9801450 Doebley The phenomenal diversity of the grass tribe Andropogoneae, which contains such common plants as corn and prairie grass, will be examined in this study. This group provides material to elucidate the molecular and genetic changes that has led to the evolution of variable forms. There is good evidence that the tribe originated about 60 million years ago, and since that time members have diverged so that genera display a dazzling array of both floral and vegetative characteristics. The hypothesis that changes in the same gene underlie the evolution of related but diverse traits will be tested using the gene teosinte branched1. In maize tb1 is involved in the control of stem branching and floral-gender aspects of plant and inflorescence architecture. Utilizing in situ hybridization of selected organs of different genera, we will begin to determine if tb1 expression patterns correlate with the observed pattern of trait diversification across the tribe. If such a correlation exists, we will have evidence that a single gene can potentially contribute to the evolution of a specific morphological feature.