This study was conducted to investigate the changes in seed productivity of Italian ryegrass (Lolium multiflorum Lam.) according to harvest time after heading in a mountainous area of Gangwon Province. The Italian ryegrass variety ‘Greencall’ was sown in the fall of 2021 in the Pyeongchang region of Gangwon and harvesting was performed every 10 days from 30 to 60 days after heading.. The treatments consisted of four seed harvest times (30, 40, 50, and 60 days after heading), arranged in a randomized complete block design with three replications. Plant height reached its maximum (93.0 cm) at 30 days after heading and subsequently declined with delayed harvest. Lodging resistance, disease resistance, and winter hardiness did not differ significantly among treatments, but lodging became more severe with time (rated 8∼9). Diseases were also more prevalent in the plots harvested 50 and 60 days after heading. The length of the spike was longest at 40 days after heading (54.33 cm), while the number of seeds per spike was lowest in the 60-day harvest plot (76 seeds/spike). The 1,000-seed weight was highest at 50 days after heading but decreased at 60 days. Seed dry matter content increased with delayed harvest, and dry seed yield increased up to 50 days after heading (3,742 kg/ha) but decreased at 60 days (2,442 kg/ha). The dry matter content of seed straw peaked at 50 days after heading, followed by a slight decline at 60 days, which was attributed to rainfall during the harvest period. Dry matter productivity was highest in the 50-day harvest plot. The feed value of seed straw decreased with delayed harvest, with an average Relative Feed Value (RFV) of 83. In conclusion, the optimal harvest time for fall-sown Italian ryegrass for seed production in the mountainous areas of Gangwon is 50 days after heading.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Cultivation of italian ryegrass
    2. Harvesting of italian ryegrass
    3. Evaluation of seed characteristics
    4. Feed value analysis
    5. Weather conditions
    6. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
    1. Growth characteristics
    2. Seed characteristics
    3. Seed and straw yield
    4. Feed value of seed straw
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Xaysana Panyavong(Graduate School of International Agricultural Technology, SNU, Pyeongchang 25354, Republic of Korea)
• Li Zhuang Wu(Graduate School of International Agricultural Technology, SNU, Pyeongchang 25354, Republic of Korea)
• Yan Fen Li(Graduate School of International Agricultural Technology, SNU, Pyeongchang 25354, Republic of Korea)
• Jong Geun Kim(Graduate School of International Agricultural Technology, SNU, Pyeongchang 25354, Republic of Korea, Research Institute of Eco-friendly Livestock Science, GBST, SNU, Pyeongchang 25354, Republic of Korea) Corresponding author
• Ki Jun Choi(Research Institute of Eco-friendly Livestock Science, GBST, SNU, Pyeongchang 25354, Republic of Korea)