This study investigated cultivar variation in biomass partitioning patterns and nutrient harvest index across eight Brassica napus cultivars (Akela, Capitol, Colosse, Naehan, Pollen, Saturnin, Sparta, and Tamra). Seed dry weight varied ranging from 5.8 ± 0.3 g DW to 35.7 ± 6.7 g DW, with Colosse showing the highest seed production and Tamra showing the lowest. Harvest index (HI) was divided two groups showing high group (Capitol, Colosse, Pollen, Tamra) and low group (Akela, Naehan, Saturnin, Sparta), which were ranged from 10.8% to 31.7%. Sulfur harvest index (SHI) ranged from 25.6% to 46.5%, with Capitol and Pollen exhibiting the highest efficiency and with Akela and Naehan exhibiting the lowest efficiency. Nitrogen harvest index (NHI) showed greater variation, ranging from 39.8% to 74.3%, with Capitol and Pollen recording the highest value but Akela and Naehan recording the lowest values. Together, these results demonstrate that seed yield, HI, and nutrient harvest index can be partially decoupled among cultivars, highlighting SHI and NHI as complementary traits for selecting nutrient-efficient rapeseed germplasm. Consequently, Colosse and Pollen emerge as promising cultivars for seed oil production, whereas Akela, Sparta, and Naehan are better suited for feed use.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Plant materials and growth conditions
    2. Biomass partitioning
    3. Sulfur and nitrogen content
    4. Harvest index calculations
    5. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
    1. Biomass Partitioning among Cultivars
    2. Sulfur harvest index
    3. Nitrogen harvest index
    4. Relationship between sulfur and nitrogen harvestindexes
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Sang-Hyun Park(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea)
• Tae-Hwan Kim(Department of Animal Science, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea, Institute of Environmentally-friendly Agriculture, Chonnam National University, Gwangju 61186, Republic of Korea)
• Bok-Rye Lee(Institute of Environmentally-friendly Agriculture, Chonnam National University, Gwangju 61186, Republic of Korea) Corresponding author