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Soybean Reproductive Development Stages

ID

AREC-59NP (SPES-156NP)

Authors as Published

Kevin Dillon, Graduate Research Assistant; David Holshouser, Extension Agronomist

How to Identify Soybean Development Stages

Remove the soybean plant at ground level to make it easier to stage. Examine each main stem node one at a time to determine the development stage. Focus on the top four nodes that contain fully developed leaves (shown below). A fully developed leaf is one that is located immediately below a node containing a leaf with unrolled or unfolded leaflets (leaflet edges are no longer touching). The soybean crop is considered to be at a particular stage when 50% of the plants reach that stage. Listed with stage description for R1 through R6 are the approximate number of days to R7, or physiological maturity, for full season (FS) soybean planted in May and double crop (DC) soybean planted in June/July.

Two photos of the top four nodes that contain fully developed leaves
R1: One open flower at any main stem node

Days to R7 = 68 FS, 57 DC

R2: Open flower at one of two uppermost main stem nodes

Days to R7 = 65 FS, 55 DC

R3: Pod 3/16 inch long at one of four uppermost nodes

Days to R7 = 53 FS, 47 DC

R4: Pod 3/4 inch long at one of four uppermost nodes

Days to R7 = 44 FS, 38 DC

R5: Seed visible in pod at one of four uppermost nodes

Days to R7 = 34 FS, 30 DC

R6: Green seed touching inside pods at one of four uppermost nodes

Days to R7 = 19 FS, 17 DC

R7: One pod on the main stem reached mature color
R8: 95% of pods reached mature color

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Publication Date

July 25, 2019