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Three Steps to Interpreting Yield Information for Seed Selection

November 3, 2018
This agronomic image shows corn harvest

After the hard work of harvest is over, it’s time to begin locking in which seeds to plant next year. To help you decide, it’s important to understand what yield information to use strategically in planning.

Step 1: Compare Correct Yield information

Yield results are widely available from multiple sources. Whether the data comes from a local field trial or from multiple locations over several years, farmers need to be sure the matchup is fair. Keep the following factors in mind when evaluating results:

  • Relative Maturity (RM) – Relative maturity is a predictor of how many growing days a hybrid will require to reach maturity. Yield is often maximized by planting the fullest-season hybrid adaptable to a specific growing region. The best yield comparisons will result from comparing hybrids with a similar RM.
  • Moisture Content – Another way to guarantee you are comparing similar RM hybrids without having to research that information is to observe moisture content differences between the hybrids being compared. NK® seeds limit all comparisons to + or – 3% moisture difference for corn and + or – 2% moisture difference for soybeans.
  • Trait Package – It is important to only compare hybrids with similar traits or insect control options. There is likely going to be a yield difference between insect control-traited hybrids compared to non-traited hybrids. It can be misleading to compare hybrids that do not have similar trait offerings.

Step 2: Seek Accurate Data

It is not uncommon to receive a copy of yield results from the trial harvested a few miles down the road.  Over time, such results start to stack up and questions arise. The highest-yielding hybrid at one plot may be the lowest-yielding hybrid in another, or there may be hybrids in one plot that aren’t in another. Different data can be interpreted in many ways; be sure you’re looking at what’s best for your fields.

  • Paired comparisons – a head-to-head measure of 2 hybrids across multiple locations, are usually the simplest way of looking at and interpreting such data.

Multiple locations, from over several years if possible, improve the odds of predicting the right hybrid, either because it is higher-yielding or it is better-adapted. This provides a more accurate prediction of the hybrid/variety that will provide the best performance in varying environments as a growing location.

  • Least Significant Difference (LSD) – a statistic that takes into account the error in a trial and helps show whether one hybrid/variety is actually outperforming another. It is the minimum yield difference between 2 hybrids needed before one can be confident there is a yield difference.

LSD is strongly influenced by the number of locations used to measure the difference between 2 hybrids. It is usually lowered as the number of locations increases. Lower LSD indicates less error in the trial results.

  • Probability – the likelihood of a result occurring when repeated over time.
  • The probability of identifying the best yielding hybrid goes down as the number of entries increases.
  • The probability of identifying the best yielding hybrid goes up as the number of locations increases.

Step 3: Gather Enough Information

Determining the amount of information needed to make seed decisions is a delicate balancing act. It is important to get data from multiple locations which represent your growing conditions. It is also desirable to have multiple-year data sources. Together, these variables can provide very high levels of confidence in decisions.

Having the “top” hybrids/varieties may seem important, but a hybrid on top in one trial may be in the middle of the next. It is important to look for hybrids that are consistently among the top performing across locations. It is also critical to understand how a hybrid/variety will fit on your field. Does it have the desirable agronomics, match producer practices, have the right trait technology, etc. – all factors that your local NK agronomist can help with when selecting the right hybrid/variety for your fields.

Find NK yield results online.

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All photos are either the property of Syngenta or are used with permission.