This study was conducted at the National Institute of Animal Science (NIAS) from 2010 to 2017 to develop a late-maturing variety with high productivity for cultivation in the southern region of South Korea. The new variety of Italian ryegrass, ‘IR901’, was a late-maturing variety, and its heading date was 22 May, 17 days later than that of the control variety ‘Kowinearly’. ‘IR901’ had a flag leaf width of 11.2 mm, flag leaf length of 31.8 cm, and plant length of 103 cm on its heading date. The combined average dry matter yield of ‘IR901’ in all three adaptability evaluation regions (Cheonan, Pyeongchang and Haenam) was 7,747 kg/ha, which was similar to that of the ‘Kowinearly’ variety (7,734 kg/ ha). However, the average dry matter yield over three years in Cheonan and Pyeongchang was 82% and 96%, respectively, compared to that of the control, which was most likely because of the poor cold tolerance of ‘IR901’. By contrast, in Haenam, in the southern region, the average dry matter yield of ‘IR901’ was 19% higher than that of the ‘Kowinearly’ variety. The proportions of crude protein (CP), total digestible nutrients (TDN), acid detergent fiber (ADF), and neutral detergent fiber (NDF) in ‘IR901’ were 8.6%, 59.7%, 36.9%, and 54.8%, respectively; the proportions were 0.2% lower, the same, the same, and 2.5% lower than those in the ‘Kowinearly’ variety. The determined in vitro dry matter digestibility (IVDMD) of ‘IR901’ was 72.2% higher than that of ‘Kowinearly’ (67.2). In general, of the two varieties, the forage quality of ‘IR901’ was marginally superior to that of ‘Kowinearly’.

This experiment was conducted to compare the seed productivity of Spring sown Italian ryegrass(Lolium multiflorum Lam.) depending on the seeding rates(20kg/ha, 30kg/ha, 40kg/ha) in Gangwon region. The experiment was a randomized block design with three replications. The test plots were located in alpine areas of about 600 m above sea level in Gangwon province. The tested Italian ryegrass variety was ‘Greencall’ developed by the National Institute of Animal Science, RDA. Italian Ryegrass was sown on March 26, 2020, and the seed harvesting was on the 60th day(2 July) from heading date. The heading date was May 8 with no difference, There were no significant differences in the agronomic characteristics including plant height. 30kg/ha seed rate was the highest at 146.8 seed/spike and 40kg/ha seed rate was the lowest at 114.7 seed/spike for the number of seeds per spike. The number of spikes per unit area was the highest in 40kg/ha at 886/m2 and the lowest in 20kg/ha at 750/m2. The yield of seed and straw was the highest in 40kg/ha at 1,288kg/ha and 2,970kg/ha respectively, but there was no difference. From the above results, the production of Italian ryegrass seeds through spring sowing in the Gangwon region is not much than autumn seeding, requiring the input of various technologies to increase productivity in the future, and it is desirable to determine the production cost through economic analysis was evaluated.

This experiment was conducted to study on the growth characteristics and seed productivity of Italian ryegrass (Lolium multiflorum Lam., IRG) planted in the Spring in Gangwon Highland according to the seeding distance (20, 30 and 40 cm). The field was located in highland around 600 m above sea level. The experimental design was randomized block design with three replication and the tested IRG variety was ‘Greencall’ developed by National Institute of Animal Science (NIAS). IRG was sown on March 26, 2020, and harvested on July 2. The plant height was the shortest at 80.5 cm in the 40 cm seeding distance plot (P<0.05), and there was no significant difference between the 20 and 30 cm seeding distance. The number of spike per square meter (m2) was significantly higher in the 20 cm seeding distance plot than that of 40 cm (937 vs. 571). The dry matter (DM) content of seed and straw after harvesting was 49.70 and 33.36 % on average, and there was no significant difference between treatments (P>005). However, there was a significant difference in the fresh and DM yield of seeds and straw (P<0.05). DM yield of seeds was significantly higher in 20 cm distance than that of 40 cm, and the yield of straw was the same trend. On the other hand, there was no significant difference in DM yield between 20 cm and 30 cm and also in the feed value of straw after seed harvesting among seeding distance. The average CP, ADF, NDF, and TDN contents were 6.91, 36.76, 61.75 and 59.86%, respectively, and the RFV value was 91. Considering the above results, the production of Italian ryegrass seeds sown in the spring in the highlands of the Gangwon is lower than that of autumn sowing, but it is judged that it needs to be reviewed in case it is unavoidable. In the future, there should be an economic analysis and the development of technology that can increase production.

