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Cereal growth staging scales
Cereal growth staging scales
Cereal growth staging scales
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Cereal growth staging scales attempt to objectively measure the growth of cereals.

BBCH-scale (cereals)

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In agronomy, the BBCH-scale for cereals describes the phenological development of cereals using the BBCH-scale.

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
07 Coleoptile emerged from caryopsis
09 Emergence: coleoptile penetrates soil surface (cracking stage)
1: Leaf development1, 2 10 First leaf through coleoptile
11 First leaf unfolded
12 2 leaves unfolded
13 3 leaves unfolded
1 . Stages continuous till ...
19 9 or more leaves unfolded
2: Tillering3 20 No tillers
21 Beginning of tillering: first tiller detectable
22 2 tillers detectable
23 3 tillers detectable
2 . Stages continuous till ...
29 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

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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.

Cereal growth stages using the Feekes scale[2]
Stage Description
Tillering
1 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

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The Zadoks scale is a cereal development scale proposed by the Dutch phytopathologist Jan 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

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Cereal growth staging scales

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Cereal growth staging scales are standardized systems designed to objectively describe the developmental phases of cereal crops, including , , oats, and , from to maturity. These scales facilitate precise timing for agricultural practices such as application, , and harvest decisions by replacing vague terms like "early growth" with numerical codes based on observable morphological changes. The most widely used scales include the Feekes scale, developed in the 1940s for and other cereals, which divides growth into 11 main stages (1.0 to 11.0) with subdivisions for finer detail, such as tillering (stage 2.0–3.0) and heading (stage 10.0–10.5). Another prominent system is the Zadoks scale, also known as the code, introduced in 1974 and structured around 10 principal stages (0–9), each subdivided into 10 secondary stages (00–99) to track events like leaf development (stage 1), stem elongation (stage 3), and (stage 9). The BBCH scale, a harmonized adapted for cereals, builds on the Zadoks framework with similar 10 principal stages (GS 0–9) but emphasizes uniform coding for global use in research, advisory services, and agrochemical labeling, covering phases from (GS 0) to (GS 9). These scales are essential for crop management because they account for environmental variations affecting development rates, allowing farmers and researchers to benchmark progress against expected timelines and optimize inputs like at key points, such as jointing (Feekes 6.0 or Zadoks 3) or flag leaf emergence (Feekes 8.0 or BBCH 39). In practice, staging involves examining representative plants—often 50% of tillers in a field sample—to identify the growth stage, ensuring decisions align with the crop's physiological needs across diverse growing conditions.

Overview

Definition and Scope

Cereal growth staging scales are standardized systems designed to objectively describe the phenological development of , tracking progression from through to maturity in a consistent manner. These scales categorize the plant's life cycle into defined phases based on observable morphological and physiological changes, enabling precise communication about crop status. The scope of cereal growth staging scales is focused on major temperate cereal species, including , , oats, , and , which share similar developmental patterns. Cereal grains such as and , which have different growth habits, fall outside this scope and utilize distinct staging systems tailored to their unique physiologies. At their core, these scales employ or numbered coding systems to denote principal and secondary stages of development, such as tillering, heading, and , allowing for detailed yet universal notation of growth progress. The development of such scales addressed the longstanding need for uniformity in description across diverse regions and languages, promoting reliable international exchange of agronomic and findings.

