In biology, the BBCH-scale for citrus describes the phenological development of citrus plants using the BBCH-scale.
The phenological growth stages and BBCH-identification keys of citrus plants are:
| Growth stage | Code | Description |
|---|---|---|
| 0: Sprouting/Bud development | 00 | Dormancy: leaf and inflorescence buds undifferentiated, closed and covered by green scales |
| 01 | Beginning of bud swelling | |
| 03 | End of bud swelling: green scales slightly separated | |
| 07 | Beginning of bud burst | |
| 09 | Green leaf tips visible | |
| 1: Leaf development | 10 | First leaves separating: green scales slightly open, leaves emerging |
| 11 | First leaves visible1 | |
| 15 | More leaves visible, not yet at full size | |
| 19 | First leaves fully expanded | |
| 3: Shoot development | 31 | Beginning of shoot growth: axes of developing shoots visible |
| 32 | Shoots about 20% of final length | |
| 39 | Shoots about 90% of final length | |
| 5: Inflorescence emergence | 51 | Inflorescence buds swelling: buds closed, light green scales visible |
| 53 | Bud burst: scales separated, floral tips visible | |
| 55 | Flowers visible, still closed (green bud), borne on single or multiflowered leafy or leafless inflorescences | |
| 56 | Flower petals elongating; sepals covering half corolla (white bud) | |
| 57 | Sepals open: petal tips visible; flowers with white or purplish petals, still closed | |
| 59 | Most flowers with petals forming a hollow ball | |
| 6: Flowering | 60 | First flowers open |
| 61 | Beginning of flowering: about 10% of flowers open | |
| 65 | Full flowering: 50% of flowers open; first petals falling | |
| 67 | Flowers fading: majority of petals fallen | |
| 69 | End of flowering: all petals fallen | |
| 7: Development of fruit | 71 | Fruit set; beginning of ovary growth; beginning of fruitlets abscission |
| 72 | Green fruit surrounded by sepal crown | |
| 73 | Some fruits slightly yellow: beginning of physiological fruit drop | |
| 74 | Fruits about 40% of final size. Dark green fruit: end of physiological fruit drop | |
| 79 | Fruits about 90% of final size | |
| 8: Maturity of fruit | 81 | Beginning of fruit colouring (colour-break) |
| 83 | Fruit ripe for picking; fruit has not yet developed variety-specific colour | |
| 85 | Advanced ripening; increase in intensity of variety-specific colour | |
| 89 | Fruit ripe for consumption; fruit has typical taste and firmness; beginning of senescence and fruit abscission | |
| 9: Senescence, beginning of dormancy | 91 | Shoot growth complete; foliage fully green |
| 93 | Beginning of senescence and abscission of old leaves | |
| 97 | Winter dormancy period |
1 In Citrus the term "visible" replaces "unfolded" used for other fruit species. Leaf unfolding takes place precociously in citrus
Agusti, M.; S. Zaragoza, H. Bleiholder, L. Buhr, H. Hack, R. Klose, R. Stauss (1995). "Escala BBCH para la descripción de los estadios fenológicos del desarrollo de los agrios (Gén. Citrus)". Levante Agricola 3: 189–199.