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 stageCodeDescription0: Germination00 Dry seed01 Beginning of seed imbibition03 Seed imbibition complete05 Radicle emerged from seed06 Elongation of radicle07 Hypocotyl with cotyledons breaking through seed coat08 Hypocotyl with cotyledons growing towards soil surface09 Emergence: hypocotyl with cotyledons breaking through soil surface ("crook stage")1: Leaf development (Main shoot)10 Cotyledons completely unfolded111 First true leaf unfolded112 2nd true leaf unfolded113 3rd true leaf unfolded11 . Stages continuous till ...19 9 or more true leaves unfolded;1 no side shoots visible22: Formation of side shoots321 First vegetative side shoot (2nd order) visible22 2 vegetative side shoots (2nd order) visible23 3 vegetative side shoots (2nd order) visible2 . Stages continuous till ...29 9 or more vegetative side shoots (2nd order) visible3: Main stem elongation (Crop cover)31 Beginning of crop cover: 10% of plants meet between rows32 20% of plants meet between rows33 30% of plants meet between rows34 40% of plants meet between rows35 50% of plants meet between rows36 60% of plants meet between rows37 70% of plants meet between rows38 80% of plants meet between rows39 Canopy closure: 90% of the plants meet between rows5: Inflorescence emergence (Main shoot)51 First floral buds detectable ("pin-head square")452 First floral buds visible ("match-head square")455 Floral buds distinctly enlarged59 Petals visible: floral buds still closed6: Flowering60 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 row67 Flowering finishing: majority of flowers faded ("Late bloom")69 End of flowering7: Development of fruits and seeds71 About 10% of bolls have attained their final size72 About 20% of bolls have attained their final size73 About 30% of bolls have attained their final size74 About 40% of bolls have attained their final size75 About 50% of bolls have attained their final size76 About 60% of bolls have attained their final size77 About 70% of bolls have attained their final size78 About 80% of bolls have attained their final size79 About 90% of bolls have attained their final size8: Ripening of fruits and seeds80 First open bolls on the first fruiting branches81 Beginning of boll opening: about 10% of bolls open. Nodes Above White Flower (NAWF)82 About 20% of bolls open83 About 30% of bolls open. Nodes Above Cracked Boll (NACB)84 About 40% of bolls open85 About 50% of bolls open86 About 60% of bolls open87 About 70% of bolls open88 About 80% of bolls open89 About 90% of bolls open9: Senescence91 About 10% of leaves discoloured or fallen92 About 20% of leaves discoloured or fallen93 About 30% of leaves discoloured or fallen94 About 40% of leaves discoloured or fallen95 About 50% of leaves discoloured or fallen96 About 60% of leaves discoloured or fallen97 Above ground parts of plant dead; plant dormant99 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
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