Purpose and Benefits

Growth staging scales for cereals serve primarily to standardize the description of development, enabling clear communication among farmers, , agronomists, and industry stakeholders across different regions and languages. By providing a common reference framework, these scales replace vague terms like "tillering" with precise codes, such as Zadoks stage 12 for the two-leaf stage, facilitating accurate exchange of information on status. This is essential for international and advisory services, as recognized by bodies like the Australian Weeds Committee for its adoption in farming publications and labeling. A key purpose of these scales is to guide the timing of critical agronomic practices, including fertilization, , and , which are most effective when aligned with specific developmental phases rather than calendar dates. For instance, applying at Feekes growth stage 5 or Zadoks stage 31 maximizes uptake and minimizes losses, while herbicide applications are optimized to avoid during sensitive periods like stem elongation. This precision supports , as pesticide labels often specify allowable application windows based on growth stages, such as Zadoks 30-39 for certain fungicides to control diseases like head blight. The benefits of using growth staging scales extend to enhanced crop management precision, leading to improved yields and resource efficiency in cereal production. By enabling timely interventions, these scales optimize inputs like nitrogen and water, reducing waste and environmental impact while boosting economic returns—for example, proper staging can increase grain protein content and decrease screenings in wheat. In research and field trials, they ensure data comparability across sites and seasons, supporting the development of predictive models for crop growth and yield forecasting. Overall, this leads to more profitable farming decisions, such as harvest timing to minimize losses from lodging or weather, as demonstrated in high-yield potential fields where stage-based management enhances performance.

Historical Development

Early Descriptive Systems

In the 19th and early 20th centuries, cereal growth was primarily described using informal, qualitative terms derived from observational farming practices in European agricultural literature, such as "shooting" for stem elongation and "milking stage" for the period when developing grains exude a milky substance upon pressure. These descriptive approaches, often documented in regional agronomic texts and farmer handbooks, allowed local cultivators to track development for timing harvests, pest interventions, and without numerical precision. For instance, terms like "tillering" or "ear emergence" captured vegetative and reproductive phases based on visible morphological changes, reflecting practical needs in monoculture systems dominant across . However, these early systems suffered from significant limitations, including high subjectivity in interpretation, as observers relied on personal judgment without standardized criteria, leading to variable assessments even within the same region. Language barriers further exacerbated inconsistencies, with translations of terms like "" or "dough stage" varying across French, German, and English texts, hindering reliable communication in international agronomic exchanges. The lack of precision also contributed to challenges in , such as evaluating or impacts across trials, as growth phases could not be uniformly quantified for . Key influences on these descriptive methods included adaptations of botanical classifications originally developed by in the 18th century, which emphasized morphological traits and phenological timing for and were extended by early agronomists to track in field contexts. The transition from these informal systems was driven by post-World War I increases in global seed trade and the imperative for uniform variety testing to ensure quality and comparability in international markets, as fragmented descriptions impeded standardized evaluations of breeding lines and yields. These early descriptive approaches provided a conceptual foundation for later standardized systems, such as the Feekes scale introduced in 1941.

Emergence of Standardized Scales

The development of standardized cereal growth staging scales began during and accelerated in the post-war era amid rapid advancements in mechanized farming practices and growing emphasis on international collaboration in agricultural research. These scales provided a numerical, objective framework to describe development, enabling precise timing for operations such as planting, fertilization, and harvesting across diverse regions and mechanized systems. The need for uniformity arose from inconsistencies in earlier descriptive methods, which hindered comparative studies and practical applications in an era of expanding global trade and scientific exchange. A pivotal milestone came in 1941 with the introduction of the Feekes scale by Dutch agronomist Willem Feekes, specifically designed for cultivation in the ; it was originally published in Dutch and later translated and illustrated in English by E.C. Large in 1954. This system assigned numerical values to key growth phases, from to , offering the first structured approach to track development reproducibly. Building on this foundation, the 1974 Zadoks scale, developed by J.C. Zadoks, T.T. Chang, and C.F. Konzak from institutions in the and the , represented a significant extension, introducing a decimal coding system adaptable to multiple beyond , such as and oats. It emphasized clarity and universality to support cross-border research. The emergence of these scales was largely driven by the requirements of programs, which demanded consistent staging to evaluate varietal performance under controlled trials, and the , which relied on accurate growth phase identification for optimal application of herbicides, fungicides, and other interventions. However, early adoption encountered hurdles, including variations in stage interpretation due to environmental factors like and conditions, which could alter developmental timing and lead to discrepancies in field assessments. These standardized systems ultimately paved the way for further harmonization efforts, such as the BBCH scale, by establishing a precedent for numerical precision in cereal .

