This study was conducted to reset the transplanting period to produce high-quality rice in the South regions due to the rise in air temperature caused by global warming. From May 15 to June 25, transplants were performed five times every ten days. Quantity and quality were comprehensively reviewed, including watering season, ripened grain rate, head rice rate, head rice yield, protein content, and palatability. In the southern plains, medium-late and medium maturing cultivars yielded the most when transplanted on June 15, while early maturing cultivars yielded the most when transplanted on June 25. Considering the quality and quantity of rice, the optimal transplanting window for medium-late maturing cultivars is June 10-15, for medium maturing cultivars it is June 15-20, and for early maturing cultivars it is June 25. In the middle of the southern region, the highest yield was on June 25 for medium-late maturing and June 15 for medium maturing and early maturing. However, considering the quality, the best time for transplanting is June 10 for medium-late maturing, June 5 for medium maturing, and June 15 for early maturing. As a result of the rise in average temperature, the transplantation period was delayed by at least 4 to 16 days in all varieties and regions relative to the traditional transplantation duration. In summary, it is determined that a suitable transplanting period must be established in response to the increase in average temperature to ensure the production of high-quality rice.

‘Yeongbo’ is a variety of japonica rice (Oryza sativa L.) with good eating quality, resistance to rice stripe virus, rice dwarf virus, and bacterial blight disease. It was developed by the rice breeding team of the Yeongdeok Branch, National Institute Crop Science, Rural Development Administration in 2014. This variety was derived from a cross between ‘Yeongdeog35’ with good eating quality and ‘Saekyehwa’ with good plant type in the 2002 summer season. A promising line selected through the pedigree breeding method, YR24269-1-2-1-2-3-3, was designated as ‘Yeongdeog57’ in 2011. After a local adaptability test at nine locations from 2012 to 2014, ‘Yeongdeog57’ was released under the name of ‘Yeongbo’ in 2014. ‘Yeongbo’ had a short culm length of 66 cm and medium growth duration. This variety was resistant to K1, K2, and K3 races of bacterial blight, rice stripe virus, and dwarf virus, and moderately resistant to leaf blast disease. ‘Yeongbo’ had translucent and clear milled rice kernel without white core and belly, and good eating quality according to a panel test. The yield potential of ‘Yeongbo’ in milled rice was approximately 5.75 MT/ha at an ordinary fertilizer level in the local adaptability test. This cultivar would be adaptable to middle plain area, south plain area, Yeongnam plain area, east costal area, and south mid-mountainous area. (Registration No.6804)

‘Haepum’ is a bacterial blight-resistant, medium maturing rice cultivar with high grain quality. It was derived from a cross between ‘Iksan493’ (cultivar name ‘Jinbaek’) and the F₁ cross between ‘Iksan495’ (‘Dacheong’) and ‘Iksan496’ (‘Jungmo1005’). Of these three cultivars, ‘Jinbaek’ is a bacterial blight-resistant mid-late maturing rice cultivar with high grain quality, ‘Dacheong’ is a mid-late maturing rice cultivar with multiple resistance to disease and insects, and ‘Jungmo1005’ is a mid-late maturing rice cultivar with lodging tolerance. To develop fixed lines, the anther culture method was applied to F₁ plants. The cultivar ‘Haepum’ was selected using the pedigree method, yield trials, and local adaptability tests. The heading date of ‘Haepum’ was August 11^th, three days earlier than that of ‘Nampyeong’ cultivar. Haepum’ is a cultivar tolerant to lodging and it has short culms. Due to its low rate of viviparous germination, ‘Haepum’ could be useful for preventing pre-harvest sprouting in cultivation of medium maturing rice in the southern plain area of Korea. ‘Haepum’ carries two bacterial blight resistance genes (Xa3 and xa5), and in our study, it exhibited high-level and broad-spectrum resistance against bacterial blight, including K3a, the most virulent race in Korea. ‘Haepum’ is also resistant to the rice stripe virus and moderately resistant to rice blast. The yield of ‘Haepum’ was similar to that of ‘Nampyeong’. ‘Haepum’ showed excellent grain appearance and good taste of cooked rice, and therefore it could contribute to the development of bacterial blight-resistant rice cultivars of improved quality. ‘Haepum’ would be suitable for cultivation in the southern plain area of Korea as well as in bacterial blight-prone areas. (Registration No. 6068)

