‘Miwoo’ is a mid-late maturing, high-biomass-yielding rice (Oryza sativa L.) cultivar with high feed value and resistance to multiple diseases and insect pests. It was developed for use as whole crop silage (WCS) from a cross between ‘Suweon519’, a line with high biomass yield and multiple disease resistance, and ‘Suweon518’, a medium flowering, high yielding Tong-il type line, which is resistant to blast (BL), bacterial blight (BB) (race K1), rice stripe virus (RSV) and brown planthopper (BPH). In the central plain region of Suwon, ‘Miwoo’ cultivar exhibited a growth period of approximately 122 days from seeding to heading, culm length of 99 cm, panicle length of 28 cm, 12 panicles per hill, 143 spikelets per panicle, and 1,000-grain weight of 25.9 g as brown rice. This mid-late-flowering rice variety was resistant to lodging during the yellowing ripening stage, an optimal period for harvesting. In addition, ‘Miwoo’ was strongly resistant to leaf and neck blast, BB (race K1, K2, K3, K3a), RSV, BPH and small BPH. Its average dry matter yield over 3 years reached 19.9 MT/ha, which is 36% higher than that of ‘Nokyang’. ‘Miwoo’ is a high-amylose cultivar with 70.7% total digestible nutrients (similar to that of Nokyang) and grows well on the central and southern plains of the Korean Peninsula. It should be harvested 30 days after heading to improve its feed value and digestion rate in livestock. (Registration No. 7683)

‘Jonong’ is an early maturing whole crop silage (WCS) japonica rice cultivar characterized by a short growth duration and numerous spikelets. It was developed to enhance the adaptability of WCS rice to double-cropping systems. ‘Jonong’ is derived from a cross between ‘Binhae Col.#1’ and ‘Deuraechan’; ‘Binhae Col.#1’ is a semi-early maturing China rice germplasm with numerous spikelets on dense panicles, whereas ‘Deuraechan’ is a high-yielding japonica rice cultivar with numerous spikelets on long panicles. To diversify the genetic variation and shorten the breeding period, an anther culture method was applied to the F₁ plants. ‘Jonong’ was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for short growth duration and high biomass. The average heading date of ‘Jonong’ was August 1^st, which is 11 days earlier than that of ‘Nokyang’, the standard cultivar for WCS rice. Moreover, the growth duration of ‘Jonong’ is the shortest among all Korean WCS rice cultivars. The culm length of ‘Jonong’ is 88 cm, which 4 cm longer than that of ‘Nokyang’ and the highest among all Korean early maturing rice cultivars. ‘Jonong’ has 149 spikelets per panicle, which is 30 more than that of ‘Nokyang’, and is the highest among all Korean early maturing rice cultivars. ‘Jonong’ exhibits stable premature heading and is tolerant to lodging. It is moderately resistant to leaf blast and resistant to the rice stripe virus. The feed value of ‘Jonong’ in terms of total digestible nutrients is good and comparable to that of ‘Nokyang’. Furthermore, compared with ‘Nokyang’, ‘Jonong’ shows a similar level of dry matter yield and a higher rough rice yield. Therefore, ‘Jonong’, an early maturing WCS japonica rice with short growth duration and numerous spikelets, would be suitable for cultivating in winter forage crop-rice double cropping systems (Registration No. 7274).

‘Jowoo’, an early maturing, high biomass yielding rice (Oryza sativa L.) cultivar with high feed value and multiple disease-insect resistance, was developed for winter forage crop-whole crop silage (WCS) rice double cropping. It was derived from a cross between a high biomass and multiple disease resistant line ‘Suweon519’ and an early flowering, high yielding Tong-il type variety ‘Gaya’ that harbored Bph3 and BPH26, conferring brown planthopper (Bph) broad resistance. This cultivar had a growth period of approximately 106 days from seeding to heading, 97 cm culm length, 24 cm panicle length, 12 panicles per hill, 120 spikelets per panicle, and 1,000-grain weight of 22.1 g as brown rice in the central plain region of Suwon. This early flowering rice variety was tolerant to premature germination and cold stresses, especially showed higher grain fertility than ‘Nokyang’ at a cold-water (17℃) irrigated screening nursery. Further, ‘Jowoo’ exhibited high lodging resistance in the yellowing ripening stage, an optimal period for harvest. In addition, ‘Jowoo’ was resistant to leaf and neck blast, bacterial blight (race K1, K2, K3, K3a), rice stripe virus, and small Bph and was also moderately resistant to Bph. Its average dry matter yield for three years reached 18.2 MT/ha, the highest among early flowering rice varieties and 19% higher than that of ‘Nokyang’. This cultivar had 72.2% total digestible nutrients, which is also higher than that of ‘Nokyang’. In the Korean peninsula, ‘Jowoo’ grows well in the central and southern plains and can be harvested 30 days after heading. This helps improve its feeding value and digestion rate in livestock (Grant No. 8133).

