Soybean Growth Soybean Growth StagesStages

Chad Lee, Ph.D.Chad Lee, Ph.D.

Grain Crops Extension Grain Crops Extension SpecialistSpecialist

University of Kentucky University of Kentucky

► How a Soybean Plant Develops, Special Report No. How a Soybean Plant Develops, Special Report No. 5353

► Iowa State University PressIowa State University Press► $2.00$2.00

Extension Distribution CenterExtension Distribution Center119 Printing and Publications Building119 Printing and Publications BuildingIowa State UniversityIowa State UniversityAmes, Iowa 50011-3171 Telephone: (515) 294-5247Ames, Iowa 50011-3171 Telephone: (515) 294-5247Fax: (515) 294-2945Fax: (515) 294-2945

http://www.extension.iastate.edu/Pages/hancock/http://www.extension.iastate.edu/Pages/hancock/agriculture/soybean/bean_develop/agriculture/soybean/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 StagesVegetative Stages Reproductive StagesReproductive Stages

VE VE R1R1

VC VC R2R2

V1 V1 R3R3

V2V2 R4R4

V3V3 R5R5

V(n)V(n) R6R6

R7R7

R8R8

Vegetative StagesVegetative Stages Reproductive StagesReproductive Stages

VE – emergenceVE – emergence R1 – beginning bloomR1 – beginning bloom

VC – cotyledonVC – cotyledon R2 – full bloomR2 – full bloom

V1 – 1V1 – 1stst node node R3 – beginning podR3 – beginning pod

V2 – 2V2 – 2ndnd node node R4 – full podR4 – full pod

V3 – 3V3 – 3rdrd node node R5 – beginning seedR5 – beginning seed

V(n) – nV(n) – nthth node node R6 – full seedR6 – full seed

R7 – beginning maturityR7 – beginning maturity

R8 – full maturityR8 – full maturity

VEVE

VCVC

““Poking through”Poking through”

hypocotyl

VCVC V1V1

V2V2Rhizobia have colonized the roots.Rhizobia have colonized the roots.

N – fixation has begun.N – fixation has begun.

The roots are growing through the top 6 inches of soil.The roots are growing through the top 6 inches of soil.

V3V3

V5V5 V6V6

Axillary Buds

1)1) Form flowers that develop into podsForm flowers that develop into pods2)2) Form axillary stems, which form more axillary budsForm axillary stems, which form more axillary buds3)3) Remain dormantRemain dormant

V5V5 V6V6Apex

(Growing Point)

1)1) Dominant in vegetative growth (plant will grow Dominant in vegetative growth (plant will grow up before growing out)up before growing out)

2)2) If the apex is destroyed, the axillary buds will If the apex is destroyed, the axillary buds will produce many stems, causing the plant to “bush produce many stems, causing the plant to “bush out”.out”.

V7V7 R1R1

R2 – Full FlowerR2 – Full Flower

R2R2

R3 – Beginning podR3 – Beginning pod

R4 – Full PodR4 – Full Pod

R4 – Full PodR4 – Full Pod

R4 – Full PodR4 – 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 SeedR5 – Beginning Seed

R6 – Full SeedR6 – Full Seed

R7 – Beginning MaturityR7 – Beginning Maturity

R6R6 R8R8

Vegetative StagesVegetative Stages Reproductive StagesReproductive Stages

VE – emergenceVE – emergence R1 – beginning bloomR1 – beginning bloom

VC – cotyledonVC – cotyledon R2 – full bloomR2 – full bloom

V1 – 1V1 – 1stst node node R3 – beginning podR3 – beginning pod

V2 – 2V2 – 2ndnd node node R4 – full podR4 – full pod

V3 – 3V3 – 3rdrd node node R5 – beginning seedR5 – beginning seed

V(n) – nV(n) – nthth node node R6 – full seedR6 – full seed

R7 – beginning maturityR7 – beginning maturity

R8 – full maturityR8 – full maturity

Thank you!Thank you!