Cereal Chem 52:115 - 118.  |  VIEW ARTICLE
A Note on the Correlation Between Lysine and Tryptophan Content in Maize Kernel Endosperms.

H. O. Gevers. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

In maize kernel endosperm populations segregating for the opaque-2 (high-lysine) mutant, the correlation between the lysine and tryptophan content is positive and highly significant in mixed kernel samples. However, in samples restricted to either opaque-2 or normal endosperm types, the strength of this association is invariably reduced as indicated by correlation and regression coefficients. This anomaly arises from the fact that in respect to lysine and tryptophan content the opaque-2 mutant separates segregating populations into high and low subpopulations presumably with distinct means and variances, thus invalidating the correlations and regressions based on mixed kernel samples. The regression of lysine on tryptophan (as an indirect screening method for lysine content) is therefore incorrectly based if done on mixed kernel data and considerably reduced if based on pure kernel types. Critical comparisons and evaluations should therefore be based on more accurate and direct analytical methods.