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Title: COMPARISON OF MODELS FOR QUANTITATIVE TRAITS FOR F1 PERFORMANCE FROM MATING OF INBRED LINES WITH AND WITHOUT PEDIGREE INFORMATION

Author
item VAN ZYL, C. - UNIV. OF NEBRASKA-LINCOLN
item Van Vleck, Lloyd
item JOHNSON, B. - UNIV. OF NEBRASKA-LINCOLN
item SMITH, H. - PIONEER HI-BRED INT.

Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective was to compare analyses with and without numerator relationships considered of quantitative traits measured on corn as a model for analysis of crosses of fully inbred lines. Phenotypic data were for nine traits from design II matings between 28 inbred lines of each of two different heterotic groups of corn with a total of 4032 observations. In the first model lines within each heterotic group were considered random and related. This model was compared to same model without pedigree information. The second comparison was similar but with lines in first heterotic group considered as fixed in both models. The third comparison was similar to the second, but with lines in second heterotic group considered as fixed. Estimates of variance components for line effects for nine traits were obtained with derivative-free REML. Differences between models were tested with log likelihoods. All models differed significantly for all 9 traits. In the first comparison, the log likelihoods improved fo all traits after pedigree information was included. Estimates of variance among lines increased for 8 traits. When lines in the first heterotic group were considered as fixed effects in the second comparison, the log likelihood did not improve for any trait after pedigree information was included. Estimates of variance among lines decreased for all traits. When second heterotic group was considered as fixed in the third comparison, log likelihoods improved for 6 and decreased for 3 traits after pedigree information was included. Variance among lines decreased for all traits. Results suggest that pedigree information influences the estimates of variance components for line effects from crosses of inbred lines.