title: Inflorescence development in a high-altitude annual Mexican teosinte (Poaceae).
abstract: Some have postulated that highland Mexican maize was derived from an ancient high-altitude teosinte and that later introgression between the two taxa occurred. We used scanning electron microscopy to examine the inflorescence development in both the tassel and ear of a high-altitude Toluca teosinte. One of the most interesting observations was the presence of atypical multiranked orthostiches in the central spike of some male Toluca teosinte inflorescences. Most tassels exhibited a central spike with a pure, four-ranked, tetrastichous phyllotaxy or an intermediate (distichous/tetrastichous) phyllotaxy. A few A(1) tassels had a more typical distichous (two-ranked) central spike. Most ears showed the two-rank condition expected for teosintes. However, three ears displayed an intermediate (distichous/tristichous or distichous/ tetrastichous) phyllotaxy and one ear was tetrastichous. Our analysis of spikelet and floret development in all Toluca inflorescences revealed a pattern similar to that in landrace and U.S. maize, as well as to their close relatives, the teosintes. We suggest that this investigation may reveal inflorescence development in a natural maize-teosinte hybrid. This study further supports our hypothesis that both maleness and femaleness in the Zea inflorescences are derived from a common developmental pathway and underpins a proposal that andropogonoid grasses share a common pattern of inflorescence development.
authors.affiliation: Department of Biology, University of Northern Iowa, Cedar Falls, Iowa 50614 USA;
authors.forename: Alan R
authors.initials: AR
authors.lastname: Orr
authors.forename: Kevin
authors.initials: K
authors.lastname: Mullen
authors.forename: Darcey
authors.initials: D
authors.lastname: Klaahsen
authors.forename: Marshall D
authors.initials: MD
authors.lastname: Sundberg