Experiments were conducted to find out the optimum level of slow release N fertilizers when total amounts of nitrogen required throughout the growing season in paddy were applied in the soil of seedling box. To evaluate the emergence rate and growth of rice seedlings, five levels of Meister (MS) 10, MS S10, and latex coated urea (LCU) which are equivalent to 0, 40, 60, 80, and 100kg N h a-l were mixed in soil of the seedling box. Emergence rate differed depending on the fertilizers and N levels; in MS 10 plots the emergence rate was 40.8% at 40kg N h a-l and no seedlings were emerged at the higher levels, in MS S10 plots higher than 80% at all the N levels, and decreased with the N levels from 70.0% at 40 kg N h a-l to 59.5% at 100kg N h a-l of LCU. Seedling started to wilt at 40 kg N h a-l of MS 10 and 80 and 100 kg N h a-l N of LCU on the 8th day after sowing, while seedling growth was normal at all the levels of MS S10. Field performance of rice was evaluated at the 0, 30, 60, 90, 120kg N h a-l of MS S10 applied in the soil of seedling box and N was not applied in paddy. Grain yield at 90 and 120kg N h a-l of MS S10 was similar to conventional urea split application (120 kg N h a-l ), but significantly higher compared to 30 and 60kg N h a-l of MS S10. Fertilizer N recovery decreased with N levels and the N recovery at 90 kg N h a-l of MS S10 and conventional urea split application were 62.2 % and 44.2%, respectively, with similar grain yield. The optimum level of MS S10 to be applied in seedling box seems to be about 90 kg N h a-l considering grain yield, price of fertilizer, labor applying fertilizer, and fertilizer N recovery.d fertilizer N recovery

벼 어린모 육묘시 적기이앙을 못하여 육묘일수가 연장 될 경우 모소질과 본답초기 생육 및 수량에 미치는 영향을 검토하고자 화성벼를 공시하여 1997년 작물시험장 포장에서 8일모, 12일모, 16일모, 20일모를 이용하여 시험을 수행한 결과는 다음과 같다. 1. 성묘을은 8일모가 93.9%로 가장 높았으며, 12일모는 88.9%, 16일모는 82.0%, 20일모는 80.8%로 육묘일수가 길어질수록 성율이 낮아졌다. 2. 이앙당시 초장이 8일모가 7,6cm, 12일모가 13.0cm, 16일모가 15.1cm, 20일모가 16.9cm로 육묘 12일 이후는 육묘일수 지연에 따른 생육 차이가 적었다. 3. 종자내 배유양분 잔존율은 8일모가 52.5%로 가장 많았으며 12일모가 36.2%, 16일모 30.1%, 20일모가 27.4%였다. 4. 결주율은 8일모와 12일모는 5.1-5.2%로 비슷하였으나 16일모와 20일모는 6.7%, 7.8%로 결주 발생이 많았다. 5. 발근량은 8일모가 104.0로 가장 높았으며, 다음은 12일모로 59.5, 16일모는 41.4, 20일초는 27.9였다 6. ha당 쌀수량은 육묘일수가 길어질수록 수량감소가 현저하여, 8일모 대비(6.18톤) 12일모는 5%, 16일모는 11%, 20일 모는 16%가 감소하였다. 7. 현미의 완전미 비율은 8일모와 12일모는 92.1, 91.5%로 비슷하였으며, 16일모와 20일모는 88.8, 85.4%로 현저히 감소되었다.

In order to develop more stable seedling stand method in wet direct rice seeding culture, the effect of making the drainage ditches was studied in both methods of broadcast seeding on floody paddy surface and puddled-soil drill seeding. In a broadcast seeding on floody paddy surface, the ditching after seeding using a tractor or small ditch maker improved the seedling stand, and reduced the floating seedling and herbicide injury by accelerating the drainage. Suitable ditching time was at 2 days after seeding (DAS) for the tractor and at 3 DAS for the ditch maker. In the puddled-soil drill rice seeding culture, the ditching before seeding with a ditch maker at 3 days after draining effectively improved the seedling stand due to quick draining through well formed the seeding furrows. In the puddled-soil drill seeding, seedling stand number showed higher in both ditching plots synchronized with seeding compared with both only draining treatment at 1 DAS without ditching and the flooding plot condition for 6 DAS. And the suitable ditching depth was 6 cm, as considered the ditching status and drained status. These results suggest that the ditching in wet direct rice seeding is an resonable practice for improving the seedling stand through the accelerating drainage of field.

