Rapeseed (Brassica napus L.) is typically grown under field conditions in Korea, with one generation per year, and requires 6-7 years to develop homozygous lines. This study established generation-acceleration protocols for different rapeseed growth types by combining speed breeding (SB) and speed vernalization (SV) and evaluated their applicability to Korean-bred cultivars and lines. Under SB (22 h light/2 h dark), the spring and semi-winter types flowered at 33 and 43 days after sowing, respectively, whereas bolting was not observed in the winter-type. In contrast, the winter-type flowered after SV at 10℃ for 2 weeks under an extended photoperiod (22 h light/2 h dark), followed by transfer to SB conditions (SV(2)-SB). For all three types, pods were harvested 45 days after flowering, and seed germination exceeded 95%. Accordingly, the spring and semi-winter types achieved four generations per year under SB, whereas the winter type achieved three generations per year under SV(2). When applied to Korean-bred cultivars and lines, SB induced flowering in all accessions and most seeds germinated (>90%), enabling four generations per year. However, no seed set was obtained in one cultivar (‘Yuryeo’), indicating that further optimization is needed to ensure reliable seed production under generationacceleration conditions. Overall, these protocols account for growth-type-dependent vernalization requirements and provide a foundation for shortening the rapeseed breeding cycle, with the flowering response and white-flower phenotype as practical selection indicators.
The F1 hybrid rapeseed (Brassica napus L.) exploits heterosis to deliver greater yield, stability, and uniformity than open-pollinated cultivars, making it suitable for large- scale cultivation. In Korea, cultivation is shifting from landscape and apiculture to expanding edible oil production and increasing the demand for paddy field-adapted hybrids. Using Mokpo-CGMS as the female and the pollen parent ‘09003-B-126-2-1-3,’ we developed the breeding line ‘Dangyo 80,’ which, after multi-environment evaluations of yield and oil quality against ‘Sunmang,’ was selected as a new cultivar ‘Areum. ’ ‘Areum’ exhibits growth habit type IV, yellow flowers, and a red seed coat. Its flowering and maturity times are comparable to ‘Sunmang. ’ Major growth indices did not differ significantly among cultivars; however, while ‘Areum’ showed slightly greater lodging susceptibility, it displayed higher resistance to Sclerotinia stem rot. Notably, in paddy fields ‘Areum’ achieved a higher plant density per square meter than ‘Sunmang’ which produced a 31% yield increase. In fatty acid composition, ‘Areum’ had higher oleic acid content (65% vs. 60%) and lower erucic acid (0.95% vs. 1.35%) than ‘Sunmang,’ indicating improved suitability for high-quality edible rapeseed oil production (Registration No. 9755).