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Compendium of Growth Stage Identification Keys for Mono- and Dicotyledonous Plants

The extended BBCH-scale

BBCH is derived from the Biologische Bundesanstalt, Bundessortenamt and CHemical industry and is the system used for uniform coding of phenologically similar growth stages of all mono- and dicotyledonous plant species.

The basic scale principles

A general scale provides the framework within which the individual scales within the extended scale are developed and in turn used for plant species for which currently no specific scale is available.

Therefore:

  • similar phenological stages of each plant species are given the same code
  • a description, including the important stages are included for each code
  • clear, easily recognised external morphological characteristics are used to describe the phenological developmental stages
  • only the development of the main stem is taken into consideration except where otherwise stated
  • The growth stages are representative of individual plants within a crop stand although crop stand characteristics may also be considered
  • An indication of size, relative values are used relating to species and/or the ultimate size of the variety
  • Respective ordinal numbers or percentage values correspond to the secondary growth stages 0 to 8 and therefore stage 3 could represent the 3 rd true leaf, 3rd tiller, 3rd node of the final length or size of the typical species or 30% of the flowers open
  • Post harvest or storage treatment is coded 99
  • Seed treatment before planting is coded 00

The scale organisation

The principal growth stages

The entire developmental cycle of the plants is subdivided into ten clearly recognisable developmental phases (coded by using the figures 0 to 9) known as principal growth stages described in Table 1. Different plant species have varying courses of development therefore there may be shifts in certain principal growth stages with some even being omitted. The system of ascending numbers describing the principal growth stages do not necessarily provide a strict sequence of events, as on occasion some may run in parallel.

If two or more growth stages proceed in parallel it will be indicated by a parallel stroke i.e. 16/22. If only one stage is to be indicated where two are shown then either the more advanced growth stage or the principal growth stage of interest (dependant on plant species) must be chosen.

The secondary growth stages

The principal growth stages alone are not sufficient to define the exact dates for application or evaluation. If points of time or steps in the plant development must be indicated precisely, secondary stages are used. Secondary stages are defined as short developmental steps, characteristic of the respective plant species that are passed successively during the respective principal growth stage. Secondary stages are also coded using the figures 0 to 9.

Combining the figures for the principal and secondary stage results in the production of a two-digit code that offers the possibility of precisely defining all phenological growth stages for the majority of plant species.

The meso-stage sub-divisions

Further subdivision are required within the principal growth stage beyond that possible using the secondary growth stages for species such as cucumber, onion, potato, soybean, and tomato. In these cases a three-digit scale is presented alongside the two-digit scale with the inclusion of a meso-stage sub-division with the figures 0 and 1 to describe the development of the main stem and figure 2 to 9 describing the development of the side shoots. Using this method up to 19 leaves can be counted on the main stem or the branching can be described.

Comparison of individual codes

The BBCH-scale allows the comparison of individual codes only within one principal growth stage: an arithmetically greater code indicates a plant at a later growth stage. Sorting codes into numerical order therefore allows a listing in order of the stage of plant development.

By indicating two stages, the time span of a certain developmental phase can be exactly defined and coded with the two codes used being connected with a hyphen. Hence, code 51-69 describes the developmental phase incorporating the first inflorescence or flower buds until the end of flowering.

In order to use primarily phenological criteria rather than homologous or analogous stages, a uniform coding which covers the maximum number of plant species is required. Therefore the germination of plants from one true seed and the sprouting of buds are classified in one principal growth stage, classified a 0 even though they are completely different biological processes.

The descriptions used within the BBCH-scales are based on actual characteristic features of the individual plant and should apply to at least 50% of the plants if the scales are used for the definition of the development stage of a plant stand.

Within the description of the general scale, the greater differences in the course of the development of different plant groups have been taken into consideration by offering several definition for one specific stage wherever the formulation of a uniform text is impossible.

Principal growth stages

0. Germination/sprouting/bud development
1. Leaf development (main shoot)
2. Formation of side shoots/tillering
3. Stem elongation of rosette growth/shoot development (main shoot)
4. Development of harvestable vegetative plant parts or vegetatively
    propagated organs/booting (main shoot)
5. Inflorescence emergence (main shoot)/heading
6. Flowering (main shoot)
7. Development of fruit
8. Ripening or maturity of fruit and seed
9. Senescence, beginning of dormancy

The extended BBCH-scale, general

D = Dicotyledons
M = Monocotyledons
V = Development from vegetative parts or propagated organs
G = Gramineae
P = Perennial plants

No code letter is used if the description applies to all groups of plants.

