Italian ryegrass (Lolium multiflorum Lam., IRG) is a widely cultivated winter forage crop known for its high yield and nutritional value. This study evaluated the processing characteristics and feeding performance of IRG-based pellets in Hanwoo cattle (Bos taurus coreanae) and Korean native black goats (Capra hircus). IRG was harvested at the optimal growth stage and processed into two pellet formulations: IRG ≥80% (with up to 20% soybean meal) and 100% IRG. Feeding trials were conducted under ad libitum feeding conditions. Hanwoo cattle showed higher intake of 100% IRG pellets (7.9 kg/day/head) than IRG ≥80% pellets (7.5 kg/day/head, p<0.05), with similar average daily gain (0.9 ± 0.4 kg/day/head). Conversely, black goats exhibited significantly lower intake of IRG ≥80% pellets (54.6 g/day/head) compared to 100% IRG pellets (266 g/day/head), likely due to reduced palatability associated with soybean meal inclusion. These findings suggest that IRG pellets are suitable for Hanwoo cattle, while further optimization of pellet size and formulation is required to improve acceptance in goats. Future studies should assess long-term impacts on digestion, rumen fermentation, and metabolic responses.

This study quantitatively assessed the impacts of climate change and extreme weather events on the suitability zones and dry matter yield (DMY) of Italian ryegrass (Lolium multiflorum Lam.) in Korea. Baseline climate (2006–2015) and recent climate (2021–2023) conditions were compared using national meteorological and crop yield data. A significant decrease in total annual precipitation (−84.3 mm, p<0.001) was observed, while winter minimum temperatures showed a slight but statistically insignificant increase (+0.27°C, p = 0.111). Suitability zone classification based on agro-climatic zoning indicated regional shifts, particularly a decrease in the best suitable zones in 2021 and partial recovery by 2023. Dry matter yield increased by 31.6% in central Korea due to improved winter survival under warmer conditions, while southern Korea experienced a 9.4% yield reduction in response to a severe spring drought in 2022. Pearson correlation analysis showed a moderate positive but non-significant relationship between precipitation and yield (r = 0.518, p = 0.292), and multiple linear regression explained 97.9% of yield variation (R² = 0.979). Precipitation had a stronger explanatory effect than temperature, suggesting that water availability is a more critical factor for forage productivity. These findings provide scientific evidence of regional climate sensitivity and support future data-driven cultivation planning.

This study was conducted from 2022 to 2024 at the Grassland and Forage Crops Division, National Institute of Animal Science (RDA), in Cheonan, Korea, to develop a medium-maturing variety of Italian ryegrass (Lolium multiflorum Lam.). The newly developed tetraploid cultivar, named ‘Spider’, is characterized by its green leaves, semi-erect growth habit in late autumn, and erect growth habit in mid-spring. With a heading date of May 16, ‘Spider’ is classified as a medium-maturing variety. Compared to the control cultivar ‘Kowinmaster’, ‘Spider’ has a 1.0 mm wider leaf blade, a 1.6 cm longer leaf blade, and is 5 cm taller in plant height. Its dry matter yield (10,169 kg/ha) is significantly higher than that of ‘Kowinmaster’ (p<0.05). The crude protein content of ‘Spider’ is 10.4%, which is 0.2% higher than that of the control. Additionally, ‘Spider’ has a neutral detergent fiber (NDF) content of 49.5% and an acid detergent fiber (ADF) content of 26.6%, showing a 2.2% lower NDF and a 0.2% higher ADF compared to ‘Kowinearly’.

