Mapping and characterization of early flowering and brachytic3 mutants in Maize (Zea mays L.)

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Avila Bolivar, Luis M.
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University of Guelph

Early flowering is important for maize adaptation to short-season growing environments. Dwarfism, by preventing lodging, has the potential to increase grain yield. This thesis investigates three novel mutants of maize. The early flowering mutant (EarlyF) sheds pollen 1 to 5 days earlier than wild type plants. EarlyF, was shorter and developed fewer leaves than wild type plants, suggesting an earlier transition from vegetative to reproductive development. A candidate QTL for EarlyF maps to bin 7.03. The two allelic dwarf mutants, brachytic3-1 and brachytic3-2, have short internodes at maturity, resulting in severely reduced plant height. Despite being short, days to pollen shed and number of leaves were unchanged for both brachytic3-1 and brachytic3-2. brachytic3 maps to a ~ 7 Megabase region of bin 5.04. This thesis characterizes EarlyF, br3-1 and br3-2 and sets the stage for positionally cloning the mutations causing these mutants and has potential to contribute to maize improvement.

maize, genetics, brachytic, mutant, flowering time, EMS, QTL, cloning