Pearl millet (Pennisetum glaucum, syn. Cenchrus americanus, 2n = 2x = 14) is a crucial cereal food and fodder crop in the semi-arid tropic dryland, yet breeding progress is slow and threatened by climate change. Speed-breeding methods that shorten generation time are established for several crops, but none exist for pearl millet or its wild relatives. We evaluated three factors pot volume, supplementary CO2, and exogenous abscisic acid (ABA) to develop a rapid-cycling protocol for cultivated P. glaucum and three wild Pennisetum species (P. mollissimum, P. violaceum, and P. schweinfurthii). Flowering occurred within 64 days from sowing in 220 cm(3) pots for P. glaucum and P. mollissimum and in 38 cm(3) pots for P. violaceum and P. schweinfurthii, enabling up to four generations per year. Supplemental CO2 increased vegetative biomass and shortened time to flowering by 14 days only for P. schweinfurthii. ABA application curtailed plant height without affecting phenology, facilitating high-density cultivation. Combining small pots with ABA permits rapid, space-efficient generation cycling across multiple Pennisetum taxa. The protocol closes a key gap in millet improvement pipelines and will accelerate introgression of stress-resilience alleles from wild relatives into elite germplasm.