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Title:Farmers' expectations of yield differences between triple-stack and conventional corn hybrids
Author(s):Ubbenga, Krista J.
Advisor(s):Schnitkey, Gary D.
Contributor(s):Schnitkey, Gary D.
Department / Program:Agr & Consumer Economics
Discipline:Agr & Consumer Economics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):Corn
Triple-Stack
Trait
Hybrid
Yield
University of Illinois
Farmer Perception
Survey
Interview
Test-Trial
Data
Abstract:In 1996, genetically modified corn was commercially available for the first time. Since then, seed technology companies have introduced new genetically modified hybrids, including ―stacked trait hybrids‖ containing multiple traits. Adoption rates of the genetically modified seed increased for several years and the technology is now widely accepted in the United States. Willingness to adopt a new technology is based on the belief that it is an improvement over current practices. Seemingly, a triple-stack corn hybrid (a hybrid containing three genes) should provide a higher net return than a hybrid with fewer genetic traits. Dramatic farmer adoption rates of triple-stack corn hybrids could suggest that farmers believe that the added traits will improve hybrid performance. On the other hand, farmers must also choose seed from the selection available, consisting mostly of hybrids with a triple-stack trait package. Previous studies comparing transgenic yields to non-transgenic yield have mixed results. However, the literature reviewed suggests that farmers believe that there is a yield advantage associated with triple-stack corn hybrids. Therefore, the hypothesis is developed that farmers‘ subjective estimates of triple-stack corn yields will be above the yields found in the objective data. Three goals are set to test this hypothesis: 1) determine the effect that traits in hybrids have on corn yields, specifically the effect of triple-stack traits on corn yields; 2) determine what farmer perceptions of triple-stack hybrid yields are; and 3) compare the triple-stack objective yield data to farmer perceptions. The objective data are from the University of Illinois corn hybrid test trials from 2004-2008. Hybrids are assessed based on the traits present and regression models are used to test for statistical differences in yields between hybrids with varying traits. Personal interviews conducted with eight farmers located across Illinois in August, 2009, and a survey distributed to 65 Farm Business Farm Management Association cooperators in September, 2009, are used as proxies for farmer perception; the results from both are used as subjective data in the study. The objective yield data shows that the traits for corn borer resistance and root worm resistance both significantly increase yield by approximately 2 and 4 bushels per acre, respectively. A trait for herbicide tolerance was not found to make a significant difference in yield. Triple-stack hybrids, containing all three traits, have a yield advantage of 6-7 bushels per acre. In the interviews, farmers indicated a value in triple-stack corn hybrids, but much of that value is due to advantages other than yield. Farmers who pinpointed a range for triple-stack yield advantage over refuge hybrids, selected ranges beginning at 7 bushels per acre and going up to 15 bushels per acre. Based on weighted averages of the responses from farmers who selected a specific range in the survey, the farmers who plant triple-stack hybrids believe triple-stack yields are 9.45 bushels per acre higher than refuge and the farmers who do not plant triple-stack hybrids believe triple-stack hybrids yield 5.87 bushels per acre higher than refuge. A conclusion is reached that farmers‘ yield assessments are fairly accurate. Farmers that plant triple-stack hybrids perceive a triple-stack yield advantage that is slightly higher than the value found in the objective data, although some did not provide a specific range. Interestingly, 23% of farmers planting triple-stack hybrids believe triple-stack and refuge yields are the same.
Issue Date:2010-01-06
URI:http://hdl.handle.net/2142/14729
Rights Information:Copyright 2009 Krista Joy Ubbenga
Date Available in IDEALS:2010-01-06
2012-01-07
Date Deposited:December 2


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