This study was conducted to evaluate Korean rice cultivars to search any suitable varieties for the northern region of the Korean Peninsula (North Korea). A total of 92 rice varieties which included 74 bred cultivars from South Korea, 13 collections from North Korea and five local cultivars from China, were involved in the evaluating trials for their performance. Stability at three sites inthe northeastern areas of China, which are located in the northern border areas of North Korea, for three years from 2017 to 2019. The ecologically well-adapted rice varieties were selected at each trial site during the first year and employed again as the materials for the subsequent yield trials. A total of six varieties with relatively better performing and stability were selected through the subsequent trials at three sites for three years: Unkwang, Daejin and Taebaek at Dandong region; Hanseol and Taebong at Longjin region; Taebong and Namweon at Hunchun region, respectively. Dandong is located in the southeast parts of Liaoning, which has similar climatic characteristics to the west coastalregion of North Korea. Longjin is located in the middle-east parts of Jilin, which has also similar climatic characteristics to the northern inland region of North Korea. Hunchun is located in the northeastern parts of Jilin, which has presumably similar climatic characteristics to the northern part of the eastern coastal region of North Korea. Unkwang is characterized by its early maturity, with the heading at the 2nd of August, and reveals a yield potential of 7.11 T/ha with resistance to the blast (BL) and the bacterial leaf blade (BLB) diseases. It is predicted to be suitable for the northern area of the Suyang mountain region and the central inland region of North Korea. Daejin has asemi-early maturity heading around the 6th of August and yields of 6.06 T/ha with resistance to BL, BLB, and stripe virus (SV) diseases. Daejin will be adaptable to the northern area of Suyang mountain region. Taebaek is medium maturing variety of Indica/Japonica type. It is heading at the 14thof August with good ripening at maturity, and has yield potential of 6.84 T/ha with resistance to BL, BLB and SV diseases. It will be adaptable to the southern area of Suyang mountain region. Hanseol is early maturing, heading on the 3rd of August, and yields 6.44 T/ha with the short stature and cold tolerance (CT). It will be adaptable to the northern inland and mountainous regions of North Korea. Taebong is semi-early maturingwith the heading at the 6th of August and has a yield potential of 6.96 T/ha with cold tolerane and blast resistance. Taebong was also outstanding in theHunchun region, indicating a more or less wide adaptability in cold areas. It is expected to be adaptable to the northern inland region of North Korea as well as the northern part of the eastern coastal region. Namweon is a medium-maturing variety with aheading date of August 10, and a yield potential of 4.76 T/ha with cold tolerance and resistance to rice neck blast disease. It is expected to be adaptable to the northern part of the eastern coastal region.

1. 본 연구는 우리나라 북부지역과 중국의 북한 인접지역에서 동일 품종을 재배하여 다양한 기후조건에서도 출수일수 변이계수가 안정적이고 조숙성인 품종을 선정하여 북한 적응성이 높은 품종선발에 기초자료로 활용하고자 수행된 연구결과이다. 2. 북한 접경 국내외 6개소에서 출수일수별로 극조생종, 조생종, 준조생종, 중생종의 4개 출수생태형으로 분류하였다. 국내에서는 극조생종에는 9품종, 조생종은 42품종, 준조생종은 17품종, 중생종은 4품종으로 분류되었고 중국에서는 극조생종 7품종, 조생종 27품종, 준조생종 32, 중생종 9품종으로 구분되었다. 3. ‘수원’ 등 국내 3개소에서 출수기의 변이계수는 4.8~ 18.5%이었고 변이계수가 6.0 이하인 품종은 태봉, 내풍, 화동, 운장, 인월, 진봉, 운봉, 금영, 삼천 등 이었다. 4. ‘단동’ 등 중국 3개소에서 출수기의 변이계수는 국내보다 낮은 0.5~8.1%로 변이계수가 2.0 이하인 품종은 태성, 진부찰, 중모1001, 오봉, 새상주, 중모1011, 삼천, 남원, 길주1호(북한 수집) 등 이었다. 5. 한국과 중국의 6개소에서 출수기 변이계수는 8.7~13.3% 의 범위를 보였고, 변이계수가 9.0% 이하로 낮은 품종은 국내 육성 품종 둔내, 운봉, 화동, 진부찰, 설레미 품종으로 북한의 벼 재배지역에서 적응성이 높을 것으로 판단된다. 대비품중으로 북한 대비품종인 원산69호, 중국 대비품종인 길주1호 등도 변이계수가 안정적인 품종이었다.