Italian ryegrass (Lolium multiflorum L.) is an annual forage crop widely cultivated across the globe for its excellent nutritional value and high productivity. Despite its importance, studies on differentially expressed genes (DEGs) involved in its morphogenesis remain limited. In this study, we employed a high-yielding mutant line developed through radiation mutagenesis to identify candidate genes associated with morphogenesis, focusing on Expansins (EXPs), GRFs (Growth regulating factors), GIFs (GRF-interacting factors), and growth hormone-related genes. RT-qPCR primers were designed, and differential gene expression analysis was performed. Gene expression was assessed in the leaves of seedlings at one to three weeks of age, comparing the control cultivar 'Kowinearly' with the mutant line. Expression patterns fell into four distinct categories: (1) genes consistently exhibiting lower expression in the mutant line across all developmental stages; (2) genes showing persistently low expression in the mutant, while the control displayed a sharp increase at early stages followed by a decline; (3) genes with low expression in the control but a marked early-stage increase in the mutant; and (4) genes with decreasing expression over time in the mutant, contrasting with gradually increasing expression in the control. These expression profiles highlight Actin and GRF6 as Group 1 genes, AXR1 (Auxin-resistant protein 1) and EXPB6 (c) as Group 2 genes, PEVMPP1 (Pyrophosphate-energized vacuolar membrane proton pump 1) as a Group 3 gene, and EF1A (Elongation factor 1-alpha) as a Group 4 gene, all of which are key candidate genes for the development of high-yielding Italian ryegrass cultivars.

This experiment was carried out to study the effect of elapsed time after air flow cutoff on the germination rate of Italian ryegrass seed with different moisture contents during natural drying on reclaimed land, Jangheung and Kimje of Korea from 2023 to 2024, respectively. Seeds with moisture contents of 15.3, 22.3 and 28.0% were placed in vinyl bag (30 × 40 cm) at storage thicknesses of 10, 15, and 20 cm, and air flow was cutoff for 48 h. Seed moisture content, seed temperature (℃) and germination rate were investigated at 12-h intervals. After 48 h of airflow cutoff during natural drying, seed moisture content did not significantly differ among storage thickness treatment (p>0.05). When Italian ryegrass seeds with moisture contents of 27~28% were stored under conditions with air flow cutoff at 15~20cm thickness for 48 h, the seed temperature reached up to 30℃ and the germination rate was excellent at around 70~80%.

This experiment was carried out to evaluate the effect of natural drying methods on the moisture content and germination of Italian ryegrass seed in Jicheon reclaimed land, Jangheung, Korea, from 2023 to 2024. The natural drying methods tested included seed spread thicknesses of 2.5, 5.0 and 7.5 cm; seed reversal frequencies of 1, 2 and 3 times per day; and two reversal methods: seed-only reversal and complete mixing of seed with a dry mat. The thinner seed spread thickness significantly accelerated moisture content reduction(p<0.001). However, the reduction in moisture contents due to the number and method of seed reversal was minimal, approximately 1%. Seeds initially having around 48.9% moisture content required 2, 4 and 5 days to reach a moisture content of 14% when dried at spread thickness of 2.5, 5.0 and 7.5 cm, respectively. Seeds with an initial moisture content of 23-26% required 1 to 2 days to reach 14% moisture content while maintaining approximately 80% germination rate under the tested natural drying methods. When seeds with an initial moisture content of 48.9% were dried at a spread thickness of 2.5 cm, the germination rate was 74.6%, which was significantly lower than the 83.8 and 81.6% germination rates observed for seeds dried at 5.0 and 7.5 cm thickness, respectively(p<0.002). These results suggest that for faster drying and higher-quality Italian ryegrass seed, harvesting at 30% seed moisture content, utilizing the cultivation field as a seed drying place, and applying a seed spread thickness of 2.5 to 5.0 cm are optimal practices.

Silage inoculants, which include beneficial microorganisms like lactic acid bacteria (LAB), play a vital role in modern silage production by enhancing fermentation quality. This study evaluated the effectiveness of various commercial inoculants on the fermentation dynamics of Italian ryegrass silage over 45 days. The treatments included a control group and five inoculant formulations: T1 (Lactiplantibacillus plantarum), T2 (Lactiplantibacillus plantarum and Pediococcus pentosaceus), T3 (Lactiplantibacillus plantarum and Pediococcus pentosaceus and Lactiplantibacillus buchneri), T4 (Lactiplantibacillus plantarum and Lactiplantibacillus acidophilus and Lactiplantibacillus bulgaricus), and T5 (Lactiplantibacillus plantarum and Pediococcus pentosaceus and Enterococcus faecium). After 45 days, all treatment groups exhibited significantly higher crude protein (CP) content compared to the control group (80.64 g/kg dry matter (DM), p<0.05). Treatments T2 and T5, which incorporated combinations of Lactiplantibacillus plantarum, Pediococcus pentosaceus and Enterococcus faecium, showed higher CP contents at 105.53 and 107.05 g/kg DM, respectively. The inoculated silages also demonstrated a rapid pH reduction within the early days, with Lactiplantibacillus plantarum in T1 reducing the pH to 4.0 within four days. Additionally, inoculated treatments had significantly higher lactic acid levels than the control (67.96 g/kg DM, p<0.05), and T3 (Lactiplantibacillus buchneri) produced higher acetic acid levels (16.07 g/kg DM, p<0.05) than other inoculants. The control group also had a notably higher ammonia nitrogen content. In conclusion, while single-strain inoculants like Lactiplantibacillus plantarum are effective for rapid acidification, the use of combined bacterial strains can further enhance silage quality by improving lactic acid fermentation and nutrient preservation, particularly in treatments like Lactiplantibacillus plantarum and Pediococcus pentosaceus and Lactiplantibacillus buchneri and Enterococcus faecium.

