161 pages ; Hemp (Cannabis sativa <0.3% tetrahydrocannabinol, THC) is a crop with great potential, but historical blanket bans on C. sativa have meant that knowledge and tools are lacking for breeding and production. With the recent legalization of hemp, there has been a wave of interest in the crop, but basic questions about the plant still remain. In this dissertation, data and tools relevant to hemp breeding and production are presented, including an overview of the crop, available genetic tools, and applicable breeding concepts. I describe the development and application of tools to distinguish cannabinoid chemotype and plant sex. The utility of these tools was shown in a marker assisted selection scheme leading to a new cultivar and the determination that a plant with two Y chromosomes and no X chromosomes is likely inviable. A time course analysis of cannabinoid production throughout the course of flowering under several biotic and abiotic stresses was conducted, leading to the somewhat surprising result that in high cannabidiol (CBD) cultivars, the CBD:THC ratio was essentially fixed, information with major importance for CBD production. Finally, I examined the genetics of flowering time and mapped two major flowering time loci on Chromosome 1, named Autoflower1 and Early1. I also analyzed accessions that were induced to flower under continuous light, which suggests the presence of multiple genes controlling photoperiod insensitivity in C. sativa germplasm. Possible extensions of this work, some of which are ongoing projects of the Cornell Hemp Breeding team, are discussed. Overall, this work provides useful data for future hemp breeding efforts and high-throughput molecular tools to facilitate breeding.