This experiment was conducted to compare the seed productivity of the Italian ryegrass(Lolium multiflorum Lam.) varieties sown in the spring in Gangwon region. The experiment was randomized block design with three replications. The Experimental field was located in alpine areas of about 600 m above sea level in Gangwon province. The tested Italian Ryegrass varieties were ‘Greenfarm’, ‘Greencall’ and ‘Kowinearly’ developed by National Institute of Animal Science, RDA. Italian Ryegrass varieties were sown on March 26, 2020, and the harvest was on the 60th day of mean heading date, July 2. The heading date of Kowinearly was May 8, but Greenfarm and Greencall was May 4. The plant length was the largest in the Kowinearly variety. However, the Kowinearly suffered severe lodging. There was no significant difference in the length of spike among varieties, and the number of seeds per spike was the lowest in Greenfarm at 118.5 seed/spike. As for the seed weight per spike, the Greenfarm variety was significantly lower at 0.56 g/spike, but the 1,000 seed weight was the heaviest in the Greenfarm at 2.5g.. The number of spike per unit area was the highest in Greenfarm at 906/m2. The dry matter content of seeds was the highest in Greenfarm at 54.3%, and for straw, Kowinearly was the highest at 35.3%. Seed productivity was not significant among varieties, and the average was 1,493 kg/ha. The yield of straw after seed production was also not significant among varieties (P>0.05), and the average was 3,172 kg/ha. From the above results, the production of Italian ryegrass seeds through spring sowing in the Gangwon region is not much than autumn seeding, requiring the input of various technologies to increase productivity in the future, and it is desirable to determine the production cost through economic analysis was judged.

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".

‘Luckyone 2ho’ is a new orchardgrass (Dactylis glomerata L.) cultivar developed by the National Institue of Animal Science (NIAS) in 2017. To develope the new variety of orchardgrass, 5 superior clones were selected and polycrossed for seed production. The agronomic growth characteristics and forage productivity of ‘Luckyone 2ho’ were examined at Cheonan from 2012 to 2014, and regional trials were conducted in Cheonan, Pheonchang, Jinju and Jeju from 2015 to 2017, respectively. ‘Luckyone 2ho’ showed medium type growth habit in fall, and medium in length of flag leaf and very long upper internode. Plant height of ‘Luckyone 2ho’ was 3 cm less than that of standard cultivar, ‘Potomac’ and heading date was 1 days later than 5th May compared to standard cultivar, ‘Potomac’. Characteristics such as waterlogging and disease resistance of ‘Luckyone 2ho’ were stronger or better than those of standard cultivar, ‘Potomac’, Especially, dry matter yield of ‘Luckyone 2ho’(15,980 kg/ha) increased 9 % compared to that of standard cultivar, ‘Potomac’(14,702 kg/ha). Nutritive values were appeared to be similar in both varieties except in Vitro dry matter digestibility(IVDMD) and crude protein and total digestible nutrients (TDN).

This experiment was conducted to breed a very early maturing variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan 2015-2017. The new variety of Italian ryegrass, ‘Green call 2ho’ is a diploid variety with green in leaf color and has semi-erect growth habit in late autumn and erect growth habit in early spring, ‘Green call 2ho’ was in heading date as a early-maturing variety April 24. Also ‘Green call 2ho’ was narrower by 2 mm in flag leaf width, longer by 2.5 cm in flag leaf length and shorter by 3 cm in plant height than those of the control variety, ‘Florida 80’, respectively. ‘Green call 2ho’ was also thicker by 0.33 mm in stem thickness and strong in winter hardness. Dry matter (DM) yield (11,688 kg/ha) of ‘Green call 2ho’ was 7% higher than that of ‘Florida 80’. Total digestible nutrient (TDN), crude protein (CP) and relative feed value (RFV) of ‘Green call 2ho’ were 61.3 %, 9.8 % and 98.2, respectively which are 2.6, 0.6, and 8.4 % higher, respectively than those of ‘Florida 80’, respectively. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) of ‘Green call 2ho’ were 34.9 and 58.5 % which are 3.3 and 2.7 % lower than those of ‘Florida 80’, respectively.

