A maternal effect influencing DNA endoreduplication activity in the developing endosperm of maize has been observed in data generated by flow cytometric techniques. The overall objective of this project is to expand the information concerning these maternal effects in the developing endosperm. Specifically, tests will be made to determine: (1) the extent of the maternal effects in reciprocal crosses among a wide range of inbreds; (2) the precise characteristic(s) that are governed by the maternal effects; and (3) the role of these maternal effects in the cytokinetics of the developing endosperm. Flow cytometric analyses of endosperm will be obtained from a diallel pattern of parents and F1 reciprocal crosses at the peak of endoreduplication activity and at closely spaced intervals over an extended developmental period. Brd/Urd/monoclonal antibody techniques in conjunction with an in vitro ear culture system will be used to determine the role of maternal effects upon cell cycle phases and DNA replication rates. The information could lead to new ideas about DNA replication, cell cycle timing, genome interaction, and even combining ability and hybrid vigor. The possibility exists that such information might eventually be used in a predictive manner for the selection of parents for hybridization.