Rice seedling test was conducted to check the loging tolerance at ripening stage through evaluating the root characters. Thirteen Korean and foreign rice cultivars with direct seeding adaptable or high quality characteristics were grown in a cell pot and under submerged paddy. The root characters and pushing resistance of rice hill were determined at seedling and ripening stage, respectively. The diameter of crown root at the 7th and 8th leaf stages was thicker in lodging tolerance cultivars than those of others and showed significant-positive correlation with both pushing resistance and crown root diameter of mature plants. Also, the tensile strength of crown root at the 7th and 8th leaf stage showed highly positive correlation with the tensile strength of crown root of mature plants. The number of crown root at 7th leaf stage was significant-positively correlated with that of mature plant. The diameter of seminal root was not significantly correlated with the diameter of crown root throughout the whole growth stage. These results indicate that the diameter, tensile strength and number of crown root associated with root lodging tolerance can be detected with the seedling at about 7th or 8th leaf stage, and the seedling test using the cell pot is an useful and practical method to select lodging tolerant cultivars or lines of rice based on root characters, especially diameter of crown root.

To examine the seedling stand and growth as affected by early seeding dates of dry direct seeded rice in the Honam plain area of Korea, Dongjinbyeo was seeded at six seeding dates from early March to late April in rice fields of silty loam soil(Jeonbuk series) at the National Honam Agricultural Experiment Station (NHAES) for two years, 1996 and 1998. Seedling stand decreased slightly. with an early seeding date, but it produced more than the optimum seedling number except for the seeding of 25 March in 1996. Days to emergence was significantly longer, as seeding date was earlier, and days to emergence by early seeding was shortened only by 8 days because the mean air temperature was lower in 1996 than average, while in 1998, the reduction effect was nine to twenty five days because the mean air temperature was higher than average. In early seeding, various weeds occurred at the emergence date of rice and dominant weeds were Alopecurus aequailis, Ludwigia prostata and Rorippa islandica. NH4 + -N content in the soil at the 5th leaf stage and maximum tillering stage were lower, as the seeding date was earlier when nitrogen was split applied as basal and top dressed in 1996, while it was not significantly different among seeding dates when nitrogen was intensively applied as a top dressing in 1998. Tiller number at the maximum tillering stage and panicle number/m2 were more, as seeding date was earlier in 1996, while it was not different in 1998. Filled grain rate and 1,000 grain weight was not different among the seeding dates. Milled rice yield was significantly decreased in the seeding before the middle of March, but in the seeding after late March, it was not varied when compared with the normal seeding date in 1996, while in 1998, there was no difference among seeding dates. From the above results, in consideration of seedling stand, weed occurance, rice growth and milled rice yield, the critical optimum early seeding time in the southern plain area may lie in early April. But it was suggested that when soil moisture is proper for seeding practices, seeding amount is increased and nitrogen is applied after plumule emergence of rice, milled rice yield may not be reduced in the seeding of middle or late March, compared with the seeding in April.l.

Unstable seedling stand establishment of wet direct seeding culture of rice is one of the major elements preventing the extension of its culture area. In order to develop methods of seedling stand improvement in direct seeded rice on flooded surfaces, three field experiments were conducted on silty loam soil using a cultivar 'Donjinbyeo' for three years, mainly focusing on water management after seeding and seed soaking with plant growth regulators (PGRs). Under the condition of shallow flooding after seeding, seedling stand rate increased and floating seedling rate decreased in both early and normal season seeding compared to deep flooding. With earlier draining time after seeding, there was a tendency towards preferential growth of the seminal root, increase of seedling stand and decrease of the floating seedling rate. Therefore the highest seedling numbers per unit area and the lowest floating seedling numbers were found upon drainage at 1 day after seeding (DAS), while a contrary tendency was shown upon conventional drainage at 7 DAS. Seed soaking with PGRs such as Metalaxyl or mixing of Metalaxyl with gibberellic acid (GA3 ) significantly increased the seedling stand. In addition the effects of PGR treatment on seedling stand and the early growth of plants were greater under flooded conditions than under drained conditions after seeding, although draining of water after seeding improved the seedling establishment rate more when compared with the PGR treatment. These results suggest that draining management after seeding or maintaining of shallow flooding for a week is the most effective method to improve the seedling stand rate in wet direct seeding.

