Maize Introgression Into Teosinte-A Reappraisal

neidered Maize (Zea mays L. subsp.mays) and its wild relativ: by many authors t to be undergoing substantial reciprocal introgression.While 'there is evidence that has been largely circumstantial.A re-consideration of th id f gr te e proved it wanting.Red sheath color, large grain size, triangular fruitcase -and the presence of internal chromosome knobs, all characters attributed to maize introgression into teosinte, appear rather to reflect the adaptation of particular teosinte populations to the exigencies of specific ie ei Apparently, the taxa of teosinte have remained relatively free of Het inti maize contamination at from maize to teosinte, although possible, remains undocumented.Introgressive hybridization, or more simply, introgression, is the incorporation of genes from one population into another with a different adaptive norm rson & Hubricht, 1938).This process is of obvious importance to taxonomists and evolutionists because, along with mutation, gene drift, and recombination, it is a potential source of evolutionary variation within and among species.Introgression is of particular interest to scientists studying cultigens апа their y lack barriers to hybridization and they often grow sympatrically.For these reasons, one would expect introgression between crop species and their ancestors to occur with some frequency.The cultigen maize (Zea mays L. subsp.mays) and its wild relatives, the teosintes, have been considered model examples of reciprocal introgression (de Wet & Harlan, 1972;Heiser, 1973; Wilkes, 1977).The evidence for teosinte ind ere farmers in Mexico encourage the hybridization of teo-'Tam arces to H. H. Iltis, R. R. Kowal, D. M. Waller, W. C.