Variation of the pleiotropy effect in a changed genetic background, demonstrated with barley mutants

In a series of experiments the independent variation of individual characters of the pleiotropy complex is demonstrated. Separation of agronomic characters from undesirable ones is also possible. Moreover, the mode of inheritance of the individual features of the pleiotropy syndrome is studied when the macro-mutants have been crossed with three unrelated varieties. The studies result in information about the suitability of the parents to modify the single traits. There is a clear relationship for the difference between the parents for the character culm length, quantity of variance, and number of modified mutants selected in the F2. This relationship is less pronounced for spike-internode length. In the present experiments, it is not possible to predict whether a cross will yield many or only a few plants with modified spike density. (author)