‘Jungmo1033’, a japonica rice variety, was developed by the rice breeding team at the National Institute of Crop Science (NICS) in 1992. It is derived from a cross between a native variety ‘Jagwangdo’, which has translucent milled rice and medium maturity; and ‘Hwayeong’, which is an elite line with bacterial blight resistance and mid-late maturity. The heading date of ‘Jungmo1033’ was August 10 in the middle plain area of Korea, which was two days later than that of ‘Hwaseong’. ‘Jungmo1033’ has a culm length of 79 cm, which was 5 cm shorter than that of ‘Hwaseong’, and 105 spikelets per panicle. ‘Jungmo1033’ showed resistance to bacterial blight (K1, K2, and K3 races) and stripe virus, but susceptibility to the K3a race of bacterial blight, dwarf and black-streaked dwarf viruses, and planthoppers. The milled rice of this variety exhibited translucency and a medium short grain shape. It had an excellent appearance and lower amylose content (19.1%) than that of ‘Hwaseong’. The characteristics related to grain milling were better than those of ‘Hwaseong’, especially head rice milling recovery ratio and head rice ratio (94.8%). ‘Jungmo1033’ showed a milled rice productivity of 5.38 MT/ha at 11 sites under ordinary cultivation conditions. (Registration No. 5723)

“Samkwang1,” a japonica rice variety, was developed as a cross between “Samkwang” and F1 of Suwon152 (IT008283), which has a medium maturing and lodging resistance and Samkwang (IT284608), a high quality variety with bacterial blight resistance and mid-late maturing property by the rice breeding team at NICS in 2015. The heading date of “Samkwang1” was August 8 in the middle plain area, which was 2 days early than that of “Hwaseong.” “Samkwang1” had a culm length of 77 cm, which was 7 cm shorter than that of “Hwaseong,” and it had 128 spikelets per panicle. The viviparous germination rate of “Samkwang1” was 2.1%. “Samkwang1” showed resistance to blast, bacterial blight (K1, K2, and 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 exhibits translucent and medium short grains. The cooked rice grains of “Samkwang1” have an excellent palatability index (0.35) and lower protein content (6.2%) than that of “Hwaseong.” The characteristics related to grain milling were better than those of “Hwaseong,” especially the head rice milling recovery ratio and head rice ratio (94.2%). “Samkwang1” showed 5.62 MT/ha of milled rice productivity at 11 sites under ordinary cultivation conditions (Registration No. 6798).

Cheongpum’, a japonica rice variety, was developed from a cross between Yeongdeog45 and ‘Samkwang’ by the rice breeding team at NICS in 2015. The heading date of ‘Cheongpum’ was August 10 in the middle plain area, which was two days later than that of ‘Hwaseong’. ‘Cheongpum’ had a culm length of 79 cm, which was 5 cm shorter than that of ‘Hwaseong’, and 116 spikelets per panicle. The viviparous germination rate of ‘Cheongpum’ was 27.9%. It showed resistance to blast, bacterial blight (K1, K2, K3 race), and stripe virus, but susceptibility 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 ‘Cheongpum’ had an excellent palatability index (0.41) and lower amylose content (18.8%) than that of ‘Hwaseong’. The grain milling characteristics were better than those of ‘Hwaseong’, especially the head rice milling recovery ratio and head rice ratio (94.1%). ‘Cheongpum’ showed 5.36 MT/ha of milled rice productivity at 11 sites under ordinary cultivation (Registration No. 6799).