본 시험은 추위에 강하고 생산성이 우수한 이탈리안 라이그라스 품종을 육성하기 위하여 2009년부터 2017년까지 국립축산과학원 초지사료과에서 수행되었다. 이탈리안 라이그라스 신품종 그린콜은 2배체 작물로 엽색은 녹색이며, 월동전 초형은 반직립형, 봄의 초형은 직립형이다. 그린콜은 4월 25일경에 출수하는 극조생종 품종이고 지엽폭이 8 mm, 지엽길이는 24.9 cm 이며, 출수기의 초장은 96 cm로 플로리다 80호 보다 5 cm 정도 짧다. 줄기 두께는 플로리다80호 보다 0.14 mm 굵고 이삭 길이는 플로리다 80호와 대등하다. 그린콜의 건물수량은 11,592 kg/ha로서 대조품종인 플로리다 80호에 비하여 약간 높았다. 상대적 사료가치는 그린콜이 96.7인데 비해 수입종인 플로리다 80호는 89.8로 다소 높고 가소화양분총량 (TDN)이 60.8 %로서 플로리다 80호에 비해 2.1% 높았고, 산성세제불용섬유 (ADF)와 중성세제불용섬유 (NDF)는 각각 35.5 및 58.9 %로서 대조 품종 보다 약간 낮았다.

Cold, salt and heat are the most critical factors that restrict full genetic potential, growth and development of crops globally. However, clarification of genes expression and regulation is a fundamental approach to understanding the adaptive response of plants under unfavorable environments. In this study, we applied an annealing control primer (ACP) based on the GeneFishing approach to identify differentially expressed genes (DEGs) in Italian ryegrass (cv. Kowinearly) leaves under cold, salt and heat stresses. Two-week-old seedlings were exposed to cold (4°C), salt (NaCl 200 mM) and heat (42°C) treatments for six hours. A total 8 differentially expressed genes were isolated from ryegrass leaves. These genes were sequenced then identified and validated using the National Center for Biotechnology Information (NCBI) database. We identified several promising genes encoding light harvesting chlorophyll a/b binding protein, alpha-glactosidase b, chromosome 3B, elongation factor 1-alpha, FLbaf106f03, Lolium multiflorum plastid, complete genome, translation initiation factor SUI1, and glyceraldehyde-3-phosphate dehydrogenase. These genes were potentially involved in photosynthesis, plant development, protein synthesis and abiotic stress tolerance in plants. However, this study provides new insight regarding molecular information about several genes in response to multiple abiotic stresses. Additionally, these genes may be useful for enhancement of abiotic stress tolerance in fodder crops as well a crop improvement under unfavorable environmental conditions.

Glutathione S-transferase (GST) is a key gene involved in multiple stress tolerance in all living organisms, though it is still to be disclosed the gene function in teff grass [Eragrostis tef (Zucc.)Trotter].The objectives of this study were to clone and molecular characterization of GST gene in teff grass. We characterized GST1 from teff grass (EtGST1), it composed of a 645-bp open reading frame (ORF) that encoded 195 amino acid residue. Further, we transformed EtGST1 in E.coli BL21 (DE3) cells. This recombinant EtGST1 in E.coli BL21(DE3) induced at 37°C temperature. In addition, Growth of cells overexpressing EtGST1 rapidly increased in the presence of polyethylene glycol (5%), heat (46°C), NaCl (0.6%), and arsenic (1 mM) than that of cells harboring an empty vector. These results suggest that EtGST1 would be suitable candidate for improving tolerance in forages and/or grasses species against multiple abiotic stresses.

