Genetic Variability, Correlations and Selection Response for Kernel Traits in Two Modified Endosperm Opaque-2 Maize Populations

75 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.To determine the genetics of endosperm modification and the relationships with other traits in opaque-2 (o(,2)) maize (Zea mays L.), an investigation was conducted to estimate genetic variation, correlations and responses to S(,1) family selection for kernel traits in two modified endosperm o(,2) maize populations (D.O. mod. o(,2) and El. S.C. mod. o(,2)). In 1982, 120 S(,1) families were evaluated for percent modification, kernel density, 100 kernel weight, percent protein, percent zein, percent lysine and g lysine per 100 g protein (L/P). The same kernel traits were measured in 1983 in 120 S(,2) families (four from each of 30 S(,1) families) and in 1984 on cycle 1 classes which had been divergently selected for percent modification, percent protein, percent zein, percent lysine or L/P. Heritability and genetic coefficient of variation estimates indicated progress from selection should be possible for all traits measured. Significant estimates of dominance variance based on S(,1) progeny means and S(,2) within S(,1) families in 1983 were found for percent zein, percent lysine and L/P in D.O. mod. o(,2). Additive variance was significant for 100 kernel weight, percent protein, percent lysine and L/P in El. S.C. mod. o(,2). Genetic correlations indicated efforts to maintain adequate kernel size and L/P must accompany selection for percent modification. Divergent S(,1) family selection increased the mean of the high selection class above the low for percent modification and percent protein in both populations and percent lysine in D.O. mod. o(,2) indicating selection was effective for these traits. Predicted and observed responses to S(,1) family selection were similar for most traits suggesting the heritabilities and genetic correlations were reasonable indicators of the genetic variation and relationships in the two populations. Realized correlated responses indicated yields may be increased with increasing modification.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD