Eok-Keun Ahn*, Ung-Jo Hyun, Kuk-Hyun Jung, Yong-Jae Won, Ha-Cheol Hong, Hyang-Mi Park, Jae-Ki Chang, Jeong-Heui Lee, Jeom-Ho Lee, Nak-Sig Sung, Jung-Pil Suh, Sea-Kwan Oh, and Mi-Ra Yoon. Korean J. Breed. Sci. 2021;53:515-25. https://doi.org/10.9787/KJBS.2021.53.4.515

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).

‘Alchanmi’, a japonica rice variety, was developed from a cross between ‘Junam’ and ‘Chilbo’ by a rice breeding team at the National Institute of Crop Science and Icheon, Agricultural Technology Center in 2018. The heading date of ‘Alchanmi’ was August 10 in the middle plain area — two days later than that of ‘Hwaseong’. ‘Alchanmi’ had a culm length of 69 cm, 16 cm shorter than that of ‘Hwaseong’, and 103 spikelets per panicle. The viviparous germination rate of ‘Alchanmi’ was 24.4%. It showed resistance to blast, bacterial blight (K1, K2, K3 race), and stripe virus, but was susceptible to the K3a race of bacterial blight, dwarf and black streak dwarf viruses, and plant hoppers. The milled rice of this variety exhibited a translucent and medium short grain shape. The cooked rice grains of ‘Alchanmi’ had an excellent palatability index (0.7) and showed lower amylose content (18.6%) than that of ‘Hwaseong’. The grain milling characteristics of ‘Alchanmi’ were better than those of ‘Hwaseong’, especially the head rice milling recovery ratio and head rice ratio (96.2%). ‘Alchanmi’ showed 5.83 MT/ha of milled rice productivity at 6 sites under ordinary cultivation (Registration No. 8132).

Eung-Gi Jeong, Yong-Jae Won, Eok-Keun Ahn, Ung-Jo Hyun, Young-Chan Cho, Jung-Pil Suh, Myoung-Kyu Oh, Jeom-Ho Lee, Ha-Cheol Hong, Chung-Kuen Lee, Yong-Hee Jeon, Ji-Ung Jeung, Hi-Che Chung, Bo-Kyeong Kim. Korean J. Breed. Sci. 2019;51:34-40. https://doi.org/10.9787/KJBS.2019.51.1.34

Jeong-Heui Lee, Yong-Jae Won, Kuk-Hyun Jung, Jae-Ki Chang, Eok-Keun Ahn, Ung-Jo Hyun, Nak-Sig Sung, Eung-Gi Jeong, Young-Chan Cho, Kyeong-Ho Kang, Dae-Ha Seo. Korean J. Breed. Sci. 2019;51:41-7. https://doi.org/10.9787/KJBS.2019.51.1.41

Eung-Gi Jeong, Yong-Jae Won, Chang-Ihn Yang, Young-Chan Cho, Myeong-Ki Kim, Jeong-Heui Lee, Jung-Pil Suh, Sang-Bok Lee, O-Young Jung, Eok-Keun Ahn, Sea-Kwan Oh, Jong-Min Jeong, Ha-Cheol Hong, Ung-Jo Hyun, Young-Jun Mo, Un-Ho Yang, Jeom-Sig Lee, Jeom-Ho Lee, and Bo-Kyeong Kim. Korean J. Breed. Sci. 2018;50:171-6. https://doi.org/10.9787/KJBS.2018.50.2.171

Eok-Keun Ahn*, Eung-Gi Jeong, Sang-Bok Lee, Yong-Hwan Choi, Chang-Ihn Yang, Jeom-Ho Lee, Yong-Jae Won, Gyu-Sung Lee, O-Young Jeong, Young-Jun Mo, Jeong-Ju Kim, Young-chan Cho, Jae-Ki Chang, Myeong-Ki Kim, Jung-Pil Suh, Jeong-Heui Lee, Kuk-Hyun Jung, Jong-Min Jeong, Ji-Ung Jeung, Hyang-Mi Park, Ung-Jo Hyun, and Ha-Cheol Hong. Korean J. Breed. Sci. 2017;49:265-72. https://doi.org/10.9787/KJBS.2017.49.3.265

Yong-Jae Won, Young-Seop Shin, Eok-Keun Ahn, Myeong-Ki Kim, Yeon-Gyu Kim, Jeom-Ho Lee, Yong-Hee Jeon, Kuk-Hyun Jung, Chang-Ihn Yang*, Young-Hwan Yoon, Young-Chan Cho, Areum Chun, Sang-Bok Lee, Myung-Gyu Oh, Hi-Che Chung, Ung-Jo Hyun, and Eung-Gi Jeong. Korean J. Breed. Sci. 2013;45:463-7. https://doi.org/10.9787/KJBS.2013.45.4.463