Soybean Phenology Descriptions


Vegetative Stages

Stage no. Abbreviated stage title Description
VE Emergence Cotyledons above the soil surface
V1 First node Fully developed leaves at unifoliolate nodes
V2 Second node Fully developed trifoliolate leeav at node above the unifoliolate nodes nodes
V3 Third node Three nodes on the main stem with fully develped leaves begining with the unifoliolate nodes
Vn nth node n number of nodes on the main stem with fully developed leaves begining with the unifoliolate nodes.


Reproductive Stages

Stage no. Abbreviated stage title Description
R1 Begining bloom One open flower at any node on the main stem
R2 Full bloom Open flower at one of the two uppermost nodes on the main stem with a fully develped leaf
R3 Begining pod Pod 5 mm (3/16 inch) long at one of the four uppermost nodes on the main stem with a fully developed leaf
R4 Full pod Pod 2 cm (3/4 inch) long at one of the four uppermost nodes on the main stem with a fully developed leaf
R5 Begining seed Seed 3mm (1/8 inch) long in a pod at one of the four uppermost nodes on the main stem with a fully developed leaf
R6 Full seed Pod containing green seed that fills the pod cavity at one of the four uppermost nodes on the main stem with a fully developed leaf
R7 Begining maturity One normal pod on the main stem that has reached its mature pod color
R8 Full maturity Ninety-five percent of the pods that have reached their mature pod color


Stages Illustration

R1
R2
R3
R4
R5
R6
R7


References

Fehr, W.R., Caviness, C.F., Burmood, D.T., Pennington, J.S., 1971. Stage of development descriptions for soybeans, Glycine max (L.) Merrill. Crop Sci. 11, 929-931.

Fehr, W.R., Caviness, C.E., 1977. Stages of soybean development. Cooperative Extension Service, Agriculture and Home Economics Experiment Station, Iowa State University, Ames, Iowa.