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Nonlinear relationship between single-cross hybrids and their parental lines
Gengchen HanI; A.R. HallauerII; T.B. Bailey, Jr.III
ICIMMYT, El Batan, Mexico
IIU.S. Department of Agriculture, Department of Agronomy, Iowa State University, Ames, Iowa 50011, USA. Send correspondence to A.R.H.
IIIDepartment of Statistics, Iows State University, Ames, Iowa 50011, USA
ABSTRACT
The relationship between single-cross hybrids and their parental lines was examined based on genetics models and sampling theory. Our objective was to develop biometric theory to explore the quantitative relation between hybrids and inbred lines. Under the assumption of no linkage and no epistasis, a nonlinear relationship between inbred lines and hybrids was found. According to this nonlinear relationship, the expected genotypic values of hybrids depend on the means of favorable loci in the parental lines, the differences between the two lines, the level of dominance, and additive gene effects. Correlations between actual and predicted hybrid values and between hybrids and midparental values were examined by computer simulation. When dominance exists, correlations between actual and predicted hybrid values were higher than those between actual hybrids and midparents It indicated that nonlinear model could predict hybrids better than that of midparents.
Keywords: nonlinear; ;single-cross; parental; lines.
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