‘Cheongwoo’, a late maturing, high biomass-yielding rice (Oryza sativa L.) cultivar with high feed value and multiple disease and insect resistance, was developed for whole crop silage (WCS) use. It was derived from a cross between a high biomass and multiple disease resistant line ‘Suweon519’ and early flowering, high-yielding Tong-il type cultivar ‘Gaya’, which exhibited a brown planthopper (BPH) broad resistance conferred by Bph3 and BPH26. The cultivar was characterized by growth period from seeding to heading of about 130 days, culm length of 87 cm, panicle length of 29 cm, 12 panicles per hill, 135 spikelets per panicle, and 1,000-grain weight of brown rice of 21.4 g in the central plain region, Suwon. This long-leaved green WCS rice variety was sensitive to cold stress, similar to ‘Nokyang’, but resistant to premature germination, and germinated well under low temperature conditions. Furthermore, ‘Cheongwoo’ exhibited high lodging resistance at the yellowing stage, the optimal period for harvesting in the field. Additionally, ‘Cheongwoo’ was resistant to leaf and neck blast, bacterial blight (races K1, K2, K3, K3a), rice stripe virus, BPH, and small BPH. Its average dry matter yield for three years reached 20.6 MT/ha, 38% higher than that of ‘Nokyang’. The content of crude protein (5.32%) and total digestible nutrients (71.2%) was higher than that in ‘Nokyang’. On the Korean Peninsula, ‘Cheongwoo’ grows well in central and southern plains, and should be optimally harvested between 15 and 30 days after heading to improve its feeding value and digestion rate in livestock (Grant No. 7662).

Salt stress is a significant factor limiting growth and productivity in crops. However, little is known about the response and resistance mechanism to salt stress in maize. The objective of this research was to develop an enhanced salt-tolerant silage maize by mutagenesis with gamma radiation. To generate gamma radiation-induced salt-tolerant silage maize, we irradiated a KS140 inbred line with 100 Gy gamma rays. Salt tolerance was determined by evaluating plant growth, morphological changes, and gene expression under NaCl stress. We screened 10 salt-tolerant maize inbred lines from 2,248 M₂ mutant populations and selected a line showing better growth under salt stress conditions. The selected 140RS516 mutant exhibited improved seed germination and plant growth when compared with the wild-type under salt stress conditions. Enhanced salt tolerance of the 140RS516 mutant was attributed to higher stomatal conductance and proline content. Using whole-genome re-sequencing analysis, a total of 328 single nucleotide polymorphisms and insertions or deletions were identified in the 140RS516 mutant. We found that the expression of the genes involved in salt stress tolerance, ABP9, CIPK21, and CIPK31, was increased by salt stress in the 140RS516 mutant. Our results suggest that the 140RS516 mutant induced by gamma rays could be a good material for developing cultivars with salt tolerance in maize.

‘Yeongwoo’, a mid-late flowering, high dry matter yielding rice (Oryza sativa L.) cultivar with high feed value and multiple disease-insect resistance, was developed for whole crop silage (WCS) use. It was derived from a cross between a high biomass and brown planthopper (Bph) resistant ‘SR25848-C99-1-2-1’ and high yielding Tong-il type, ‘Yongmun’ which had diseases resistance. This cultivar had about 117 days growth period from seeding to heading, 99 cm culm length, 26 cm panicle length, 11 panicles per hill, 125 spikelets per panicle, and 1,000-grain weight of 23.6 g as brown rice in the central plain region, Suwon. This wide and long leafy WCS rice variety was weak to cold stresses, similarly to ‘Nokyang’ but was resistant to lodging in the field, strong to viviparous germination, and good under low temperature germination. In addition, ‘Yeongwoo’ was resistant to leaf and neck blast, bacterial blight (race K1, K2, K3, K3a), rice stripe virus, Bph, and small Bph. Its average dry matter yield for three years reached 20.0 MT/ha, 32% higher than that of ‘Nokyang’. This cultivar had 5.3% crude protein and 71.7% total digestible nutrients, which was slightly lower than that of ‘Nokyang’. In the Korean peninsula, ‘Yeongwoo’ grew well in the central and southern plain and was could be harvested between 15 to 30 days after heading to improve the feeding value and digestion rate of livestock (Grant No. 6800).

