Time to flowering and flowering duration in mungbean are unrelated physiological traits with independent genetic controls

Mungbean (Vigna radiata), a valuable sub-tropical grain legume, typically has a long, asynchronous flowering window, which increases vulnerability to abiotic stress and complicates harvesting. To facilitate breeding efforts, we conducted an extensive study of days to flowering (DTF) and the novel trait flowering duration (FD) in multi-environment trials. A diverse nested association mapping population was evaluated across four field trials in Queensland, Australia. Extensive phenotypic variation was observed for both DTF (35–70 d after sowing) and FD (20–60 d). Both traits displayed Genotype × Environment interactions, with FD showing stronger environmental interactions than DTF. No relationship was evident between DTF and FD across environments. Genome-wide association studies identified eight quantitative trait loci (QTLs) for DTF and one for FD, with none overlapping. The accumulation of early or late alleles at DTF QTLs was associated with variations in flowering time. These results show for the first time in mungbean that DTF and FD are independent traits with distinct genetic controls and environmental responses, providing a mechanistic understanding of how flowering patterns may be optimised to potentially enhance adaptation and performance in diverse agricultural environments challenged by climate change.