This study reports the development of a new alfalfa (Medicago sativa L.) variety, ‘Alfaone’, at the Forage Production Systems Division, National Institute of Animal Science, Rural Development Administration, Korea, from 2015 to 2023. The variety originated from an artificial cross between Xun Lu (maternal parent) and RadarⅡ Brand (paternal parent), followed by pedigree selection and performance testing. The elite line ‘MsCB01’ was subsequently released as ‘Alfaone’. Regional adaptability trials were conducted for two years (2022–2023) across four representative sites in Korea (Cheonan, Pyeongchang, Jeongeup, and Jinju) to evaluate agronomic traits, forage yield, and quality. Evaluated characteristics included plant height, regrowth ability, winter survival, and lodging resistance. The average dry matter yield of ‘Alfaone’ was 20,811 kg/ha, approximately by about 3% higher than that of the standard cultivar ‘Vernal’ (20,236 kg/ha). Yield superiority was particularly evident in Pyeongchang, suggesting excellent cold tolerance and winter hardiness. Assessment of forage nutritive traits indicated that ‘Alfaone’ was comparable to ‘Vernal’, demonstrating that its yield advantage did not come at the expense of quality. Overall, ‘Alfaone’ is a promising cultivar that combines high productivity with strong adaptability to unfavorable environments, particularly cold-prone regions. Its release is expected to promote the expansion of alfalfa cultivation, enhance forage self-sufficiency, and reduce dependence on imported hay in Korea.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Selection of lines and development of breeding crosses
    2. Characterization of agronomic traits in ‘Alfaone’
    3. Regional adaptability trials
    4. Forage nutritive value analysis
    5. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
    1. Agronomic characteristics of the new alfalfa variety‘Alfaone’
    2. Dry matter yield of the new alfalfa variety ‘Alfaone’
    3. Forage nutritive value of new alfalfa variety 'Alfaone'
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Ki-Won Lee(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea) Corresponding author
• Chang-Woo Min(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea)
• Bo Ram Choi(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea)
• Hyung Soo Park(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea)
• Yowook Song(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea)
• Sang-Hoon Lee(Forages Production Systems Division, National Institute of Animal Science, Cheonan 330-801, Republic of Korea)