerged
6: Flowering, anthesis
61
Beginning of flowering: first anthers visible
65
Full flowering: 50% of anthers mature
69
End of flowering: all spikelets have completed flowering but some dehydrated anthers may remain
7: Development of fruit
71
Watery ripe: first grains have reached half their final size
73
Early milk
75
Medium milk: grain content milky, grains reached final size,
still green
77
Late milk
8: Ripening
83
Early dough
85
Soft dough: grain content soft but dry. Fingernail impression not held
87
Hard dough: grain content solid. Fingernail impression held
89
Fully ripe: grain hard, difficult to divide with thumbnail
9: Senescence
92
Over-ripe: grain very hard, cannot be dented by thumbnail
93
Grains loosening in day-time
97
Plant dead and collapsing
99
Harvested product
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.
One shoot (number of leaves can be added), first leaf through coleoptile.
2
Beginning of tillering; main shoot and one tiller.
3
Tillers formed; leaves often twisted spirally. Main shoot and six tillers. In some varieties of winter wheat, plant may be "creeping," or prostrate.
4
Beginning of the erection of the pseudo-stem; leaf sheaths beginning to lengthen.
5
Pseudo-stem (formed by sheaths of leaves) strongly erected.
Stem Extension
6
First node of stem visible at base of shoot.
7
Second node of stem formed; next-to-last leaf just visible.
8
Flag leaf (last leaf) visible but still rolled up; ear beginning to swell.
9
Ligule of flag leaf just visible.
10
Sheath of flag leaf completely grown out; ear swollen but not yet visible.
Heading
10.1
First spikelet of head just visible.
10.2
One-quarter of heading process completed.
10.3
Half of heading process completed.
10.4
Three-quarters of heading process completed.
10.5
All heads out of sheath.
Flowering
10.51
Beginning of flowering.
10.52
Flowering complete to top of head.
10.53
Flowering completed at base of head.
10.54
Flowering completed; kernel watery ripe.
Ripening
11.1
Milky ripe.
11.2
Mealy ripe; contents of kernel soft but dry. Soft dough.
11.3
Kernel hard (difficult to divide with thumbnail).
11.4
Ripe for cutting. Straw dead.
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
Comparison of growth stage scales
Zadok Scale
Feekes Scale
Haun Scale
Description
Germination
00
Dry seed
01
Start of imbibition
03
Imbibition complete
05
Radicle emerged from seed
07
Coleoptile emerged from seed
09
0.0
Leaf just at coleoptile tip
Seedling growth
10
1
First leaf through coleoptile
11
1.+
First leaf unfolded
12
1.+
2 leaves unfolded
13
2.+
3 leaves unfolded
14
3.+
4 leaves unfolded
15
4.+
5 leaves unfolded
16
5.+
6 leaves unfolded
17
6.+
7 leaves unfolded
18
7.+
8 leaves unfolded
19
9 or more leaves unfolded
Tillering
20
Main shoot only
21
2
Main shoot and 1 tiller
22
Main shoot and 2 tillers
23
Main shoot and 3 tillers
24
Main shoot and 4 tillers
25
Main shoot and 5 tillers
26
3
Main shoot and 6 tillers
27
Main shoot and 7 tillers
28
Main shoot and 8 tillers
29
Main shoot and 9 or more tillers
Stem Elongation
30
4-5
Pseudo stem erection
31
6
1st node detectable
32
7
2nd node detectable
33
3rd node detectable
34
4th node detectable
35
5th node detectable
36
6th node detectable
37
8
Flag leaf just visible
39
9
Flag leaf ligule/collar just visible
Booting
40
-
41
8-9
Flag leaf sheath extending
45
10
9.2
Boots just swollen
47
Flag leaf sheath opening
49
10.1
First awns visible
Inflorescence emergence
50
10.1
10.2
First spikelet of inflorescence visible
53
10.2
1/4 of inflorescence emerged
55
10.3
10.5
1/2 of inflorescence emerged
57
10.4
10.7
3/4 of inflorescence emerged
59
10.5
11.0
Emergence of inflorescence completed
Anthesis
60
10.51
11.4
Beginning on anthesis
65
11.5
Anthesis half-way
69
11.6
Anthesis completed
Milk development
70
-
71
10.54
12.1
Kernel watery ripe
73
13.0
Early milk
75
11.1
Medium milk
77
Late milk
Dough development
80
-
83
14.0
Early dough
85
11.2
Soft dough
87
15.0
Hard dough
Ripening
90
-
91
11.3
Kernel hard (difficult to divide with thumbnail)
92
11.4
16.0
Kernel hard (no longer dented with thumbnail)
93
Kernel loosening in daytime
94
Overripe, straw dead and collapsing
95
Seed dormant
96
Viable seed giving 50% germination
97
Seed not dormant
98
Secondary dormancy induced
99
Secondary dormancy lost
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.
^ abLarge, 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.
^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.
