RESPUESTA MORFOLÓGICA Y FENOLÓGICA DE MAICES NATIVOS DE TAMAULIPAS A AMBIENTES CONTRASTANTES DE MÉXICO PHENOLOGICAL AND MORPHOLOGICAL RESPONSE OF TAMAULIPAS MAIZE TO CONTRASTING ENVIRONMENTS IN MÉXICO

Introducing maize germplasm into a particular environment can increase existing genetic diversity, but this can cause phenological and morphological changes as a consequence of its inability to adapt; agronomically, this may be undesirable. The objective of this work was to determine the phenological and morphological changes in maize from different ecological regions of the state of Tamaulipas, Mexico, in environments that contrast in altitude, latitude and temperature. Four groups of native populations from Tamaulipas and two groups of improved materials were evaluated in Tropical dry, Transition, and High Valley environments. The variables studied for phenology were days to masculine and feminine flowering, floral asynchrony, and length of internodes; and for morphology the variables were plant height, number of leaves, potential grains, rows per ear, grains per row, total grains and individual grain weight. The groups of Tamaulipas populations exhibited high variability and interaction with the environment for the studied variables; besides, in Tropical dry climate they were significantly different (p £0.05) from those in Transition and High Valley climates. The group of populations from the mountainous environment of Tamaulipas had phenological and morphological behavior similar to that of the group of improved maize from the Central High Valleys of Mexico in Transition and High Valley environments. The groups from low altitude areas of Tamaulipas were later and asynchronic; plants were taller and had more leaves. The variables days to masculine and feminine flowering, internode length, total grains per ear, total number of leaves, and plant height showed significant differences among the environments evaluated; therefore they could be considered indicators of response to environmental effects on introduced populations.