The LEAFY (LFY) gene plays a central role in orchestrating the transition to flowering and subsequent flower development. Its functions encompass specifying floral meristem (FM) identity and floral organ fate, and regulating stem cell proliferation within flowers by transcriptionally repressing WUSCHEL (WUS), thereby establishing floral determinacy. This pivotal process is mediated by the C-class gene AGAMOUS (AG), contributing to the precise coordination of floral development in Arabidopsis (Sun and Ito, 2015). FALSIFLORA (FA), the orthologous gene to LFY, plays a role in promoting floral transition, determining FM identity and regulating floral organ identity genes (Molinero-Rosales et al., 1999; Kato et al., 2005, Olimpieri and Mazzucato, 2008). However, the role of FA in floral determinacy has so far not been addressed. In this study, we combine the screening of a tomato EMS mutant collection with CRISPR/Cas9 genome editing procedures of coding and regulatory regions to expand the FA allelic series, aimed to gain a deeper understanding of FA functional role in tomato reproductive development. Our findings unveiled the multifaceted role of FA acting in both early and late stages of floral ontogeny. Thus, we proved that FA regulates the expression of the tomato homologues of AG (TOMATO AGAMOUS1, TAG1) and WUS (SlWUS), underlying its essential role in promoting carpel development and suppressing floral stem cell activity. Taken together, our data underscore the potential of employing mutant allelic series as powerful tools for unraveling gene functions and deciphering the intricate molecular basis of biological processes.