The grass family (Poaceae) is economically the most important plant family, being the source of cereal grains such as wheat, corn, rice, barley, sorghum, and millets. Sugar cane and lawn grasses are also members of this family. In addition, grasses constitute the fourth largest flowering plant family and comprise over one-fourth of the world's vegetation. Unfortunately, the phylogeny (genealogy) of this family is merely speculative; numerous groups such as genera and tribes are still unclassified, and the boundaries and naturalness of several tribes are questionable. These difficulties arise from the extreme reduction and consequently limited usage of grass floral morphology in classification and suspected parallel evolution where two unrelated species superficially look alike becasue of adaptations to the same environment. Drs. Hilu and Esen of Virginia Polytechnic Institute will be using the molecular size and immunological properties of a class of storage proteins called prolamins as a measure of genetic distance between various groups of grasses. The prolamins are found only in grasses and are known to be little affected by environmental conditions. When these virtues are combined with refined molecular methodologies, the P.I.s have an effective approach for assessing the genomic relationships between various groups of grasses. Preliminary work on representative grass genera using prolamins clearly demonstrates the far-reaching applications of this molecular approach. The potential impact of the research is two-fold. First, it will increase our understanding of the biology of this large and important plant family. Second, since all of the cereal grains will be included, this study will help to define the gene pool of grasses that can be used in improved breeding of cereal crops.
