The isolation and characterization of the gene(s) associated with and potentially responsible for the regulation of apomixis (asexual) and sexual reproduction in the grass species Tripsacum dactyloides is quintessential to agricultural advancement. Apomixis is the mechanism by which plants can produce seed without fertilization, where all progeny are genetically identical to the maternal parent. In natural populations of the genus Tripsacum, lower ploidy forms (i.e., diploid, 2n=36) reproduce sexually and the higher ploidy forms (triploid, 3n=54; tetraploid, 4n=72; etc.) reproduce asexually via apomixis. In order to gain a better understanding of sexual reproductive processes in plants, subtractive hybridization was performed on early and late female inflorescence gene products. This procedure allows for the recovery of gene products in the form of complimentary DNA, cDNA molecules, which correspond to messenger RNA (mRNA) present. These cDNA molecules were then used to extract unique sequence messages from the early developmental stage ovule tissue of diploid T. dactyloides. These cDNA molecules will allow for the direct isolation of the original form of the gene(s) from a large fragment library of the Tripsacum genome. Isolation and characterization of these gene(s) is of pivotal importance to our understanding of alternate modes of reproduction in Tripsacum. / Department of Biology