Post on 17-Jun-2020
Selecting Soybean Varieties for Maturity
Bill WieboldPlant SciencesUniversity of Missouri
As the earth revolves around the sun, length of photoperiod changes each day.Length of photoperiod is related to latitude.
23.5°Earth is tilted on its axis
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Length of Photoperiods as Affected by Date
Vernal Equinox Autumnal Equinox
Summer Solstice
Winter Solstice Winter Solstice
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Length of Photoperiods as Affected by Latitude
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Sikeston Maryville
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Photoperiod Length in Missouri
23 minutes
Iowa State University
Photoperiod/dark period sensed by a chemical in the leaves. So, leaves are necessary to induce flowering
Inducing signal is from leaf to bud at the nodes
Temperature interacts with photoperiod (dark period) to regulate soybean flowering and maturity
Scott and Aldrich, 1970
Logic for Selection of Maturity Group
Soybean yield is product of number of days of seed filling and the rate at which seeds fill
Vegetative growth before and after flowering begins builds photosynthesis factory; more leaves greater rate of seed fill
Later maturing varieties will produce more leaves before flowering starts
Later maturing varieties will possess greater number of days for seed-filling
Later maturing varieties may have faster rate of fill for more days, so may yield more
Project to Study Ultra Early Soybean Maturity
2 years: 2005, 20063 locations: Columbia, Albany, Portageville4 maturity groups: III, IV, V in Columbia3 varieties in each maturity group3 planting dates: mid-April, mid-May, mid-June
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mid-April mid-May
III IV V
Soybean Yield for Four Maturity Groupsaverage of 2 years and 3 varieties
Portageville, MO
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Two years: 2013 and 201410 southern locations including Columbia, MOFour maturity groups: III, IV, V, VIFour varieties within each MG: seven brands represented for the 16 varietiesFour planting dates: Late April, Mid May, Early June, Late June (DC)Funded by Mid-South Soybean Board & MSMC
Project to determine effect of maturity group on soybean yield
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Soybean Yield for Four Maturity Groupsaverage of 2 years and 4 varieties
Late April PD, Portageville, MO, Vories & Shannon
MU Variety Testing Program
4 regions: North, Central, Southwest, SoutheastEntries separated into two maturity groups in each regionMG III and IV in North and CentralMG IV and V in Southwest and Southeast
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Average Yields for all MG III and MG IV Varieties Entered in MU Variety Testing Program
Average of 5 locations in Southeast Region
Average Yields for Groups of MG IV and MG V Varieties Entered in MU Variety Testing Program
Average of 5 locations in Southeast Region
All varieties58.056.03.6%
Top 3 varieties65.662.64.8%
Top 1 variety66.863.65.0%
MG IVMG VAdv IV
Varieties differ for yield potential, but that yield difference is not related to maturity group (if not widely unadapted).
Opens up additional variety choices.
In some regions, selecting varieties with a range of maturities may add yield stability.
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Proposed Maturity Group BoundariesMourtzinis, Gaska, and Conley
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Double Cropping and Other Late Planted Situations
Shorter growing season, especially in north range of where double cropping is feasible
Plants induced to flower almost immediately after emergence
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Soybean Yield for Four Maturity Groupsaverage of 2 years and 4 varieties
Mid-June PD, Portageville, MO, Vories & Shannon
Use “normal” maturity for region
If planting delayed to ultra late, maybe earlier ½
Increase seeding rate
Selecting Soybean Varieties for Maturity
Bill WieboldPlant SciencesUniversity of Missouri
New “Missouri Soybean Center”soybeancenter.missouri.edu