Brassica napus Transcriptome or Gene expression
Rapeseed production involves significant labor demands, high concentration, and strong seasonality. Canada and the United States often utilize partial harvesting methods, while Germany primarily employs combine harvesting. According to a survey, in 2013, 60% of rapeseed in the Yangtze River Basin was mechanically harvested using partial methods, while combine methods accounted for 40%. Still, debate continues over which harvesting method better suits rapeseed in China. This experiment took place from September 2018 to May 2019 at the Xiangyang Agricultural Science Research Institute in Hubei Province. The test material used was Zhongshuang 11, which has an oil content of 49.04% and was developed by the Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences. Combine harvesting commenced 23 days post-anthesis, with a harvest every 3 days until 47 days post-anthesis, designated as CK1 through CK9. In total, 9 treatments with 3 repetitions each were applied. Two-stage harvesting simulated mechanical methods, starting with manually cutting 10 cm above ground and subsequently threshing after a designated ripening period. The first treatment was cut 21 days post-anthesis, labeled as D1, with subsequent harvests recorded as L3, L6, and so forth until day 12. The second treatment was cut 29 days post-anthesis and labeled as D2; the third treatment was cut on day 35 and labeled as D3, following the same ripening intervals for labeling. This study focuses on the differences in total flavonoids, polyphenols, carotenoids, anthocyanins, proanthocyanidins, chlorophyll, and other secondary metabolites in rapeseed, alongside its antioxidant properties and microstructural features, influenced by various cutting times for both combine and two-stage harvesting. Additionally, this research utilizes transcriptome and metabolome analyses to investigate the underlying mechanisms of the harvesting methods. Based on findings, optimal timings for combine and partial harvests to achieve the highest quality rapeseed will be recommended.