‘화원5호’는 ‘일품벼’의 유전적 배경에 ‘모로베레칸’의 도열병 저항성 유전자가 이입된 근동질 계통을 육성하기 위해 ‘일품벼’와 ‘모로베레칸’을 교배하고, 계속적인 여교배와 MAS를 병행 실시하여 육성한 계통이다. ‘화원5호’는 ‘일품벼’의 유전적 배경에 염색체 1번, 4번 및 6번에 ‘모로베레칸’의 염색체단편이 이입된 것으로 나타났으며, 염색체 4번에 위치한 ‘모로베레칸’의 단편이 도열병 저항성을 증진시켰다. ‘화원5호’의 출수기는 보통기 재배에서 8월 19일로 ‘일품벼’와 동일한 중생종 품종이며, 천립중은 23.8 g으로 ‘일품벼’와 유사한 수준이었다. 완전미율은 ‘일품벼’에 비해 약간 낮았고, 아밀로스 함량은 ‘일품벼’보다 높았으나 통계적인 차이는 없었다. ‘화원5호’의 정조수량은 2005년부터 2006년간 실시한 생산력검정 시험에서 평균 6.53 MT/ha로 ‘일품벼’ 대비 102% 수준이었다. 4개 지역에서 2개년간의 밭못자리 검정 및 연계재배법을 이용한 도열병 검정 결과, ‘화원5호’는 ‘일품벼’에 비해 도열병 저항성이 증진된 것으로 나타났다. 생산력검정 시험 결과 조사된 형질 중 도열병저항성을 제외한 기타 형질에서는 ‘일품벼’와 유사한 근동질계통으로, 품종보호 출원 조건에 부합하여 ‘화원5호’로 명명하고 품종보호원을 출원하였다.

We conducted a QTL analysis of agronomic traits using 117 BC3F5 and BC3F6 lines developed from a cross between Ilpumbyeo and Moroberekan. Genotypes of 117 BC3F5 lines were determined using 134 simple sequence repeat (SSR) markers. A total of 832 Moroberekan chromosome segments with 410 homozygous and 422 heterozygous, respectively, were detected, and the genetic distance of introgression segments ranged from 0.5 cm to 112.1 cm. A linkage map constructed using 134 SSR markers was employed to characterize quantitative trait loci (QTL). The 117 BC3F5 and BC3F6 lines were evaluated for seven agronomic traits at two locations in 2006 and 2007 and at one location in 2007. A total of 26 QTLs were identified for seven traits including days to heading, and the phenotypic variance explained by each QTL ranged from 9.2% to 24.2%. Moroberekan alleles contributed positive effects in the Ilpumbyeo background at eleven QTL loci including panicle length and spikelets per panicle. Five QTLs, two for days to heading and one each for culm length, panicle length and spikelets per panicle were consistently detected in every occasions indicating that these QTLs are stable. Among them, two QTLs, spp6 for spikelets per panicle and pl6 for paniclel length were localized in the similar region. Increase in spikelets per panicle at this locus might be due to the increase in panicle length, because both traits were associated with increase in spikelets per panicle and panicle length due to the presence of the Moroberekan allele. These Moroberekan QTLs might be useful in breeding programs to develop high-yielding cultivars.

Grain weight (GW) or grain size is the most important target not only as a major component of grain yield, but also associated with the cooking quality in rice breeding program. In a previous study, two loci for grain weight, gw8 and gw9, have been fine map to about 306.4kb and 37.4kb, respectively, in backcross populations derived from a cross between the Korean japonica cultivar Hwaseongbyeo and Oryza rufipigon (IRGC 105491). Both O.rufipogon alleles increased GW in the Hwaseongbyeo background despite the fact that O. rufipogon was the small-seeded parent. To test the effect of pyramiding the QTLs for grain weight, an F2 population consisted of 226 individuals was developed derived from the cross between the two QTLs (gw8 and gw9), and used MAS to select nearly isgenic lines for two QTLs and a pyramiding line. Molecular genotyping of F2 population revealed the existence of interaction between gw8 and gw9. Moreover, the interaction was also confirmed by phenotypic analysis of four QTL-NILs. The results suggest that epistasis interaction is important genetic basis in determining yield traits in rice.