Abstract: To study the influence of geographical metrological factors on the dynamic accumulation of oil content in developing seeds of Brassica napus, we grew 2 high-oil-content lines, XZ37 (oil content: 45.29%) and XZ366 (oil content: 43.48%), at 3 distinct geographical locations in Nanjing, Xining and Lhasa. We recorded the accumulation rate of oil in developing seeds, and metrological data such as daily mean temperature (DMT), sunshine hours (DMSH) and precipitation (DMP) were obtained from a local metrological observatory. Dynamic accumulation of oil in developing seeds differed greatly among the 3 geological locations. At Xining, oil began to rapidly accumulate in developing seeds at 19 days after flowering (DAF) and lasted for about 15 days. It began to accumulate at 29 DAF at Lhasa and 24 DAF at Nanjing, for 20 and 15 days, respectively. Oil accumulation rate was positively correlated with DMT and DMT difference (DMTD) and negatively with DMP. DMT and DMSH were the major climatic factors affecting oil accumulation in developing seeds at Nanjing, where the daily temperature continued to increase after flowering until seed maturation and resulted in low oil content. DMT and DMP mainly affected oil accumulation at Lhasa, and DMTD and DMP mainly affected oil accumulation at Xining. Higher seed oil content at Xining and Lhasa than Nanjing resulted from larger DMT covering the stage after seed development. However, oil accumulation was lower at Lhasa than Xining because of increased DMP and reduced DMT. High DMT, then increased DMTD and low DMP, can benefit oil accumulation during seed development in B. napus.

Key words: Brassica napus, meteorological factor, seed development, oil content