Cold, salt and heat are most critical factors that restrict full genetic potential, growth and development of crops worldwide.. In this study, we applied an annealing control primer (ACP) based GeneFishing approach to identify differentially expressed genes (DEGs) in annual ryegrass (cv. Kowinearly) leaves under cold, salt and heat stresses. Two-week-old seedlings were exposed to cold (4°C), salt (NaCl 200 mM) and heat (42 °C) treatments for 6 h. A total 8 differentially expressed genes were isolated form ryegrass leaves. These genes were sequenced then identified and validated form National Center for Biotechnology Information (NCBI) database. We identified several promising genes encoding light harvesting chlorophyll a/b binding protein, alpha-glactosidase b, chromosome 3B, elongation factor 1-alpha, FLbaf106f03, complete genome, translation initiation factor SUI1, and glyceraldehyde-3-phosphate dehydrogenase. These genes were potentially involved in photosynthesis, plant development, protein synthesis and abiotic stress tolerance in plants. These genes might be useful for the enhancement of abiotic stress tolerance in fodder crops along with crop improvement under unfavorable environmental conditions.

breakdown of tooth-supporting tissues, producing dentition loss. Porphyromonas gingivalis (P. gingivalis), a Gramnegative anaerobic rod, is one of the major pathogens associated with periodontitis. Neutrophils are first line defense cells in the oral cavity that play a significant role in inflammatory response. Xylitol is a known anti-caries agent and has anti-inflammatory effects. In this study, we conducted experiments to evaluate anti-inflammatory effects of xylitol on P. gingivalis infected neutrophils for possible usage in prevention and treatment of periodontal infections. P. gingivalis was intraperitoneally injected and peritoneal lavage was collected for cytokine determination. For in vitro study, neutrophils were collected from mouse peritoneal cells after zymosan injection or bone marrow cells. Neutrophils were stimulated with live P. gingivalis and ELISA was used to determine the effect of xylitol on P. gingivalis induced cytokine production. IL-1β, IL-6, TNF-α concentration and neutrophil population in the peritoneal lavage was increased in P. gingivalis-infected mouse. Peritoneal cells infected with live P. gingivalis revealed significantly increased production of IL-1β, IL-6 and TNF-α at multiplicity of infection of 10. Neutrophils from bone marrow and peritoneal lavage revealed increased production of IL-1β, IL-6 and TNF-α. Xylitol significantly mitigated P. gingivalis induced cytokine production in neutrophils. Findings indicate that xylitol is an anti-inflammatory agent in neutrophils infected with live P. gingivalis, that suggests its use in periodontitis management.

The objective of this study was to investigate the suitable method for rapid establishment of grassland according to forage species, mixed pastures and installation of mesh at 35 degree angle of cutting area in the middle region of Korea. In agronomic characteristics after wintering, vegetation coverage of Tall fescue(TF) was 74% in monoculture, which was the highest among 3 forage crops. Meanwhile average vegetation coverages of monoculture and mixed pasture were 67 and 92% in treated of mesh, which were 4 and 18% higher than untreated of mesh, respectively. In botanical composition, TF of monoculture and Orchardgrass(OG) and TF oriented mixed were indicated over 94% forage coverage. Meanwhile forage coverages Kentucky bluegrass(KBG) and Red top(RT) of monoculture and Perennial ryegrass(PRG) oriented mixture were 89, 81 and 92% in treated of mesh, which were 7, 6 and 5% higher than untreated of mesh, respectively. In forage productivity, dry matter yield(DMY) of TF(12,537kg/ha) and KBG(11,897kg/ha) of monoculture were significant(p<0.05) higher than RT(9,604kg/ha). Meanwhile DMY of OG(12,227kg/ha), TF(12,823kg/ha) and PRG(11,871kg/ha) oriented mixed were not significant difference(p>0.05). In forage quality of monoculture, in the first year, crude protein of KBG was 13.6%, which was the highest among 3 forage species. Also neutral detergent fiber(NDF) of TF was 56.5%, which was the lowest among 3 forage species. In mixed pasture, in the second year, NDF and acid detergent fiber of PRG oriented mixed were 56.5 and 34.3%, respectively, which was the lowest among 3 mixed pasture. In conclusion, forage species TF was more suitable on initial rootage and continuous forage coverage, OG and TF oriented mixed were more suitable on continuous forage coverage. Also the installation of mesh showed positive effects on initial rootage and maintain forage ratio.

