서남부간척지 벼 담수표면 직파재배시 합리적인 질소기비시용시기와 시비량을 구명하고자 세사양토(문포통, 염농도0.1~0.2%)에서 동진 2호를 공시하여 시험한 결과를 요약하면다음과 같다. 4월 중순에 담수표면직파재배에서 파종전 기비시용시 적정입모수가 확보되었으나, 파종 후 10일, 20일 및 30일에 기비를 시용한 경우에는 적정입모수가 확보되지 않아 수량감소가컸다. 파종전 기비 시용 처리시 m2당 입모수는 163개이었으나파종 후 10, 20, 30일 기비시용 처리에서는 m2당 평균 98개로 파종전 기비시용에서 입모수가 많았다. 수량은 파종전 기비 시용 처리에서는 10a당 523 kg이었으나,파종후 10, 20, 30일 기비시용 처리에서는 10a당 평균433 kg로 파종전 기비 시용 처리에서 파종후 기비 시용처리보다 수량이 증수되었다. ha당 질소시비량 200 kg에서 쌀수량이 10a당 541 kg으로 처리간 수량이 가장 많았으나 질소시비량 170 kg/ha에서도 질소시비량 200 kg과 통계적 유의성이 인정되지 않았다. 따라서 서남부간척지에서 담수표면직파재배를 할 때의 기비시용 시기는 입모확보 및 쌀 수량과 염해 등을 고려해 볼 때파종전에 기비를 시용하는 방법이 파종후에 기비를 시용하는방법보다 좋을 것으로 보이며 또한 질소시비량을 표준시비200 kg/ha 보다 적은 170 kg/ha로 시용해도 적당할 것으로 생각된다.

Currently, more than 33 resistance gene against bacterial blight(BB) have been identified and used to develop resistant cultivar. IRRI developed near isogenic lines carrying monogenic resistance gene and pyramided genes, IRBB lines. This study was conducted to identify the response of resistance gene to Korean bacterial blight races(K1, K2, K3, and K3a) in IRBB lines. Xa1(IRBB1) was resistant to K1 race and Xa2(IRBB2) was resistant to K1 and K2 race. Xa3(IRBB3 and IRBB203) exploited in many breeding programs in Korea were resistant to K1, K2, and K3 race but susceptible to K3a. Xa4(IRBB4 and IRBB204), xa5(IRBB5 and IRBB205), Xa7(IRBB7 and IRBB207) were resistant to four races. xa8(IRRR8) and Xa11(IRBB11 and IRBB211) showed same reaction of Xa2, resistant to K1 and K2. Xa10(IRBB10 and IRBB210), xa13(IRBB13), Xa14(IRBB14 and IRBB214) showed same reaction of Xa1, resistant to K1. Xa21, identified from the wild rice, Oryza longistaminata, is highly resistant to a broad spectrum of Xoo races. In this study, Xa21 was resistant to K2, K3, and K3a but susceptible to K1 widely spreading in Korea. So, Xa21 may be vulnerable to Korean bacterial blight. But pyramided lines with Xa21 showed high level of resistance to all races of Korea. Pyramided lines with Xa4 which conferred durable resistance in many commercial rice cultivar, xa5 which provides recessive resistance, and other resistance genes showed high level of resistance to Korean bacterial blight races.

Hopum is a new japonica rice cultivar developed from the cross between Milyang165 and F1 crossing Milyang165 and Iksan438 at Department of Rice and Winter Cereal Crop, NICS, RDA, in 2006. This cultivar has a short grain shape and about 141 days growth duration from direct seeding to harvesting in the southern plain including Chungcheong province. This cultivar has short culm and spikelet number per panicle is similar to that of Nampyeongbyeo, while filled grain rate is lower than standard variety. This cultivar has medium size of brown rice and shows moderate resistance to leaf blast, to bacterial blight pathogens of K1, K2 and K3 and stripe virus disease but susceptible to major virus diseases and insect pests. The milled kernel of Hopum is translucent with non-glutinous endosperm. Protein and amylose content of Hopum is about 6.5% and 18.7%, respectively. This cultivar has better palatability of cooked rice than Chucheongbyeo harvested in Gyeongki province. Its milling recovery (76.8%) and percentage of perfect-shaped milled rice (94.7%) were higher than Nampyeongbyeo. The milled rice yield of Hopum was 5.83 MT/ha (15% higher than Juan) under wet-direct seeding, 5.66 MT/ha (8% higher than Juan) under dry-direct seeding, and 6.00 MT/ha (8% higher than Nampyeong) under ordinary transplanting cultivation. “opum”would be adaptable for ordinary transplanting and direct seeding in the southern plain including Chungcheong province.