This study aimed to investigate the metabolic and morphological responses of Italian ryegrass to waterlogging stress during its early growth stage. Waterlogging increased the number of adventitious roots and root porosity, indicating an enhanced oxygen transport mechanism. Phenolic compound levels were increased in both leaf and root tissues under waterlogging stress compared to the control, suggesting the development of a non-enzymatic antioxidant system. Waterlogging treatment also increased reactive oxygen species (ROS) levels only in roots. Total soluble carbohydrates and alcohol dehydrogenase (ADH) activity increased under waterlogging stress, suggesting an increased activity of carbohydrate breakdown and energy conversion mechanisms. This study suggests that Italian ryegrass exhibits significant metabolic and morphological adaptations to waterlogging stress during its early growth stage. These adaptations demonstrate that Italian ryegrass has developed tolerance mechanisms to cope with such stress.

This study was conducted to investigate changes in the productivity of Italian ryegrass seeds according to the timing of harvest after heading in the southern region. The Italian ryegrass variety ‘Greencall’ was sown in Jinju, Gyeongsangnam-do, in the fall of 2022. Four harvest timings were tested (30, 40, 50, and 60 days after heading), with a randomized complete block design and three replicates. Sowing in the test plots took place on October 10, 2022, and harvesting was carried out from 30 days after heading on May 18 to 60 days. The plant height was the longest (99.1 cm) in the plot harvested 30 days after heading and decreased as the harvest was delayed. No significant differences were observed among treatments in terms of lodging resistance, disease resistance, and cold resistance. However, lodging severity increased over time after heading (7∼9). Disease incidence was also higher in plots harvested 50 and 60 days after heading. The length of the spike was shortest (38.76 cm) in the plot harvested 50 days after heading, and the number of seeds per spike was the lowest (42 seeds/spike) in the plot harvested 60 days after heading. The dry matter content of seeds increased with the delay in harvest, while dry matter yield decreased, with the lowest yield observed in the plot harvested 40 days after heading (3,031 kg/ha, p<0.05). The dry matter content of seed straw was highest at 75.73% in the plot harvested 50 days after heading and dropped to 34.99% 60 days after heading due to rainfall. The dry matter productivity of the seed straw was the lowest in the plot harvested 40 days after heading. The feed value of the seed straw also decreased with delayed harvest, with an average RFV (Relative Feed Value) of 91. In conclusion, the optimal harvest timing for fall-sown Italian ryegrass intended for seed production in the southern region appears to be 30 days after heading.

Italian ryegrass (Lolium multiflorum Lam.) is one of the most widely grown winter forage crops in Korea, but its yields are known to be greatly affected by drought that occur frequently in spring. This study aimed to compare the growth and tolerance response characteristics to drought stress in several Italian ryegrass varieties cultivated in Korea. Twenty-day-old Italian ryegrass was subjected to drought treatment for 4 days, and then the growth and physiological responses of the plants were compared. Drought stress reduced leaf length, fresh weight, and dry weight in all Italian ryegrass varieties compared to the control. In addition, chlorophyll content was significantly decreased in all varieties treated with drought stress, but Fv/Fm was significantly decreased only in Winter hawk. For H2O2 and malondialdehyde (MDA) contents, Winter hawk showed the highest increase and New dawn showed the least increase. In terms of relative water content (RWC), New dawn showed the least decrease and Winter hawk showed the greatest decrease. These results indicate that New dawn is relatively drought-tolerant and Winter hawk is a drought-sensitive variety, indicating that each variety of Italian ryegrass has different drought tolerance mechanisms, which may provide basic insight for the development of tolerant varieties in the future.