This study was carried out to introduce of agronomic characteristics, forage yields and quality of Sorghum × Sudangrass hybrids ‘Cadan 99B’ and ‘Sweet Sioux WMR’ from 2015 to 2016 in middle and southern regions of Korea. The field experiment design was complete in seven varieties with three repetitions. Sorghum × Sudangrass hybrids were sown on mid-May in middle region, and end-May in southern region of Korea, in 2015 and 2016. The observed average heading date of Cadan 99B and Sweet Sioux WMR were July 22. The heading dates of Cadan 99B and Sweet Sioux WMR were 8 days earlier than SX-17 and 5 days earlier than brown mid-rid (BMR) Revolution. The sugar contents of Cadan 99B and Sweet Sioux WMR were 6.5 and 6.9 Brix°, respectively. Comparison with BMR variety, the sugar contents of Candan 99B and Sweet Sioux WMR were 0.2 and 0.6 Brix° higher than Revolution, respectively. The average of dry matter (DM) yield for 2 years and 2 regions of Cadan 99B (24,587kg/ha) were the highest among the seven varieties, but there was no significant difference among other varieties except headless control variety Jumbo (19,119kg/ha) and LATTE (20,778kg/ha) (p>0.05). The crude protein (CP) and in vitro dry matter digestibility (IVDMD) of Cadan 99B were 7.5% and 60.2%, and Sweet Sioux WMR were 6.9% and 60.7%, respectively. The results of this study indicated that Sorghum × Sudangrass hybrids Cadan 99B and Sweet Sioux WMR are earlier heading dates and higher than SX-17, and high yields of DM in middle and southern regions of Korea.

This experiment was carried out to compare the growth characteristics and productivity between sudangrass and sorghum-sudangrass hybrid under the same cultivation condition in Cheonan and Kimje of Korea from 2010 to 2011. Sudangrass hybrids(Choice, Sunstar and Piper) and sorghum-sudangrass hybrids(SX-17, Jumbo and Revolution) were planted 5th May in Cheonan and 7th May in Kimje. Heading date of sudangrass hybrids was 12th July which was about 2 week fast more than that of sorghum-sudangrass hybrids. Stem diameter of sudangrass hybrids was about 6mm which was about 5 mm smaller than that of sorghum-sudangrass hybrids. Disease resistance of sudangrass hybrid, “Choice” was similar to that of sorghum-sudangrass hybrids. Dry matter yield of “Choice” was 15ton/ha which was 10% less than that for sorghum-sudangrass hybrids(SX-17). Feed value of “Choice” was similar or slightly lower than that of sorghum-sudangrass. For increasing the productivity in forage cropping systems all around year, sudangrass hybrid is recommended for prolong by the middle ten day of May in the harvesting time of italian ryegrass

This experiment was carried out to study the effect of rice black-streaked dwarf virus(RBSDV) infection rate on forage productivity of corn varieties in Cheonan of chungcheongnamdo from 2006 to 2008. Forage corn varieties of 10 were cultivated with first cropping(seeding in the last ten days of April) and second cropping(seeding in the last ten days of May) system in field and tested the infection rates of RBSDV and productivity of forage. The Infection rate of RBSDV was significant difference between corn varieties in middle district of Korea. Resistant corn varieties for RBSDV were ‘Kwanganok’, ‘P3156’, ‘Kwangpeyongok’ and ‘P3394’ but susceptible varieties were ‘Suwon19’, ‘DK697’, ‘GW6959’ and NC+7117. Dry matter(DM) yield of forage corn according with infection rates of RBSDV in field was significant difference between varieties(p<0.05). DM yield of susceptible varieties, ‘Suwon 19’, ‘DK697’ and ‘GW6959’ was lower about 20% than that of resistant varieties, ‘Kwangpeyongok’ and ‘P3156’. For increasing the productivity of forage corn, recommend of resistant varieties for RBSDV and control of seeding time are very important in middle district of Korea.

