Soybean Growth Stages Chad Lee, Ph.D. Grain Crops Extension Specialist University of Kentucky

► How a Soybean Plant Develops, Special Report No. 53 ► Iowa State University Press ► $2.00  Extension Distribution Center 119 Printing and Publications Building Iowa State University Ames, Iowa Telephone: (515) Fax: (515)  an/bean_develop/ The information in the presentation comes from Iowa State Special Report No.53. This is an excellent resource for any producer or agronomist.

Vegetative Stages Reproductive Stages VER1 VCR2 V1R3 V2R4 V3R5 V(n)R6 R7 R8

Vegetative Stages Reproductive Stages VE – emergence R1 – beginning bloom VC – cotyledon R2 – full bloom V1 – 1 st node R3 – beginning pod V2 – 2 nd node R4 – full pod V3 – 3 rd node R5 – beginning seed V(n) – n th node R6 – full seed R7 – beginning maturity R8 – full maturity

VEVC

“Poking through” hypocotyl

VC V1

V2 Rhizobia have colonized the roots. N – fixation has begun. The roots are growing through the top 6 inches of soil.

V3

V5V6 Axillary Buds 1)Form flowers that develop into pods 2)Form axillary stems, which form more axillary buds 3)Remain dormant

V5V6 Apex (Growing Point) 1)Dominant in vegetative growth (plant will grow up before growing out) 2)If the apex is destroyed, the axillary buds will produce many stems, causing the plant to “bush out”.

V7R1

R2 – Full Flower

R2

R3 – Beginning pod

R4 – Full Pod

Start of the most critical period for yield determination. From R4 through R6, yield potential is more susceptible to stress than any other period.

R5 – Beginning Seed

R6 – Full Seed

R7 – Beginning Maturity

R6R8

Vegetative Stages Reproductive Stages VE – emergence R1 – beginning bloom VC – cotyledon R2 – full bloom V1 – 1 st node R3 – beginning pod V2 – 2 nd node R4 – full pod V3 – 3 rd node R5 – beginning seed V(n) – n th node R6 – full seed R7 – beginning maturity R8 – full maturity

Thank you!