Italian ryegrass (IRG) has become a vital forage crop due to its increasing cultivation area and its role in enhancing forage self-sufficiency. However, its production is susceptible to environmental factors such as climate change and drought, necessitating precise yield prediction technologies. This study aimed to assess the growth characteristics of IRG and predict dry matter yield (DMY) using vegetation indices derived from unmanned aerial vehicle (UAV)-based remote sensing. The Green Leaf Index (GLI), normalized difference vegetation index (NDVI), normalized difference red edge (NDRE), and optimized soil-adjusted vegetation index (OSAVI) were employed to develop DMY estimation models. Among the indices, GLI demonstrated the highest correlation with DMY (R² = 0.971). The results revealed that GLI-based UAV observations can serve as reliable tools for estimating forage yield under varying environmental conditions. Additionally, post-winter vegetation coverage in the study area was assessed using GLI, and 54% coverage was observed in March 2023. This study assesses that UAV-based remote sensing can provide high-precision predictions of crop yield, thus contributing to the stabilization of forage production under climate variability.

Due to climate change and the expansion of cultivation areas through the use of reclaimed land, changes in the selection of Italian ryegrass (Lolium multiflorum L.) varieties are anticipated. This study was conducted to compare the growth characteristics before overwintering, productivity, and feed value of eight Italian ryegrass varieties with different maturing stages under the same cultivation conditions. The variety ‘Lm4ho’, a medium-maturing type, showed superior growth characteristics before overwintering, including plant height, leaf length, and leaf width. The heading date was advanced in all varieties, with a greater degree of advancement observed in varieties with earlier heading dates. When harvested at the heading stage of the early-maturing types, the dry matter yield of the medium-maturing types was not significantly different from that of the early-maturing types. However, when harvested at the heading stage of the medium-maturing types, the dry matter yield was higher than that of the early-maturing types. Specifically, ‘Lm4ho’ produced 2,518 kg/ha more than ‘Kowinearly’. The late-maturing variety IR901 and the medium-maturing varieties ‘Lm4ho’ and ‘Kowinmaster’ showed statistically superior dry matter yields. In terms of forage value, including crude protein (CP), total digestible nutrients (TDN), and relative feed value (RFV), the medium- and late-maturing types outperformed the early-maturing types. Notably, ‘Lm4ho’, ‘IR 901’, and ‘Hwasan 104’ were evaluated as suitable varieties for high-quality forage production. These results suggest that medium-maturing varieties may be suitable for double cropping in the central regions due to climate change. We propose that future breeding of Italian ryegrass should expand from focusing on cold tolerance and early-maturing varieties to include mediumand late-maturing varieties that consider both productivity and quality.

This experiment was conducted to breed a very early-maturing variety of Italian ryegrass (Lolium multiflorum Lam.) at the Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan, Korea, from 2022 to 2023. The new variety, named “Earlybird,” is a diploid variety characterized by green leaf color, a semi-erect growth habit in late autumn/fall, and an erect growth habit in early spring. With a heading date of April 30, Earlybird is categorized as a very early-maturing variety. Compared to the “Kowinearly” control variety, Earlybird’s flag-leaf width is wider by 0.2 mm, its flag-leaf length is longer by 1.4 cm, and its plant height is greater by 10.5 cm. Additionally, Earlybird’s ear length is 1.4 cm longer than Kowinearly's, and it exhibits lodging resistance. Although the dry matter yield of Earlybird (7,469 kg/ha) is smaller than that of Kowinearly, the difference is not statistically significant. The total digestible nutrient and crude protein content of Earlybird are 63.5% and 8.6%, respectively, which are higher than those of Kowinearly by 1.8% and 0.3%, respectively. The neutral detergent fiber and acid detergent fiber content of Earlybird are 56.9% and 32.0%, respectively, which are lower than those of Kowinearly by 2.2% and 2.3%, respectively.