Zadoks Scale

Origins and Methodology

The Zadoks scale, also known as the decimal code, is a standardized system for describing the growth stages of crops, primarily developed for but applicable to other cereals like , oats, and . It was introduced in 1974 by Dutch phytopathologist Jan C. Zadoks, along with T.T. Chang and C.F. Konzak, in the publication "A decimal code for the growth stages of cereals" published in Weed Research. The scale emerged from efforts to create a precise, numerical framework for phenological development to support agricultural research, pest management, and crop protection, replacing qualitative descriptions with observable morphological criteria. The methodology uses a two-digit decimal coding system ranging from 00 to 99, where the first digit represents one of 10 principal growth stages (0–9) and the second digit indicates the progress within that stage (0–9). This allows for detailed tracking of development by focusing on countable features, such as the number of leaves, tillers, or nodes, primarily on the main shoot or stem. The scale emphasizes objectivity through visible or palpable changes, accounting for variability due to environmental factors like and variety, and is assessed on representative in the field. The system covers the full crop lifecycle, from to , with a hierarchical structure that permits concurrent notation of multiple processes (e.g., tillering during development). It has been widely adopted internationally for agronomic decisions, such as timing or applications, and forms the basis for later scales like BBCH.

Key Growth Stages

The Zadoks scale divides cereal development into 10 principal growth stages (0–9), each with up to 10 secondary stages (00–99), enabling precise phenological assessment across species like and through observable traits on the main stem. This facilitates standardized communication in farming, research, and chemical labeling. Stage 0 (00–09) covers , starting with the dry (00) and progressing through (01), emergence (03), emergence from soil (09). This phase, lasting 5–10 days depending on and (optimal around 10–15°C for ), marks the onset of establishment. Leaf development (stages 10–19) begins at 10 with the first true leaf emerging through the , advancing to 19 with nine or more leaves fully unfolded ( visible). Leaves are counted on the main shoot; for example, stage 13 indicates three leaves, typically reached 2–3 weeks after in spring under favorable conditions. Tillering (20–29) starts at 20 (no tillers) and reaches 29 with the maximum number of tillers formed, often 4–6 in . Tillers, basal side shoots, emerge from sheaths and contribute to yield; this phase may overlap with development, beginning around stage 12–13. Stem elongation (30–39) initiates at 30 with the beginning of internode growth (pseudostem erect), progressing through node visibility (31–37) to 39 when the is visible and the sheath is extended. This rapid growth phase, often doubling height in 2–4 weeks, is key for assessing stem strength and needs. Booting (40–49) involves the flag leaf sheath swelling (41–45) as the young is enclosed, up to 49 when the is just visible. This pre-heading stage protects the developing and is influenced by day length in some varieties. Ear emergence (50–59), or heading, begins at 51 with the tip pushing out of the sheath, reaching 59 when the full spike or panicle is emerged. In , this occurs 4–6 weeks after tillering ends, with awns visible in around 51. Flowering, or (60–69), starts at 61 with anthers emerging from the middle , peaking at 65 (50% of spikelets flowered), and ends at 69. This 3–5 day window is critical for , with florets opening sequentially from the base upward in . Milk development (70–79) follows, with watery ripe grains (71) progressing to medium milk (75, grains half-filled and milky), building initial grain moisture content. Dough development (80–89) includes early dough (83, grains firm but elastic) to hard dough (87), where endosperm hardens and dry matter accumulates, reaching 89 fully ripe. Kernel weight increases significantly here, up to 80% in barley. Ripening (90–99) concludes with over-ripe grains (92, hard and separating), to 97 (plant death) and 99 (harvested). This senescence phase signals harvest readiness when grains resist thumb pressure.

