Difficult Decisions Making Those Hybrid-Variety Selections?!

With considerable crop still standing in the field, we are already being pressured to make choices on which hybrids and varieties to grow for next season. An even more difficult decision given the abnormal season this year. Prolonged dry conditions have impacted the soybean and corn crops throughout much of the province. On top of this, we have had our first experience with the soybean aphid. Then as harvest began, abnormally wet weather, which has delayed combining significantly in most regions of the province. Data from test plots across the province continues to sit in the fields along with the crop, and won't be available for a number of weeks.

Never has the old saying "don't rely on results of single test plots" been more appropriate. Where the dry weather was most severe, the yields of corn, and especially soybeans, are well below expectation. Relying on the results from the local test plot could be a big mistake. Where yields in test plots are well below normal, cultivar rankings at these extremely low yields may change under better growing conditions. This is not to say don't use this information. However, use this information in context with results from other test plots, from areas less effected by the weather or from tests conducted in previous years. Many areas of the province that expected significant reductions in corn yields have been pleasantly surprised. Match your CHU's with these area test plot results and add this information to your "radar screen" of data when making cultivar choices.

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Research conducted by Pioneer and others over the last number of years has shown that a difference in yield between two corn hybrids of 6 bu/ac at a single location was only due to genetic differences about ~50% of the time. On a single test, the variability in soil type, fertility or any number of factors can account for yield differences between hybrids. When the same hybrids are compared at 10 locations, you can be confident ~75% of the time that a 6 bu yield difference is real and this increases to a ~90% chance of being a real hybrid difference when compared at 30 or more locations (within and/or between years). This data has been presented in many other articles but needs to be emphasized. Look at more than a single trial and local data when making decisions on variety selection!

The 1999 and 2000 growing seasons were very distinct from each other in terms of climatic conditions but the majority of the crop areas reported average to above average crop yields. Evaluating the performance of crop varieties in these two years gives a good estimation of those that have the greatest yield potential across extremes of growing seasons. Add this information to the 2001 trial data when attempting to make the right selection for your farm. New cultivars will have to be considered in light of performance trial data and other strip trial data available from areas that were not severely impacted by this past seasons dry weather.

For corn, the main benefit from severely affected areas may be identifying differences in standability between cultivars. There is a lot of lodged corn this year: pay special attention to the lodging ratings. Did hybrids that stood well in poor areas yield well in areas less affected by weather or in previous years? Those cultivars that have stood up well this year likely are good contenders for next year. Check their yield performance for the last couple of years if available. This may be helpful in deciding on which hybrids to grow.

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Soybean selection may be more difficult. Yields are poor over much of the province. We are still unsure of the ultimate impact that the soybean aphid had on yield, versus the dry conditions and high temperatures. Without extremely dry conditions, will the aphid populations be as bad? Results of various research projects here and in the US will hopefully give a clearer picture of the effects experienced. This information is needed to better determine if a similar problem will occur next year. Unfortunately, it's likely to be early in the New Year before these answers get sorted out.

Refer "ARE YOUR TRIAL RESULTS REAL?" in the September issue of CropTalk to review some thoughts on how to look at plot data. This article addresses when and if differences between cultivars in a test plot are real or not. Where check cultivars are not present in a plot, it becomes very difficult to tell if differences are real or not unless some form of statistical analysis is provided.

Sources of information for helping in variety-hybrid selection include:

Performance trial data:

• Ontario Corn Producers website
• Ontario Oil & Protein Seed Crop Committee website

Company strip trial and other data:

• various (use search engines on the web or contact local seed company representatives)

Ontario field trials on-line database

• Ontario Soil & Crop Improvement Association website

Local and regional soil and crop trials

• County & District Association, OSCIA website
• Ontario Soil & Crop Improvement Association website

Ontario Ministry of Agriculture and Food

• Crops Index Page
• OMAF Products Catalogue

Related Links

• 2001 Hybrid Corn Performance Trials, Ontario Corn Producers
• Ontario Soybean Variety Trails, Ontario Oil & Protein Seed Crop Committee
• Ontario Field Trials Online, Ontario Soil & Crop Improvement Association
• County and District Association, Ontario Soil & Crop Improvement Association
• Ontario Soil & Crop Improvement Association
• Crops Index Page, OMAFRA website
• Oil & Seed Crops Products Catalogue, OMAFRA website

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