The phase transition period from vegetative juvenile to reproductive stage in Citrus is a lengthy process lasting anywhere from 2 to 15 years. During this long transition period flowering is suppressed. TERMINAL FLOWER1 (TFL1) likely plays a role in this process by repressing flowering promoting genes such as APETALA1 and LEAFY. The overexpression of Citrus sinensis TFL1 (CsTFL1) in Arabidopsis suppressed flowering promoting genes in transgenic Arabidopsis lines, however, the function of CsTFL1 in Citrus is yet to be characterized. In other tree crops such as apple, knocking out MdTFL1.1 gene function by CRISPR-Cas9 results in an early flowering phenotype. In this study, I will use CRISPR-Cas9 to knockout CsTFL1 in sweet orange (C. sinensis), a well-known commercial Citrus variety. Additionally, I will use intron-specific hairpin RNAi methodologies to silence CsTFL1 to compare the phenotypic effect of these two procedures. By exploring the role of CsTFL1 in Citrus, my project aims to reduce the long juvenile period of commercial Citrus varieties to accelerate the citrus breeding process.