Feekes Scale

Origins and Methodology

The Feekes scale was developed in 1941 by Dutch agronomist Willem Feekes for describing the growth stages of and other cereals. It was later adapted and popularized in English by E.C. Large in , who illustrated the scale in detail for practical use in crop management. The methodology uses a numerical coding system from 1.0 to 12.0, dividing the crop lifecycle into 12 principal stages based on observable morphological changes, such as leaf development, tillering, and heading. Decimal subdivisions provide finer detail, particularly for tillering (e.g., 2.3 for three tillers) and reproductive phases (e.g., 10.5.1 for early flowering). Staging is determined by examining representative tillers in the field—typically until 50% reach the stage—to account for variability, focusing on the main shoot for consistency. This approach emphasizes vegetative and reproductive phases, aiding decisions on inputs like fertilizers and pesticides across environmental conditions. The scale prioritizes simplicity and visual indicators visible without dissection, making it suitable for field scouting in cereals like , , and oats. It has been widely used in and , though often alongside scales like Zadoks for more granular tracking.

Key Growth Stages

The Feekes scale organizes cereal development into 12 main stages, applicable to and similar grains, with descriptions focusing on external morphology for stages 1 through 12. It tracks progress from to maturity, facilitating timing of agronomic practices. Stage 1 covers , starting at 1.0 with the first leaf breaking through the , subdivided by leaf number (e.g., 1.2 for two leaves). This phase marks the transition from , typically occurring 5-7 days after planting under optimal conditions. Tillering spans stages 2-3, beginning at with the first visible at the main shoot base, advancing to 3.0 when tillering is complete (e.g., 2.4 for four tillers). are auxiliary shoots that boost yield potential, with the phase lasting 4-6 weeks in fall-planted . Stem development includes stages 4-5, where 4.0 indicates the beginning of erect growth with leaf sheaths starting to straighten, and 5.0 when sheaths are strongly erect, signaling post-winter green-up in . This precedes rapid elongation. Jointing at stage 6.0 features the first node becoming visible above the surface, a key point for application and herbicide cutoffs, as the growing point emerges. Stem elongation continues in stages 7-9: 7.0 shows the second node visible, 8.0 the third node and flag leaf sheath extending, and 9.0 the flag leaf blade fully emerged. Plant height increases significantly, doubling in this period for barley and wheat. Booting to heading occurs in stage 10, starting at 10.0 with the head swelling in the flag leaf sheath (boot stage), progressing to 10.5 when half the head is emerged, and 10.9 fully out. Subdivisions track awn or spikelet visibility in cereals like rye. Flowering and grain fill cover stage 11, from 11.1 (milky ripe, kernels soft with liquid content) to 11.4 (hard dough, ready for ). Anthesis begins around 10.5.1-10.5.4, lasting 2-3 days, critical for disease management. Stage 12 denotes full maturity, with the plant ripening uniformly, grains hard and straw dry, indicating readiness. This terminal phase involves , with no subdivisions.

BBCH-Scale for Cereals

Origins and Methodology

The BBCH-scale for cereals was developed in the 1990s through collaborative efforts by a European consortium comprising the Biologische Bundesanstalt (BBA, now part of the Julius Kühn-Institut), the Bundessortenamt (BSA), and representatives from the CHemische Industrie (chemical industry associations like the IVA). This initiative aimed to unify disparate existing growth staging systems, such as the Zadoks and Feekes scales, into a single, harmonized framework to facilitate international communication in agricultural research, crop protection, and variety testing. The methodology employs a coding using two-digit numbers ranging from 00 to 99, where the first digit denotes the principal growth stage (0-9) and the second indicates the secondary stage (0-9) within that phase. This structure allows for precise, quantitative description of phenological development, applicable to cereals as well as other crops, by capturing observable changes in a standardized manner. The scale's principles emphasize a that encompasses both vegetative phases (e.g., and tillering) and reproductive phases (e.g., heading and ), ensuring comprehensive coverage of the lifecycle. It prioritizes internationally agreed-upon observables, such as morphological traits visible on the or shoot, to promote objectivity and across diverse environmental conditions and contexts. The foundational guidelines for the BBCH-scale, including its application to cereals, were outlined in the seminal 1991 publication by et al., which proposed the uniform decimal code. These were extended around 2000 through subsequent monographs and revisions to accommodate a broader range of crops, enhancing the scale's versatility while maintaining its core structure for cereals.

