Variety Testing: A Guide for Seed Choice

Ellen Phillips, Extension Educator, Countryside Extension Center, 708-352-0109, ephillps@uiuc.edu

As farmers begin planning for 2004, University of Illinois variety trials can help guide them in making their seed selection. These trails offer yield information over a wide range of soils and climatic conditions. While reviewing one year’s data provides sound information, studying several years’ data at different locations is better. Each testing site also provides inherent variability in soil types, harvesting conditions, timeliness of and amount of rain, etc. Different environmental conditions can affect the seed being tested. Variety differences can reflect how well hybrids can yield even in stressful environments. If a hybrid consistently out yields others at different test locations and different years, it indicates a good variety and should be considered.

In the 2003 Variety Trials, there were 370 corn hybrid entries from 51 different seed companies that were tested at 12 sites. There were 134 conventional soybean varieties and 661 Roundup-resistant varieties tested at 13 different sites throughout Illinois Regional corn yield averages in northern, west central and east central trials were over 200 bushels per acre. Soybean yields were much lower than normal due a hot, dry August as well as pressure from disease and insect pests.

When evaluating the yield results also look at the moisture level in the grain when they were harvested. Different moisture levels can be found between early, medium and late varieties. Two hybrids might be planted and harvested on the same date, yet the medium season variety might have 15 percent moisture while the full season hybrid may have 19 percent moisture at harvest. The additional drying requirements or yield losses, if field dried, may result in greater profit losses. Grain moisture, percentage of erect plants, oil and protein content, and plant population data are included in the University of Illinois Variety Trail information. When comparing soybean varieties look at maturity, lodging and plant height. Equally valuable is to evaluate the disease resistance of the hybrid or variety.

Using statistical tests to compare varieties can be a useful tool. University of Illinois Variety data lists the Least Significant Difference (L.S.D) from the trails. To compare two hybrids or varieties, calculate the difference between them, if it is greater than the tabulated L.S.D. value, the hybrids or varieties are assumed to be significantly different.

Copies of the University of Illinois Variety Trial results are available at Extension offices and at the website: http://vt.cropsci.uiuc.edu/.