This study was conducted in Cheonan, the middle region of South Korea, to evaluate the forage characteristics of six medium maturing Italian ryegrass varieties: ‘Kowinmaster’, ‘IR 601’, ‘IR 602’, ‘IR 603’, ‘IR 604’ and ‘IR 605’. In growth characteristics, 'Kowinmaster' exhibited the earliest heading date on April 30, while 'IR 601' exhibited the latest on May 17. 'IR 601' exhibited the highest lodging resistance, and all varieties demonstrated excellent disease resistance, waterlogging tolerance, and cold tolerance. 'IR 603', 'IR 604', and 'IR 605' demonstrated above-average plant length, with 'IR 604' reaching the longest at 114.8 cm. In productivity, 'IR 602' and 'IR 605' produced the highest total dry matter yield, each exceeding 12,800 kg/ha. Regarding feed values, 'Kowinmaster' recorded the highest RFV and TDN at 119.18 and 66.07%, respectively, with 'IR 605' exhibiting the second highest. 'IR 604' and 'IR 601' demonstrated crude protein concentrations over 9%, with 'IR 604' exhibiting the highest at 9.74%. Analysis of monosaccharide content in Italian ryegrass revealed that 'IR 605' exhibited the highest glucose and fructose content at 23.35 g/kg and 50.70 g/kg, respectively. In summary, 'IR 602' exhibited the highest productivity, 'Kowinmaster' recorded the highest feed value, and 'IR 605' exhibited the highest glucose and fructose content. Therefore, 'IR 605' is considered the most outstanding variety due to its superior productivity, second highest feed value, and significant monosaccharide content.

The objective of this study was to compare the feeding effects of imported timothy hay, domestic Italian ryegrass silage (IRGS) and IRG dried by hot-air dry system (IRGHDS) under basic total mixed ration (bTMR) on rumination activity, milk production, and milk composition in lactating dairy cows. Eighteen Holstein dairy cows were divided into three groups: control (bTMR + imported timothy hay), treatment 1 (bTMR + IRGS) and treatment 2 (TMR + IRGHDS) groups. The study was conducted over a total period of 24 days, including a 10 days adaptation period and a 14 days main experimental period. The results indicate body weight was not significantly different between the three groups (p>0.05), and rumination time was significantly higher in the treatment 1 group compared with the control group (p<0.001). Milk fat, protein, and lactose were not significantly different between the three groups (p>0.05), however, somatic cell counts were significantly lower in the treatment 1 group compared with the control group (p<0.001). As a result of the economic feasibility analysis, it is expected that feeding TMR using IRGS and IRGHDS will increase profit by 402.8 won/day and 331.4 won/day per cow compared to imported timothy hay. Therefore, IRGS and IRGHDS can be used as substitutes for imported timothy hay in feeding lactating dairy cows.

The experiment was conducted to determine the changes in seed productivity of Italian ryegrass (Lolium multiflorum Lam.) according to nitrogen fertilization levels in the southern region of Korea. Italian ryegrass (IRG) variety 'Green Call' was sown in the fall of 2021 in Jinju, Gyeongsangnam-do. The experiment consisted of three nitrogen fertilizer levels (100, 120, and 140 N kg/ha) with three replications using a randomized complete block design. Harvesting was done approximately 30 days after heading on May 18th. There was no difference in heading date among treatments, which occurred on April 18th. The longest IRG was observed in the 140 N kg/ha treatment, but there was no significant difference. No significant differences were observed in lodging, disease resistance, and cold tolerance among treatments, but lodging was severe in all treatments. The length of the spike averaged 44.95 cm, with no difference among treatments, and the number of seeds per spike was highest in the 120 N kg/ha treatment. Seed yield increased with increasing nitrogen fertilizer levels, averaging 3,707 kg/ha (as-fed basis). DM content of seed and straw averaged 76.95% and 62.19%, respectively, with no significant differences among treatments. The remaining straw after harvesting averaged 6,525 kg/ha on a dry matter basis, with the highest value observed in the 140 N kg/ha treatment. Overall, considering the results, the optimal nitrogen fertilizer application rate for seed production of Italian ryegrass in the southern region when sown in autumn was found to be 120 N kg/ha.