Key Growth Stages

The BBCH scale for cereals organizes plant development into ten principal growth stages, each subdivided into secondary stages using a two-digit code, allowing precise identification of phenological phases across species such as , , oats, and . This structure facilitates uniform communication in , pest management, and research by describing observable morphological changes. Stages 00-09 cover , beginning with the dry (00), progressing through (01-03), (05), (07), and culminating at 09 when the penetrates the surface, marking . In cereals like , this phase typically lasts 5-10 days under optimal conditions, influenced by and moisture. Leaf development spans stages 10-19, starting at 10 with the first emerging through the and advancing to 19 when nine or more leaves are fully unfolded, with a considered unfolded once its is visible or the tip of the subsequent appears. This stage emphasizes the main shoot's vegetative growth, where the number of leaves indicates progress, often reaching 4-6 leaves by the end of the first true phase in and . Tillering occurs in stages 20-29, initiating at 20 with no tillers present and progressing to 21 when the first becomes detectable at the base of the main shoot, up to 29 when the maximum number of tillers is reached, typically 3-5 in under favorable conditions. are side shoots that contribute to yield potential, and this phase overlaps with early development if tillering begins before stage 13. Stem elongation is detailed in stages 30-39, commencing at with the first internode elongating and the pseudostem erect, where the tip is at least 1 cm above the tillering node, and extending to 39 when the flag leaf is fully unrolled with its just visible. Nodes become successively visible (31-36), marking rapid vertical growth. Inflorescence emergence, encompassing booting to heading, is represented by stages 50-59, though booting precedes at 41-49 with the flag leaf sheath extending and swelling. Heading begins at 51 when the inflorescence tip emerges from the sheath, with the first spikelet visible in or , progressing to 59 when the entire (spike or ) is fully emerged. In , awned forms may show awns at 49, while heading in tillers lags 2-3 days behind the . Flowering and cover stages 60-69, starting at 61 with the first anthers visible and extruding from spikelets on the main ear, reaching 65 at full flowering when 50% of anthers are mature, and ending at 69 when all spikelets have flowered, with some dry anthers persisting. For , stage 61 specifically denotes the onset of flowering, a critical window for lasting about 3-5 days. Kernel development unfolds in stages 70-89, from 71 (watery ripe, grains at half final size with liquid ) through milk stages (73 early, 75 medium, 77 late, grains green and milky) to dough stages (83 early, 85 soft, 87 hard) and 89 (fully ripe, grains hard and resistant to thumbnail indentation). This phase builds grain weight, with dry matter accumulation peaking around 87 in . Senescence and dormancy are captured in stages 90-99, advancing from 92 (over-ripe, grains very hard) and 93 (grains loosening) to 97 when the plant is dead and collapsing, and 99 for the harvested product. In cereals, this terminal stage involves leaf yellowing and straw drying, signaling maturity for .

Comparisons and Conversions

Structural Differences

The Zadoks scale organizes development into 10 main stages, numbered from 0 () to 9 (), with each stage subdivided using decimal codes (e.g., 2.1 for the first on the main shoot) to denote finer physiological progress. This structure emphasizes the internal and external physiological changes in , allowing for precise tracking of developmental events like emergence and stem extension through a hierarchical decimal system that supports up to 100 distinct codes overall. In contrast, the Feekes scale employs 11 whole-number primary stages (1 for to 11 for ), with optional decimal subdivisions primarily limited to later phases like heading and filling (e.g., 10.5 for half the emerged), prioritizing straightforward morphological observations for practical field assessment. This design facilitates ease of use by focusing on visible external features such as tiller formation and node visibility, with approximately 11 primary stages and limited subdivisions, resulting in fewer distinct codes than the 100-code systems of Zadoks and BBCH. The BBCH-scale for cereals uses a two-digit coding system ranging from 00 (dry seed) to 99 (harvested product), structured around 10 principal growth stages (e.g., 3 for stem elongation) where the first digit indicates the main phase and the second provides detail for secondary developments, enabling up to 100 codes for comprehensive phenological description. Developed for broad applicability across multiple crops beyond cereals, this format integrates a uniform that accommodates diverse morphologies while maintaining compatibility with cereal-specific adaptations. All three scales fundamentally rely on observable visible traits for staging, such as leaf number or emergence, though the BBCH-scale's extended allows for additional qualifiers in sub-codes to address variations in growth patterns potentially influenced by environmental factors like temperature or moisture. Regarding , the BBCH-scale offers the highest level of detail with its 100-code framework, closely matched by the Zadoks scale's decimal equivalents, whereas the Feekes scale remains the simplest, with its limited primary stages suiting quick morphological evaluations in agronomic practice. These structural variations reflect differing priorities: physiological precision in Zadoks for research-oriented studies, morphological simplicity in Feekes for U.S.-centric field management, and versatile hierarchy in BBCH for international, multi-crop .

