The growth stages of oilseed rape

It is useful to break down the life cycle of oilseed rape into various growth stages. By understanding the main crop development stages, it becomes easier to measure crop performance and informs husbandry choices.

Oilseed rape growth guide home

What are growth stages and why are they important?

A plant’s life cycle can be described by ten developmental phases.

Understanding the principal growth stages (GS) can help assist with management decisions. For example, this uniform coding system, which is also used for cereals, features on plant protection product labels.

There are two systems in use: The BBCH (Biologische Bundesanstalt, Bundessortenamt und CHemical Industry) and AAB scales. Although there are striking similarities, there are also some key differences between them.

Although the principal growth stages start in chronological order, the beginning of each stage is not dependent on the completion of the preceding stage. As a result, several stages overlap. Where overlaps occur, the guidance is to use the GS for the most advanced stage (e.g. the higher number). How quickly the crop moves through each stage depends on its environment and the variety.

Principal growth stages (BBCH system)

Principal growth and secondary growth stage keys

BBCH system

GS0: Germination and emergence

00: Seed dry

01: Seed imbibition starts

03: Seed imbibition complete

05: Radicle (embryonic root) emerged from seed

07: Cotyledons emerged from seed

09: Cotyledons emerged through soil surface

GS1: Leaf development

10: Cotyledons completely unfolded

11: First leaf unfolded

12: Second leaf unfolded

19: Nine or more leaves unfolded

GS2: Side-shoot formation

20: No side shoots

21: First side shoot detectable

22: Second side shoot detectable

29: Nine or more side shoots detectable

GS3: Stem elongation/extension

30: No internodes (rosette stage)

31: One visibly extended internode

32: Two visibly extended internodes

39: Nine or more visibly extended internodes

GS4: Does not apply to oilseed rape

GS5: Inflorescence/flower-bud emergence

50: Flower buds present and enclosed by leaves

51: Flower buds visible from above (‘green bud’ stage)

52: Flower buds free and level with the youngest leaves

53: Flower buds raised above the youngest leaves

55: Individual flower buds (main inflorescence) visible but closed

57: Individual flower buds (secondary inflorescences) visible but closed

59: Flower buds closed with first petals visible (‘yellow bud’ stage)

GS6: Flowering

60: First flowers open

61: 10% of flowers on main raceme open

62: 20% of flowers on main raceme open

65: 50% flowers on main raceme open, older petals falling (‘full flower’ stage)

67: Flowering declining, most petals fallen

69: End of flowering

GS7: Pod/seed (fruit) development

71: 10% of pods have reached final size

72: 20% of pods have reached final size

79: >90% of pods have reached final size

GS8: Pod/seed (fruit) ripening

80: Ripening starts (seeds green and filling pod cavity)

81: 10% of pods ripe, with seeds dark and hard

82: 20% of pods ripe, with seeds dark and hard

89: >90% nearly all pods ripe, with seeds dark and hard

GS9: Senescence

90: Plant death starts

97: Plant dead and dry

99: Harvested product

*Adapted from ‘Growth stages of mono- and dicotyledonous plants’ (BBCH Monograph), 2001.

AAB system

GS0: Germination and emergence

0.0: Dry seed

0.9: Cotyledons emerge through soil surface

GS1: Leaf production

1.0: Cotyledons unfolded

1.1: First true leaf

1.2: Second true leaf

1.6: Sixth true leaf

GS2: Stem extension

2.0: No internodes (rosette)

2.1: One internode

2.2: Two internodes

2.5: Five internodes

GS3: Flower-bud development

3.0: No flower buds present (only leaf buds present)

3.1: Flower buds enclosed by leaves

3.3: First flower buds visible from above ('green bud')

3.5: First flower buds raised above leaves

3.6: First flower stalks extending

3.7: First flower buds yellow ('yellow bud')

GS4: Flowering

4.0: First flower opened

4.1: 10% of flower buds opened

4.2: 20% of flower buds opened

4.5: 50% of flower buds opened

GS5: Pod development

5.0: 0% of potential pods

5.1: 10% of potential pods

5.2: 20% of potential pods

5.5: 50% of potential pods

GS6: Seed development

6.0: No seeds expanding

6.1: Seeds expanding

6.2: Most seeds translucent but full size

6.3: Most seeds green

6.4: Most seeds green-brown mottled

6.5: Most seeds brown

6.6: Most seeds dark brown

6.7: Most seeds black but soft

6.8: Most seeds black and hard

6.9: All seeds black and hard

GS7: Leaf senescence

GS8: Stem senescence

8.0: All stem green

8.1: Most stem green

8.5: Half stem green

8.9: Little stem green

GS9: Pod senescence

9.0: All pods green

9.1: Most pods green

9.5: Half pods green

9.9: Few pods green

*Adapted from Sylvester-Bradley, 1985. Aspects of Applied Biology 10: 395–400