Photoperiodic flowering in field crops: Mechanisms and the link to abiotic stresses

Flowering, the developmental transition from vegetative growth to reproductive phase, represents a critical life cycle switch that determines crop reproductive success and yield potential. However, this process is concurrently modulated by a multilayered regulatory network incorporating photoperiods, phytohormones, and stress responses, enabling plants to integrate multiple signaling inputs. This review systematically examines the molecular architecture of flowering time regulation, with particular emphasis on: (1) the photoperiod-circadian clock nexus in the model plant A. thaliana; (2) evolutionary adaptations of these pathways in field crops (rice, soybean, and other field species); and (3) emerging mechanisms of stress-induced flowering under abiotic challenges. Through comparative analysis of conserved and divergent molecular strategies between model plants and field crops, we highlight key regulatory nodes - including the CO-FT photoperiodic module and its interaction with vernalization, age, and hormonal pathways - that have been targeted during domestication. We further propose innovative breeding strategies leveraging CRISPR-based pathway engineering, multi-omics network analysis, and synthetic biology approaches to optimize flowering time plasticity for climate-resilient agriculture. • Photoperiod influences flowering time and crops yields through its interaction with exogenous light signals and endogenous circadian clock. • The CO-FT module of Arabidopsis thaliana provides a model system to understand photoperiodic flowering in other crops. • The crosstalk between GA and other phytohormones signaling pathways work together with photoperiod in the regulation of flowering. • The exploitation of flowering trait can lead to improvement of field crops as the distribution of rice and soybean at wide range of latitudes occurred due to evolution of flowering trait. • Circadian clock interacts with photoperiod pathway to maintain plant growth response against different abiotic stresses (heat, drought and salinity).