Inter-Scale Conversion Methods

Inter-scale conversion methods for cereal growth staging scales rely on approximate mappings derived from shared phenological events, such as leaf emergence, tillering, stem elongation, booting, heading, and grain filling. These conversions facilitate communication across scales like Zadoks, Feekes, and BBCH, which were developed for similar observational criteria but differ in granularity and numbering. For instance, the onset of stem elongation is commonly aligned as Zadoks 30 (beginning of stem extension) ≈ Feekes 6 (jointing, first node visible) ≈ BBCH 31 (first node detectable by dissection). Similarly, the start of tillering corresponds to Zadoks 21 (first tiller) ≈ Feekes 2 (beginning of tillering) ≈ BBCH 21 (side tiller just visible). These alignments are based on the foundational descriptions in the original scale publications and subsequent comparative tools. A representative excerpt from common conversion tables illustrates these correspondences for key stages in and other cereals:
ZadoksFeekesBBCHPhenological Event
00-090-100-09 and emergence
21221Beginning ing (first tiller)
30-315-630-31Stem elongation begins (nodes forming)
451045 (flag leaf sheath swelling)
5910.559 (head) fully emerged
6110.5161Beginning of
8711.387Hard dough stage
9211.492Grain reached maximum mass
This table draws from validated conversion programs and extension resources, focusing on principal transitions rather than every substage. Conversions are inherently approximate and not exact equivalences, as scales like Feekes emphasize visible morphological changes while Zadoks and BBCH incorporate more precise decimal subdivisions that can shift based on cereal variety (e.g., winter vs. spring wheat), environmental factors (e.g., , photoperiod), and observer interpretation. Discrepancies may arise, for example, if tillering vigor varies, leading to offsets of 1-2 substages. To enhance accuracy, visual identification guides and field dissection are essential, rather than relying solely on numerical alignment. Practical tools for inter-scale alignment include published charts from services, such as those developed by and Extension, which provide illustrated comparisons for field use. Software like SCALES 2, a designed to convert among BBCH, Zadoks (ZCK), Feekes, and Haun scales for small grains, offers algorithmic support based on developmental thresholds and has been validated against observational data. Additionally, FAO guidelines on crop incorporate these scales in agronomic recommendations, emphasizing their use in international contexts for timing management practices.

Modern Applications and Extensions

Use in Agronomy and Research

Growth staging scales, such as the Feekes and BBCH scales, are integral to agronomic practices for optimizing input applications in cereal crops like wheat and barley. In weed management, these scales guide the timing of herbicide applications to maximize efficacy while minimizing crop injury; for instance, phenoxy herbicides like 2,4-D are recommended only after full tillering (Feekes 3.0 or BBCH 25-29) to avoid damage to young seedlings. Similarly, most post-emergence herbicide applications should occur before the jointing stage (Feekes 6.0 or BBCH 30-39) to prevent restrictions as the crop advances. For irrigation scheduling, scales identify critical water-sensitive periods, particularly the booting stage (Feekes 10.0 or BBCH 41-49), where deficits can reduce spikelet formation and yield; adequate moisture during this phase ensures proper head development in wheat. In , these scales standardize phenological observations across variety trials, enabling consistent comparisons of genotypes under uniform conditions. Official variety trials, such as those conducted in from 1988 to 2019, use growth stage codes to assess traits like maturity and disease resistance at defined points, facilitating the evaluation of genetic progress in yield and . Additionally, scales support phenological modeling to predict impacts on development; dynamic models incorporating BBCH or Feekes codes simulate shifts in stages like under warming scenarios, revealing potential yield losses from accelerated maturation. Integration with technologies enhances the practical utility of growth staging scales through real-time monitoring. Mobile apps and sensor-based systems, such as those employing UAV , use BBCH codes to detect stages like tillering or , allowing automated alerts for variable-rate inputs in fields. AI-driven platforms further automate stage identification from field imagery, supporting data-driven decisions in precision farming to optimize resource use, including recent models trained on diverse datasets for improved accuracy across species. Case studies in breeding programs demonstrate how scales correlate growth stages with yield components to inform selection. In a multi-year , phenological stages tracked via Zadoks (aligned with BBCH) revealed genetic links between delayed flowering and increased grain number per spike, contributing to yield gains in breeding populations. Similarly, analyses of historical trials showed that extending the stem elongation phase (Feekes 6-9) through breeding positively influenced accumulation and final grain yield, guiding programs toward varieties resilient to environmental stresses.

Adaptations for Other Cereals

The Zadoks scale, originally developed for , has been adapted for through specific descriptors for morphological traits unique to the crop, such as awn emergence at stage 49, when the first awns become visible beyond the flag leaf sheath, aiding in precise timing for agronomic interventions like applications. For oats, regional guidelines in areas like emphasize adjustments to promote earlier flowering (e.g., Zadoks stages 30-49 for stem elongation to ), aligning with autumn rainfall patterns to mitigate and heat stress in varieties like Belar, which supports expanded production of 1.4 million tons of milling oats annually. These adaptations maintain the decimal code structure while incorporating local environmental factors to enhance phenological accuracy across diverse oat genotypes. The Feekes scale extends to , emphasizing external markers like jointing (stage 5) over internal apex events, as documented in comparisons across temperate cereals. The BBCH scale demonstrates versatility for tropical cereals like and through species-specific codes that retain the core two-digit structure but tweak descriptors for non-temperate traits; for , stage 51 marks tassel instead of tillering prominence, while sorghum aligns with cereal codes (e.g., 30-39 for stem elongation) but adjusts for at stage 51 to account for its C4 photosynthetic pathway and heat tolerance. These minor modifications enable direct application in subtropical regions, supporting uniform monitoring of development from (00) to (89). Adapting these scales to presents challenges due to varietal differences and inherently shorter growth cycles, often 90-120 days compared to 150+ for temperate cereals, necessitating compressed staging to capture rapid transitions from vegetative to reproductive phases and avoid misaligned management in drought-prone environments. Genotypic variations, such as those in photoperiod sensitivity, further complicate uniform application, requiring hybrid-specific calibrations to ensure accurate yield predictions. In the , applications of these scales have incorporated climate-resilient varieties through ongoing phenological studies, such as those at Kansas State University's Climate Resilient Cereals Innovation Lab, which use BBCH and Zadoks frameworks to evaluate adaptive traits in and hybrids under projected warming scenarios, though no major structural revisions to the scales themselves have been formalized.