Background: Periodontitis is an inflammatory disease characterized by the breakdown of tooth-supporting tissues, leading to tooth loss. Aggregatibacter actinomycetemcomitans are major etiologic bacterium causing aggressive periodontitis. Ursodeoxycholic acid (UDCA), a hydrophilic gall bladder acid, has been used as an effective drug for various diseases related to immunity. The aim of this study was to investigate the effect of UDCA on the inflammatory response induced by A. actinomycetemcomitans. Methods: A human acute monocytic leukemia cell line (THP-1) was differentiated to macrophage- like cells by treatment with phorbol 12-mystristate 13-acetate (PMA) and used for all experiments. The cytotoxic effect of UDCA was examined by MTT assay. THP-1 cells were pretreated with UDCA for 30 min before A. actinomycetemcomitans infection and the culture supernatant was analyzed for various cytokine production by ELISA. The effect of UDCA on bacterial growth was examined by measuring optical densities using a spectrophotometer. Results: UDCA showed no cytotoxic effect on THP-1 cells, up to 80 μM Ed highlight: Please confirm technical meaning. UDCA pretreatment inhibited the A. actinomycetemcomitansinduced IL-1β, TNF-⍺, and IL-17A secretion in a dosedependent manner. UDCA also inhibited IL-21 production at 60 μM. The production of IL-12 and IL-4 was not influenced by A. actinomycetemcomitans infection. Conclusion: These findings indicate that UDCA inhibits the production of inflammatory cytokines involved in innate and Th17 immune responses in A. actinomycetemcomitansinfected THP-1- derived macrophages, which suggests its possible use for the control of aggressive periodontitis.

Background: Periodontitis is generally a chronic disorder characterized by the breakdown of tooth-supporting tissues. P. gingivalis, a Gram-negative anaerobic rod, is one of the major pathogens associated with periodontitis. Frequently, P. gingivalis infection leads to cell death. However, the correlation between P. gingivalis–induced cell death and periodontal inflammation remains to be elucidated. Among cell deaths, the death of immune cells appears to play a significant role in inflammatory response. Thus, the aim of this study was to examine P. gingivalis–induced cell death, focusing on autophagy and apoptosis in THP-1 cells. Methods: Human acute monocytic leukemia cell line (THP-1) was used for all experiments. Autophagy induced by P. gingivalis in THP-1 cells was examined by Cyto ID staining. Intracellular autophagic vacuoles were observed by fluorescence microscopy using staining Acridine orange (AO); and 3-methyladenine (3-MA) was used to inhibit autophagy. Total cell death was measured by LDH assay. Cytokine production was measured by an ELISA method. Results: P. gingivalis induced autophagy in an MOI-dependent manner in THP-1 cells, but 3-MA treatment decreased autophagy and increased the apoptotic blebs. P. gingivalis infection did not increase apoptosis compared to the control cells, whereas inhibition of autophagy by 3-MA significantly increased apoptosis in P. gingivalis-infected THP-1 cells. Inhibition of autophagy by 3-MA also increased total cell deaths and inflammatory cytokine production, including IL-1β and TNF-⍺. Conclusion: P. gingivalis induced autophagy in THP-1 cells, but the inhibition of autophagy by 3-MA stimulated apoptosis, leading to increased cell deaths and pro-inflammatory cytokines production. Hence, the modulation of cell deaths may provide a mechanism to fight against invading microorganisms in host cells and could be a promising way to control inflammation.

This experiment was carried out to investigate the effect of harvesting time of Italian ryegrass (Lolium multiflorum Lam; IRG) in spring on dry matter (DM) yield. IRG cultivars ‘Kowinearly’ and ‘Greenfarm’ were seeded at 50 kg/ha and grown on rice paddy fields. There was no difference in growth characteristics between both varieties before winter. However, cold tolerance of Kowinearly was higher than that of Greenfarm, as demonstrated by post-wintering growth characteristics. The heading date of both varieties was affected by the spring weather. The IRG was harvested three times at 5-day intervals beginning from 9 May. The DM yield of Greenfarm was 6,306; 7,335; and 8,109 kg/ha, and that of Kowinearly was 7,498; 9,196; and 10,449 kg/ha at the three consecutive harvests. The delay of the harvesting time for 5 and 10 days increased the DM yield of Greenfarm by 16% and 29% and that of Kowinearly by 23% and 39%, respectively, compared to the yield at first harvest (p < 0.05). Therefore, IRG harvest later than early to mid-May is expected to increase productivity. The feed values of Greenfarm were: 12.2% of crude protein (CP), 34.5% of acid detergent fiber (ADF), 57.7% of neutral detergent fiber (NDF), 61.6% of total digestible nutrients (TDN), and 72.3% of in vitro DM digestibility (IVDMD). For Kowinearly, these values were 16.4% of CP, 30.4% of ADF, 52.7% of NDF, 64.9% of TDN and 79.0% of IVDMD.