Short Growth Duration in Brassica napus L.: Physiological and Ecological Bases, Genetic Regulation, Trait Trade-Offs, and Breeding Perspectives

Rapeseed (Brassica napus L.) is a major edible-oil crop worldwide. Its growing season is increasingly constrained by intensive cropping systems, especially the rice–rapeseed rotations that dominate the Yangtze River basin of China. Short growth duration refers to a shorter interval from sowing to maturity, which allows rapeseed to fit these narrow rotation windows and to expand the use of winter-fallow farmland. Under the same sowing date, early maturity results in a shorter growth duration. Growth duration reflects several developmental stages, yet most studies have focused on flowering time. It only partly predicts maturity and reveals little about trade-offs with yield, quality, or stress resistance. Here, we synthesize the physiological and ecological regulation of short growth duration and the genetic loci controlling successive developmental phases, including vegetative growth, the floral transition, flowering, and silique maturation. A key challenge is to combine short growth duration with high yield, good quality, and stress resistance. We examine genome-wide co-localization of growth-duration loci with loci for these traits and identify shared candidate genes. As an empirical test, we also analyze the phenotypic performance of 99 lines from the early-maturity group of the 2021–2025 Chinese National Winter Rapeseed Regional Trials. Future work should resolve links between maturity and other traits to guide selection for suitable growth duration while preserving better yield, quality, and stress resistance.