Cereal growth staging scales attempt to objectively measure the growth of cereals.
BBCH-scale (cereals) In agronomy, the BBCH-scale for cereals describes the phenological development of cereals using the BBCH-scale.
The phenological growth stages and BBCH-identification keys of cereals are: Growth stageCodeDescription0: Germination00 Dry seed (caryopsis)01 Beginning of seed imbibition03 Seed imbibition complete05 Radicle emerged from caryopsis06 Radicle elongated, root hairs and/or side roots visible07 Coleoptile emerged from caryopsis09 Emergence: coleoptile penetrates soil surface (cracking stage)1: Leaf development1, 210 First leaf through coleoptile11 First leaf unfolded12 2 leaves unfolded13 3 leaves unfolded1 . Stages continuous till ...19 9 or more leaves unfolded2: Tillering320 No tillers21 Beginning of tillering: first tiller detectable22 2 tillers detectable23 3 tillers detectable2 . Stages continuous till ...29 End of tillering. Maximum no. of tillers detectable3: Stem elongation30 Beginning of stem elongation: pseudostem and tillers erect, first internode begins to elongate, top of inflorescence at least 1 cm above tillering node31 First node at least 1 cm above tillering node32 Node 2 at least 2 cm above node 133 Node 3 at least 2 cm above node 23 . Stages continuous till ...37 Flag leaf just visible, still rolled39 Flag leaf stage: flag leaf fully unrolled, ligule just visible4: Booting41 Early boot stage: flag leaf sheath extending43 Mid boot stage: flag leaf sheath just visibly swollen45 Late boot stage: flag leaf sheath swollen47 Flag leaf sheath opening49 First awns visible (in awned forms only)5: Inflorescence emergence, heading51 Beginning of heading: tip of inflorescence emerged from sheath, first spikelet just visible52 20% of inflorescence emerged53 30% of inflorescence emerged54 40% of inflorescence emerged55 Middle of heading: half of inflorescence emerged56 60% of inflorescence emerged57 70% of inflorescence emerged58 80% of inflorescence emerged59 End of heading: inflorescence fully emerged6: Flowering, anthesis61 Beginning of flowering: first anthers visible65 Full flowering: 50% of anthers mature69 End of flowering: all spikelets have completed flowering but some dehydrated anthers may remain7: Development of fruit 71 Watery ripe: first grains have reached half their final size73 Early milk75 Medium milk: grain content milky, grains reached final size, still green77 Late milk8: Ripening83 Early dough85 Soft dough: grain content soft but dry. Fingernail impression not held87 Hard dough: grain content solid. Fingernail impression held89 Fully ripe: grain hard, difficult to divide with thumbnail9: Senescence92 Over-ripe: grain very hard, cannot be dented by thumbnail93 Grains loosening in day-time97 Plant dead and collapsing99 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. This scale is more widely used in the United States than other similar and more descriptive 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 scaleStageDescriptionTillering1 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 Extension6 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.Ripening11.1 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 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 scalesZadokScaleFeekesScale HaunScaleDescriptionGermination 00 Dry seed 01 Start of imbibition 03 Imbibition complete 05 Radicle emerged from seed07 Coleoptile emerged from seed 09 0.0Leaf 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 8-9Flag leaf sheath extending 45 109.2Boots just swollen 47 Flag leaf sheath opening 49 10.1First awns visible Inflorescence emergence 50 10.110.2First spikelet of inflorescence visible 53 10.2 1/4 of inflorescence emerged 55 10.310.51/2 of inflorescence emerged 57 10.410.73/4 of inflorescence emerged 5910.511.0Emergence of inflorescence completed Anthesis 6010.5111.4Beginning on anthesis 65 11.5Anthesis half-way 69 11.6Anthesis completed Milk development 70 - 71 10.5412.1Kernel watery ripe 73 13.0Early milk 7511.1 Medium milk 77 Late milk Dough development 80 - 83 14.0Early dough 8511.2 Soft dough 87 15.0 Hard dough Ripening 90 - 9111.3 Kernel hard (difficult to divide with thumbnail) 9211.416.0Kernel 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
Further reading J.C. Zadoks, T.T. Chang, C.F. Konzak, "A Decimal Code for the Growth Stages of Cereals", Weed Research 1974 14:415-421.
External links Citation Classic of 1985