Sugar characteristics of sweet corn populations from a sugary enhancer breeding program

Summary

Endosperm sugars and sorbitol were determined on 18 sweet corn (Zea mays L.) populations from a breeding program undertaken to transfer the sugary enhacer (se) gene into diverse sugary (su) backgrounds. Three subpopulations of IL677a, the source of se, and six su Se inbreds were included for comparison. Mature dry kernels of between two and four successive generations of these populations were analyzed. Immature kernels at two developmental stages (21 and 35 days after pollination) were also analyzed for one generation.

Eleven of the breeding populations closely resemble IL677a, with high sucrose at the edible stage (21 days after pollination) and maltose accumulating as the seeds matured. In most instances, the distinctive sugar profiles were observed consistently in dry seeds of various generations. Hence, it appears that the se trait can be transferred successfully into su cultivars having various genetic backgrounds. The remaining seven breeding populations possessed elevated sucrose and glucose compared to most of the standard su Se inbreds, but maltose did not accumulate during seed maturation. It is not clear whether se was transferred to these populations and its expression modified or whether another trait was responsible. There were also marked differences in glucose levels among the su Se populations examined.