This study was conducted at the National Institute of Animal Science from 2010 to 2017. As a variety that is sufficiently productive in the southern regions to replace imported varieties and sufficiently cold-resistant to be cultivated in the central-northern regions, "IR605" was developed and submitted to the Korea Seed & Variety Service in an application for protection. The novel Italian ryegrass variety "IR605" is a diploid with green leaves, a semi-erect growth habit before wintering, and an erect growth habit in the spring. "IR605" was a medium maturing variety with a heading date of around May 15th. "IR605" had a flag leaf width of 9.9 mm, flag leaf length of 26.7 cm, and plant length on the heading date of 100 cm, which was approximately 5 cm longer than "Kowinearly." The stem thickness and ear length of "IR605" are 0.08 mm thicker and 0.5 cm longer than those of "Kowinearly", respectively. The cold-resistance of "IR605" was weaker than that of "Kowinearly", but strong enough to be cultivated in Pyeongchang, Gangwon province. The dry matter yield of "IR605" (9,308 kg/hectare) was 20% higher than that of "Kowinearly", which was further pronounced in the southern region of Haenam, where there was a 52% increased (p < 0.05). The in vitro dry matter digestibility of "IR605" was 68.4% at which was slightly higher than that of "Kowinearly", The total digestible nutrients was 58.5%, which was slightly lower than "Kowinearly". Overall, the feed quality characteristics of "IR605" were similar to those of "Kowinearly".

ABSTRACT
Ⅰ. Introduction
    1. Cross Combination Composition
    2. Combined Line Production
    3. Production Level and Regional Adaptability Evaluation
    4. Feed Value Analysis
Ⅱ. Results and Discussion
    1. Variety Characteristics
    2. Cold-Resistance
    3. Forage productivity
    4. Feed Value
Ⅲ. ACKNOWLEDGEMENTS
Ⅳ. REFERENCES

• Ki-Yong Kim(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration)
• Sang-Hoon Lee(Animal Genetic Resources Research Center, National Institute of Animal Science, RDA)
• Gi Jun Choi(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration)
• Hyung Soo Park(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration)
• Tae-Young Hwang(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration)
• Hee Chung Ji(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration)
• Ki-Won Lee(Grassland and Forage Division, National Institute of Animal Science, Rural Development Administration) Corresponding author