Thesis (Ph. D) - Purdue University, 1972. Tables, bibliography p. 28-29

Heterozygous opaque-2 (o2) and floury-2 (fl2) synthetic populations of maize were subjected to three cycles of recurrent selection with the selection criterion being the relative kernel weight ratio of the mutant to normal class on segregating selfed ears. Control populations were also derived from the synthetics by the same procedures but with no selection. Derived heterozygous populations were compared per se and in testcrosses using replicated field tests. Kernel weights for segregating classes were taken and relative weights ratios as percent calculated. Determinations were also made for protein content and lysine as percent of protein for the mutant kernel class of each derived population. Similar responses to the recurrent selection were found for both the o2 and fl2 heterozygous synthetics. Comparisons of derived populations indicated that relative weight ratio of the mutant to normal class had improved with selection. The improvement followed a significantly linear trend over cycles of selection and resulted from a significantly linear decrease in kernel weight of the normal class. Also, protein and lysine content of the mutant classes declined linearly with selection. In testcrosses, select populations had higher ratios of mutant to normal weights than did control populations. These positive responses resulted from increases in weights of the mutant classes.

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