Understanding the 2015 Western Manitoba Soybean Adaptation Trial Table

The Western Manitoba Soybean Adaptation Trial table combines elements of both long term data and single site year data.

You start by using the long term data listed on the left half of the table to assemble a short list of varieties. Information includes Company Maturity Grouping, Variety Name, Yield % Check, Site Years Tested and Relative Days to Maturity +/- of Check. As you go down the table you will see that varieties are listed from earliest maturing near the top to later maturing near the bottom based on Relative Days to Maturity +/- of Check (23-10RY).  The Yield % Check and Site Years Tested should be used together when comparing the varieties.  The Site Years Tested represents the total number of locations a particular variety has been tested and the Yield % Check represents the yields of those varieties based on the number locations tested.

The right half of the table includes the 2015 Yield % of 23-10RY for five individual Western Manitoba sites and can help you refine your variety short list.  To assess real yield differences between any two varieties within a location using this table, start by looking at the LSD% at the bottom of the table. The LSD (Least Significant Difference) is the minimum difference required between any two varieties compared at the same site. For example, the LSD% for the Boissevain is 9% and yield for the check variety (23-10RY) has been set at 100%. Only varieties that yielded 109% or greater would be considered higher yielding than the check and only varieties that yielded 91% or less would be considered lower yielding than the check. Any other varieties are considered to be yielding the same as the check. We are not restricted to only comparisons with the check variety when using this single site year data.  Yield comparisons can be made between any two varieties at the same site using the LSD% for that site.  Caution should used when making variety decisions based on one year’s data. Using the long term data listed on the left half of the table will give you a better feel for how a variety performs over multiple site years.

Submitted by Dennis Lange, FPE Altona and Terry Buss, FPE Beausejour

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