Comparison Among Sweet Corn Heterotic Patterns

Abstract

Four sweet corn (Zea mays L.) heterotic patterns have been reported among sugary1 (su1) open-pollinated cultivars: two among sweet corn cultivars (`Golden Bantam' × `Country Gentleman' and `Golden Bantam' × `Stowell's Evergreen'), one related to the `Reid' × `Lancaster' field corn heterotic pattern (`NE-HY-13A' × `NE-HY-13B'), and one related to the northern × southern Spain field corn heterotic pattern (`EPS31' × `EPS32'). The objective of this research was to compare the performance of sweet corn heterotic patterns. The four crosses and their seven parents were evaluated in 2 years, at two environments in northwestern Spain, as well as in a cold chamber. `Golden Bantam' × `Stowell's Evergreen' and `Golden Bantam' × `Country Gentleman' had poorer agronomic performance and better ear quality than `NE-HY-13A' × `NE-HY-13B' and `EPS31' × `EPS32'. `Golden Bantam' × `Stowell's Evergreen' had the best cold tolerance in the cold chamber. Earliness, emergence, and early vigor were higher for `EPS31' × `EPS32', related to the northern × southern Spain field corn heterotic pattern. Heterosis was positive and significant for several traits for `Golden Bantam' × `Stowell's Evergreen' and `Golden Bantam' × `Country Gentleman,' while heterosis was not significant for `NE-HY-13A' × `NE-HY-13B' and `EPS31' × `EPS32'. The objective of capitalizing on the `Reid' × `Lancaster' and the northern × southern Spain field corn heterotic patterns for improving sweet corn has failed. We believe that heterosis is lost when field corn heterotic patterns are combined with sweet corn, due to incompatibility in gene combination among sweet and field corn genetic backgrounds.