References

  1. https://ahdb.org.uk/knowledge-library/the-growth-stages-of-cereals
  2. https://agriculture.vic.gov.au/crops-and-horticulture/grains-pulses-and-cereals/crop-production/general-agronomy/decimal-growth-scale-of-cereals
  3. https://ohioline.osu.edu/factsheet/agf-126
  4. https://smapvex12.espaceweb.usherbrooke.ca/BBCH_STAGING_MANUAL_CEREALS_CORN.pdf
  5. https://www.dpi.qld.gov.au/__data/assets/pdf_file/0009/1373436/12-518-DL-File-C-Documents-RELEASE.pdf
  6. https://onlinelibrary.wiley.com/doi/10.1111/j.1365-3180.1974.tb01084.x
  7. https://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.1991.tb04895.x
  8. https://www.extension.purdue.edu/extmedia/id/id-422.pdf
  9. https://www.cropscience.bayer.ca/articles/2022/cereal-growth-stages-and-the-application-of-herbicides-and-fungi
  10. https://grdc.com.au/__data/assets/pdf_file/0031/364594/Cereal-growth-stages.pdf
  11. https://atlanticgrainscouncil.ca/wp-content/uploads/2025/07/Factsheet-Cereal-Growth-Stages-May-2025_AM%255E0EW.pdf
  12. https://www.britannica.com/science/taxonomy/The-Linnaean-system
  13. https://doi.org/10.5073/JfK.2009.02.01
  14. https://www.semanticscholar.org/paper/A-decimal-code-for-the-growth-stages-of-cereals-Zadoks/6f036f0378f46b3a8e54d6802b47c9d398759ca1
  15. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3040.1974.tb01403.x
  16. https://extension.umn.edu/growing-small-grains/spring-wheat-growth-and-development-guide
  17. https://www.fao.org/4/y4011e/y4011e06.htm
  18. https://ipcm.wisc.edu/wp-content/uploads/sites/54/2022/11/UW_WheatGrowthStages.pdf
  19. https://www.researchgate.net/publication/281574833_The_BBCH_system_to_coding_the_phenological_growth_stages_of_plants-history_and_publications
  20. https://www.openagrar.de/servlets/MCRFileNodeServlet/openagrar_derivate_00010428/BBCH-Skala_en.pdf
  21. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1083&context=usdaarsfacpub
  22. https://www.ndsu.edu/agriculture/ag-hub/small-grains-development-using-zadoks-feekes-and-haun-scales
  23. https://www.researchgate.net/publication/229530290_A_uniform_decimal_code_for_growth_stages_of_crops_and_weeds
  24. https://www.fao.org/4/x8234e/x8234e05.htm
  25. https://sanangelo.tamu.edu/agronomy/agronomy-publications/growth-stages-of-wheat/
  26. https://agcrops.osu.edu/newsletter/corn-newsletter/2024-10/wheat-management-spring-2024
  27. https://extensionpubs.unl.edu/publication/ec731/na/pdf/view
  28. https://pmc.ncbi.nlm.nih.gov/articles/PMC9958822/
  29. https://pmc.ncbi.nlm.nih.gov/articles/PMC8580907/
  30. https://www.sciencedirect.com/science/article/abs/pii/S1161030104001066
  31. https://www.nature.com/articles/s41598-020-74740-3
  32. https://pubs.rsc.org/en/content/articlehtml/2024/fb/d3fb00101f
  33. https://www.sciencedirect.com/science/article/pii/S264365152400219X
  34. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1070410/full
  35. https://www.biorxiv.org/content/10.1101/2025.04.28.650957v1.full-text
  36. https://www.researchgate.net/figure/Different-barley-developmental-stages-according-to-the-Zadoks-scale-A-At-around-Awn_fig1_316884101
  37. https://pmc.ncbi.nlm.nih.gov/articles/PMC9614419/
  38. https://www.researchgate.net/publication/229700776_Comparison_of_scales_used_for_categorising_the_development_of_wheat_barley_rye_and_oats
  39. https://cropwatch.unl.edu/2021/illustrating-important-growth-stages-winter-cereal-cover-crops/
  40. https://www.researchgate.net/figure/a-BBCH-scale-for-sorghum-in-reference-to-the-cereal-scale-developed-by-Zadoks-etal_fig2_391444741
  41. https://nutrien-ekonomics.com/news/sorghum-development-and-growth-staging/
  42. https://pmc.ncbi.nlm.nih.gov/articles/PMC8793871/
  43. https://www.k-state.edu/news/articles/2025/04/cereals-labs-resumes-work.html
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