BBCH-scale (cotton)

In biology, the BBCH-scale for cotton describes the phenological development of cotton plants Gossypium hirsutum using the BBCH-scale.

The phenological growth stages and BBCH-identification keys of cotton are:

Growth stage	Code	Description
0: Germination	00	Dry seed
	01	Beginning of seed imbibition
	03	Seed imbibition complete
	05	Radicle emerged from seed
	06	Elongation of radicle
	07	Hypocotyl with cotyledons breaking through seed coat
	08	Hypocotyl with cotyledons growing towards soil surface
	09	Emergence: hypocotyl with cotyledons breaking through soil surface ("crook stage")
1: Leaf development (Main shoot)	10	Cotyledons completely unfolded1
	11	First true leaf unfolded1
	12	2nd true leaf unfolded1
	13	3rd true leaf unfolded1
	1 .	Stages continuous till ...
	19	9 or more true leaves unfolded;1 no side shoots visible2
2: Formation of side shoots3	21	First vegetative side shoot (2nd order) visible
	22	2 vegetative side shoots (2nd order) visible
	23	3 vegetative side shoots (2nd order) visible
	2 .	Stages continuous till ...
	29	9 or more vegetative side shoots (2nd order) visible
3: Main stem elongation (Crop cover)	31	Beginning of crop cover: 10% of plants meet between rows
	32	20% of plants meet between rows
	33	30% of plants meet between rows
	34	40% of plants meet between rows
	35	50% of plants meet between rows
	36	60% of plants meet between rows
	37	70% of plants meet between rows
	38	80% of plants meet between rows
	39	Canopy closure: 90% of the plants meet between rows
5: Inflorescence emergence (Main shoot)	51	First floral buds detectable ("pin-head square")4
	52	First floral buds visible ("match-head square")4
	55	Floral buds distinctly enlarged
	59	Petals visible: floral buds still closed
6: Flowering	60	First flowers opened (sporadically within the population)
	61	Beginning of flowering ("Early bloom"): 5–6 blooms / 25 ft of row (= 5–6 blooms / 7.5 meter of row)
	65	Full flowering: ("Mid bloom"): 11 and more blooms / 25 ft of row = 11 and more blooms / 7.5 meter of row
	67	Flowering finishing: majority of flowers faded ("Late bloom")
	69	End of flowering
7: Development of fruits and seeds	71	About 10% of bolls have attained their final size
	72	About 20% of bolls have attained their final size
	73	About 30% of bolls have attained their final size
	74	About 40% of bolls have attained their final size
	75	About 50% of bolls have attained their final size
	76	About 60% of bolls have attained their final size
	77	About 70% of bolls have attained their final size
	78	About 80% of bolls have attained their final size
	79	About 90% of bolls have attained their final size
8: Ripening of fruits and seeds	80	First open bolls on the first fruiting branches
	81	Beginning of boll opening: about 10% of bolls open. Nodes Above White Flower (NAWF)
	82	About 20% of bolls open
	83	About 30% of bolls open. Nodes Above Cracked Boll (NACB)
	84	About 40% of bolls open
	85	About 50% of bolls open
	86	About 60% of bolls open
	87	About 70% of bolls open
	88	About 80% of bolls open
	89	About 90% of bolls open
9: Senescence	91	About 10% of leaves discoloured or fallen
	92	About 20% of leaves discoloured or fallen
	93	About 30% of leaves discoloured or fallen
	94	About 40% of leaves discoloured or fallen
	95	About 50% of leaves discoloured or fallen
	96	About 60% of leaves discoloured or fallen
	97	Above ground parts of plant dead; plant dormant
	99	Harvested product (bolls and seeds)

1 Leaves are counted from the cotyledon node (= node 0)
2 Side shoot development may occur earlier, if there is a vegetative side shoot continue with principal growth stage 2. If there is a reproductive side shoot (fruiting branch) continue with the principal growth stage 5
3 Vegetative side shoots are counted from the cotyledon node
4 "pin-head square" or "match-head square" is the first square which forms at the first fruiting position of the first fruiting branch

References

• Munger, L.; H. Bleiholder; H. Hack; M. Hess; R. Stauss; T. van den Boom; E. Weber (1998). "Phenological Growth Stages of the Peanut plant (Arachis hypogaea L.) Codification and Description according to the BBCH Scale – with figures". Journal of Agronomy and Crop Science. 180 (2): 101–107. doi: 10.1111/j.1439-037X.1998.tb00377.x .