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Competency Area 2: Crop Staging, Growth and Development

PO 7. Describe the systems used to stage forage legumes and grasses.
&
PO 8. Use the staging systems to identify growth stages of forage legumes and grasses.

Alfalfa - Mean Stage by Count (see also http://css.cals.cornell.edu/cals/css/extension/upload/AlfalfaBulletin.pdf).
The mean stage of maturity by count (MSC) method consists of taking random, representative field samples, and scoring individual stems for stage of development. Stems in the vegetative stages are scored 0-2, bud stage 3-4, flowering 5-6, and seed production 7-9. The MSC is calculated as the weighted mean stage of all stems collected in the sample.
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staging alfalfa

Stage 0: Early vegetative. Stem length < 6 inches. 

staging alfalfa

Stage 1: Mid-vegetative. Stem length 6-12 inches. 

staging alfalfa

Stage 2: Late vegetative. Stem length > 12 inches (no visible buds). 

staging alfalfa

Stage 3: Early bud. 1-2 nodes with visible buds.

staging alfalfa

Stage 4: Late bud. > 3 nodes with visible buds. 

staging alfalfa 

Stage 5: Early flower. One node with one open flower.

staging alfalfa

Stage 6: Late flower. > 2 nodes with open flowers. 

staging alfalfa

Stage 7: Early seed pod. 1-3 nodes with green seed pods. 

staging alfalfa

Stage 8: Late seed pod. > 4 nodes with green seed pods. 

staging alfalfa

Stage 9: Ripe seed pod. Nodes with brown mature seed pods. 

Perennial grass staging system
Perennial grass proceeds through a sequence of developmental stages: 1) germination, 2) vegetative; 3) elongation; 4) reproductive, and 5) seed ripening. The vegetative growth period is characterized by the development of leaves. Elongation is the period during which stem internodes elongate and is also referred to as jointing. During elongation the developing inflorescence pushes through the uppermost leaf sheath commonly referred to as boot stage. The reproductive stage is the period during which the developing inflorescence emerges and pollination occurs.

Information on quantifying growth stages can be found at (Moore et al. (1991) Describing and Quantifying Growth Stages of Perennial Forage Grasses. Agron. J. 83:1073). The five growth stages above have been related to a continuous numerical index. Germination stages are numbered from 0 to 0.9 and seed production stages are numbered from 4.0 to 4.9 on the numerical scale. Vegetative stages 1.0 to 1.9 start with emergence of first leaf and the index increases with each additional collared leaf. Elongation stages range from 2.0 to 2.9 starting with onset of elongation and the index increases with each additional palpable/visible node. The Reproductive stages range from 3.0 to 3.9 and start with boot stage. The emergence of the inflorescence through post-anthesis is included. Each stage of the system also has a mnemonic code (e.g. R1 = inflorescence emergence).

Primary and secondary growth stages and their numerical indices and descriptions for staging growth and development of perennial grasses.

Stage

Index

Description

Germination

G0

0.0

Dry seed

G1

0.1

Imbibition

G2

0.3

Radicle emergence

G3

0.5

Coleoptile emergence

G4

0.7

Mesocotyl and/or coleoptile elongation

G5 from soil

0.9

Coleoptile emergence from soil

Vegetative-Leaf development

VE or V0

1.0

Emergence of first leaf

V1

 (1/N)+0.9

First leaf collared

V2

 (2/N)+0.9

Second leaf collared

Vn

 (n/N)+0.9

Nth leaf collared

Elongation-Stem elongation

E0

2.0

Onset of stem elongation

E1

 (1/N)+1.9

First node palpable/visible

E2

 (2/N)+1.9

Second node palpable/visible

En

(n/N)+1.9

Nth node palpable/visible

Reproductive-Floral development

R0

3.0

Boot stage

R1

3.1

Inflorescence emergence/1st spikelet visible

R2

3.3

Spikelets fully emerged/peduncle not emerged

R3

3.5

Inflorescence emerged /peduncle fully elongated

R4

3.7

Anther emergence/anthesis

R5

3.9

Post anthesis/fertilization

Seed development and ripening

S0

4.0

Caryopsis visible

S1

4.1

Milk

S2

4.3

Soft dough

S3

4.5

Hard dough

S4

4.7

Endosperm hard/physiological maturity

S5

4.9

Endosperm dry/seed ripe