‘Nokwoo’, a mid-late maturing, high dry matter yielding rice (Oryza sativa L.) cultivar with a good early growth and low-temperature germinability, was developed for whole crop silage (WCS) use. It was derived from a cross between a leafy tropical japonica ‘LK1A-2-12-1-1’ with high biomass and good germinability in low temperature and new plant type (NPT), ‘IR72225-29-1-1’ which had low tillering trait, large panicle, dark green leaf, thick and sturdy stem and vigorous root system. This cultivar had about 123 days growth period from seeding to heading, 122㎝ culm length, 29㎝ panicle length, 9 panicles per hill, 144 spikelets per panicle and 1,000-grain weight of 24.4 g as brown rice in central plain region, Suwon. This wide and long leafy WCS rice variety was weak to cold stresses similar to ‘Nokyang’ but was a little resistant to lodging in the field, strong to viviparous germination and good to low temperature germination. In addition, ‘Nokwoo’ was resistant to leaf and neck blast but susceptible to bacterial blight, rice stripe virus and brown planthopper. Its average dry matter yield for three years reached 16.5 MT/ha, 14% higher than that of ‘Nokyang’. This cultivar had 5.3% crude protein and 68.8% total digestible nutrients a little low compared to ‘Nokyang’. In Korea peninsular, ‘Nokwoo’ grows well in central and southern plain and is good to harvest between 15 to 30 days after heading to improve its feeding value and digestion rate of livestock (Grant No. 6072).

‘Jungmo1038', a mid-late maturing, high dry matter yielding rice (Oryza sativa L.) cultivar with glabrous leaf and hull, was developed for whole crop silage (WCS) use. It was derived from a cross between ‘SR24592-HB2319’ with high biomass, smooth leaf and hull and good germinability in low temperature and new plant type (NPT), ‘IR73165-B-6-1-1‘ which had low tillering trait, large panicle, dark green leaf, thick and sturdy stem and vigorous root system. This cultivar had about 125 days growth period from seeding to heading, 99cm culm length, 20cm panicle length, 13 panicles per hill, 119 spikelets per panicle and 1,000-grain weight of 23.3 g as brown rice in central plain region, Suwon. This hairless WCS rice variety was weak to cold stresses similar to ‘Nokyang’ but was resistant to lodging in the field, strong to viviparous germination and good to low temperature germination. In addition, ‘Jungmo1038’ was resistant to leaf and neck blast but susceptible to bacterial blight, rice stripe virus and brown planthopper. Its average dry matter yield for three years reached 17.2 MT/ha, 21% higher than that of ‘Nokyang’. This glabrous cultivar had 6.6% crude protein and 62.4% total digestible nutrients a little low compared to ‘Nokyang’. In Korea peninsular, 'Jungmo1038' grows well in central and southern plain and is good to harvest between 15 to 30 days after heading to improve its feeding value and digestion rate of livestock(Grant No. 5634).

‘Jungmo1029’, a late-maturing, high biomass and multiple disease resistant rice (Oryza sativa L.) cultivar, was developed for whole crop silage (WCS) use. It was derived from a cross between ‘Gillim collection1’ with high biomass and ‘Junam’ which has some of diseases resistant genes. This elite cultivar had about 127 days growth period from seeding to heading, 105 cm culm length, 11 panicles per hill, 163 spikelets per panicle and 1,000-grain weight of 21.5 g as brown rice. This WCS rice variety was weak to cold stresses similar to ‘Nokyang’ but was tolerant to lodging in the field. In addition, ‘Jungmo1029’ was resistant to leaf and neck blast, bacterial blight except race K3a and rice stripe virus but susceptible to brown planthopper. Its average dry matter yield for three years reached 17.1 MT/ha, 14% higher than that of ‘Nokyang’. This stay green cultivar had good quality for WCS with low acid detergent fiber and high total digestible nutrients similar to ‘Nokyang’. ‘Jungmo1029’ was suitable for cultivation in the central and southern plain area of the South Korean peninsula and required to harvest 15~30 days after heading to improve the digestibility of cattle (Registration No. 5104).