Michigan State University Extension
Michigan Soybean Information - 00000001
11/16/00
Soybean Growth and Development
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The soybean plant is highly sensitive to its environment.
The total growth and yield of the crop may vary widely
depending upon location, soil, planting date, variety
selection, weed competition, diseases, pest injury,
fertility levels, etc. (Vis. 1)This level of
environmental sensitivity often varies according to the
particular growth stage of the crop. Therefore, careful
manipulation of these factors and good troubleshooting
techniques are necessary to get top yields and profits.
This requires a good understanding of how the plant grows
and develops.
Development
Development of the soybean plant begins at germination
and ends when the mature seed is ready for harvest. The
plant's total growth and lifespan, including length of
vegetative growth, time of flowering, and maturity, are
greatly influenced by photoperiod and day-night
temperatures. The photoperiod sensitivity trait is
especially noteworthy since diurnal day-night length
relationships vary widely from north to south. Most
varieties have a "critical threshold" night length
requirement for floral initiation and development.
Plants grow vegetatively during periods with shorter
nights, and start reproductive development when nights
exceed the critical threshold length. Thus, a variety
with a short night length requirement flowers and matures
earlier than varieties with long night length
requirements.
Generally, there are four maturity classes planted in
Michigan(Vis. 2). These are designated 0, I, II and III
with the predominate acreage being Group I and II. Those
varieties of the earliest maturity have a shorter night
length requirement for flower initiation and are thus
adapted to the northern areas where nights are shorter
during the growing season. Varieties adapted to southern
latitudes will normally grow taller and mature later than
normal when planted in northern latitudes. Varieties
adapted to northern latitudes will normally be shorter
and mature earlier than normal when planted in southern
latitudes.
In addition, the amount of vegetative growth before
flowering depends on the variety and environment. The
amount of vegetative growth occurring after flower
initiation depends on both environment and growth habit,
which may be determinate, or indeterminate.
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
This file was generated from data base S1 on 11/16/00.
Data base S1 was last revised on 11/16/00.
For more information about this data base or its contents please contact
reinholt@michigansoybean.org . Please read our
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