Italian ryegrass (Lolium multiflorum Lam.) is a major winter forage crop requiring improved drought tolerance under climate change. This study evaluated 42 accessions, consisting of 20 Korean cultivars and 22 exotic germplasm under four polyethylene glycol (PEG) concentrations (0, 10, 15, and 20%) to assess germination and early seedling responses to drought stress. Increasing PEG levels significantly reduced germination percentage (GP), germination energy (GE), germination index (GI), and seedling vigor index (SVI), while mean germination time (MGT) increased. At 20% PEG, GP decreased by approximately 74% compared with the control. Early seedling vigor, expressed as SVI (integrating fresh weight, shoot length, and root length) also declined depending on concentration. Germination traits (GE and GI) showed strong positive correlations with SVI, indicating that early germination performance was closely associated with subsequent growth under drought stress. Fuzzy comprehensive evaluation and principal component analysis consistently identified several accessions (Earlybird, IR602, IR901, Florida 98, Maximus, Orlando, and Moscovsky 74) as relatively drought tolerant. Overall, the integration of germination and seedling vigor index provides a reliable phenotypic screening approach for identifying drought-tolerant Italian ryegrass.

ABSTRACT
Ⅰ. 서론
Ⅱ. 재료 및 방법
    1. 시험품종 및 PEG 처리
    2. 발아 관련 지수 평가
    3. 통계 분석
Ⅲ. 결과 및 고찰
    1. PEG 처리에 따른 발아 지표 변화 및 효과 분석
    2. 발아 및 생육 형질 간 상관관계 분석
    3. 내건성 수준의 종합 평가 및 다변량 분석
Ⅳ. 요약
Ⅴ. 사사
Ⅵ. REFERENCES

• 김정민(국립축산과학원 조사료생산시스템과) | Jung Min Kim (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 민창우(국립축산과학원 조사료생산시스템과) | Chang-Woo Min (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 이기원(국립축산과학원 조사료생산시스템과) | Ki-Won Lee (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 최보람(국립축산과학원 조사료생산시스템과) | Bo Ram Choi (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 박형수(국립축산과학원 조사료생산시스템과) | Hyung Soo Park (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 이상훈(국립축산과학원 조사료생산시스템과) | Sang-Hoon Lee (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• 송요욱(국립축산과학원 조사료생산시스템과) | Yowook Song (Forages Production Systems Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea) Corresponding author