Principal growth stage 0: Germination, sprouting, bud development

Code Plant Description
00   Dry seed (see dressing takes place at stage 00)
  P, V Winter dormancy or resting period
01   Beginning of seed inhibition
  P, V Beginning of bud swelling
03   Seed inhibition complete
  P, V End of bud swelling
05   Radicle (root) emerged from seed
  P, V Perennating organs forming roots
06   Elongation of radicle , formation of root hairs and/or lateral roots
07 G Coleoptile emerged from caryopsis
  D, M Hypocotyl with cotyledons or shoot breaking through seed coat
  P, V Beginning of sprouting or bud breaking
08   Hypocotyl with cotyledons growing towards soil surface
  P, V Shoot growing towards soil surface
09 G Emergence: Coleoptile breaks through soil surface
  D, M Emergence: Cotyledons break through soil surface (except hypogeal germination)
  D, V Emergence: Shoot/leaf breaks through soil surface
  P Bud shows green tips

Principal growth stage 1: Leaf development (main shoot)

Code Plant Description
10 G First true leaf emerged from coleoptile
  D, Cotyledons completely unfolded
  P First leaves separated
11   First true leaf, leaf pair or whorl unfolded
  P First leaves unfolded
12   2 true leaves, leaf pairs or whorls unfolded
13   3 true leaves, leaf pairs or whorls unfolded
1   Stages continuous till
19   9 or more true leaves, leaf pairs or whorls unfolded

Principal growth stage 2: Formation of side shoots/tillering

Code Plant Description
21   First side shoot visible
  G First tiller visible
22   2 side shoots visible
  G 2 tillers visible
23   3 side shoots visible
  G 3 tillers visible
2   Stages continuous till
29   9 or more side shoots visible
  G 9 or more tillers visible

Principal growth stage 3: Stem elongation or rosette growth, shoot development (main shoot)

Code Plant Description
31   Stem (rosette) 10% of final length (diameter)
  G 1 node detectable
32   Stem (rosette) 20% of final length (diameter)
  G 2 nodes detectable
33   Stem (rosette) 30% of final length (diameter)
  G 3 nodes detectable
3   Stages continuous till
39   Maximum stem length or rosette diameter reached
  G 9 or more nodes detectable

Principal growth stage 4: Development of harvestable vegetative plant parts or vegetatively propagated organs/booting (main shoot)

Code Plant Description
40   Harvestable vegetative plant parts or vegetatively propagated organs begin to develop
41 G Flag leaf sheath extending
43   Harvestable vegetative plant parts or vegetatively propagated organs have reached 30% of final size
  G Flag leaf sheath just visibly swollen (mid-boot)
45   Harvestable vegetative plant parts or vegetatively propagated organs have reached 50% of final size
  G Flag leaf sheath swollen (late-boot)
47   Harvestable vegetative plant parts or vegetatively propagated organs have reached 70% of final size
  G Flag leaf sheath opening
49   Harvestable vegetative plant parts or vegetatively propagated organs have reached final size
  G First awns visible

Principal growth stage 5: Inflorescence emergence (main shoot)/heading

Code Plant Description
51 Inflorescence or flower buds visible
G Beginning of heading
55 First individual flowers visible (still closed)
G Half of inflorescence emerged (middle of heading)
59 First flower petals visible (ion petalled forms)
G Inflorescence fully emerged (end of heading)

Principal growth stage 6: Flowering (main shoot)

Code Plant Description
60   First flowers open (sporadically)
61   Beginning of flowering: 10% of flowers open
62   20% of flowers open
63   30% of flowers open
64   40% of flowers open
65   Full flowering: 50% of flowers open, first petals may be fallen
67   Flowering finishing: majority of petals fallen or dry
69   End of flowering: fruit set visible

Principal growth stage 7: Development of fruit

Code Plant Description
71   10% of fruits have reached final size or fruit has reached 10% of final size
  G Caryopsis watery ripe
72   20% of fruits have reached final size or fruit has reached 20% of final size
73   30% of fruits have reached final size or fruit has reached 30% of final size
  G Early milk
74   40% of fruits have reached final size or fruit has reached 40% of final size
75   50% of fruits have reached final size or fruit has reached 50% of final size
  G Milky ripe, medium milk
76   60% of fruits have reached final size or fruit has reached 60% of final size
77   70% of fruits have reached final size or fruit has reached 70% of final size
  G Late milk
78   80% of fruits have reached final size or fruit has reached 80% of final size
79   Nearly all fruits have reached final size

Principal growth stage 8: Ripening or maturity of fruit and seed

Code Plant Description
81   Beginning of ripening or fruit colouration
85   Advanced ripening or fruit colouration
  G Dough stage
87   Fruit begins to soften (species with fleshy fruit)
89   Fully ripe: fruit shows fully-ripe colour, beginning of fruit abscission

Principal growth stage 9: Senescence, beginning of dormancy

Code Plant Description
91 P Shoot development completed, foliage still green
93   Beginning of leaf-fall
95   50% of leaves fallen
97   End of leaf fall, plants or above ground parts dead or dormant
  P Plant resting or dormant
99   Harvested product (post-harvest or storage treatment is applied at stage 99)
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