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Thesis (M.S.)—University of Nebraska—Lincoln, 1963. Department of Agronomy.


Copyright 1963, the author. Used by permission.


The purpose of this study was to compare the double crosses of corn predicted from single-cross and topcross data to determine the degree of consistency of predicted double crosses from the two types of data. The study also sought to determine the importance of cross x year interactions in their effect on prediction procedures.

For the purpose of this study 12 newly developed inbred lines from different sources were used. These included recovered strains of lines commonly used in corn belt hybrids as well as those extracted from varietal and synthetic materials.

All lines were planted in paired rows in a crossing nursery at Lincoln in 1958 and the 66 possible single-cross combinations made.

In 1959, all 66 possible single-cross combinations were grown at Lincoln in a randomized complete block design with four replicating of 1 x 8 plots.

In 1960, 1961 and 1962 the single crosses were grown again at Lincoln in a randomized complete block design with four replications of the same plot size except in 1962 where only three replications were used.

It is clearly shown in this experiment that the best double crosses predicted from either single-cross or topcross data were not in good agreement from year to year.

Advisor: John H. Lonnquist