priming; rice seed; SEM; embryo; starch granule; α -amylase; sugar

Three rice cultivars, Namweonbyeo (early maturing), Hwaseongbyeo (medium maturing) and Dongjinbyeo (medium-late maturing) were trans-planted with 3 different seedling ages to investigate their growth habits and to improve the cultural method in paddy fields in the southern plain area of the Honam region in 1993. The 10-day old seedlings had more vigorous elongation of plant height and higher tillering ability but lower effective tiller rate, when compared with 35-day or 40-day old seedlings. Leaf area index and top dry weight were lower in 10-day old seedlings up to 40 days after transplanting but thereafter, were not different among seedlings ages. CGR was later in 10-day old seedlings, up to 30 days after transplanting, but in 30 to 40 days after transplanting, it was reversed. RGR was the highest in infant seedlings to 40 days after trans-planting, while in 50 days after transplanting, it was reversed. Panicle number and spikelet number per square meter were the highest in 40-day old seedlings, next highest in 35-day old seedlings and the lowest and in adult seedlings up to 40 days after transplanting, while spikelet number per panicle was vice versa. Milled rice yield did not vary significantly by seedling ages, but among the varieties, it was less in Hwaseongbyeo compared with Naweonbyeo and Dongjnbyeo.

본 실험은 볍씨에 염화망간의 농도를 2500, 3500 및 4,500ppm을 처리하여 벼의 초기생육에 대한 생육반응, 엽록소 함량, 유리 proline 및 SOD활성변화를 자포니카형인 일품벼를 실험재료로하여 실험한 결과를 요약하면 다음과 같다. 1. 근장은 무처리보다 망간농도 4,500ppm에서는 0.3cm로 망간농도가 증가할수록 뿌리 생장이 억제되었다. 2. 발아율은 망간농도 3,500ppm에서 68%였으나 망간농도 4,500ppm에서 는 43%로 가장 낮았다. 3, 엽록소 함량은 무처리보다 고농도인 4,500ppm 에서 1.16mg으로 가장 낮았다. 4. 유리 proline 함량은 무처리에서는 발아 후 3일과 8일에서 큰 차이를 보이지 않았고 발아 후 3일째 망간농도2,500ppm과 4,500ppm에서 각각 3,286μmole과 5,872μmole로 망간농도가 높아질수록 유리 proline 함량이 증가하였다. 5. SOD 활성은 발아 후 2일째 무처리가 762EU인 것에 비해 망간농도 4,500ppm에서는 1,693EU로 가장 높았다.

These experiments were conducted to investigate water uptake, electrical conductivity, germination percentage, seedling growth, and seedling establishment rate in direct seeding cultivation of rice. The rice seeds of six japonica type varieties were coated with 12 kinds of polymers in a standard concentration of 0.2% using seed coating machine. The water absorption of the polymer-coated seeds under saturation conditions was not different among varieties, and was the highest in kulcel, maltrin, and waterlock on the polymer-coated seeds. The electrical conductivity with waterlock (55.0 ~mu scm-1g-1 ) was higher than the control plot (45.6 ~mu scm-1g-1 ) and other treatments. The germination of the polymer-coated seeds was 95.9% at control plot, 92.7% at low temperature and 35.7% at high temperature. The total dry weight of seed decreased in the order of low temperature, control plot, and high temperature, and was effective in pvp (polyvinyl pyrrolidone), opadry, and sacrust. The seedling establishment rate in direct seeding cultivation ranged from 74.9 to 81.0% in flooded paddy surface, and ranged from 64.7 to 76.6% in dry paddy. In both cases, it decreased in the order of early, medium and medium-late varieties, but was enhanced in daran 8600, sepirect, and sacrust. According to this study the recommended polymers for direct seeding cultivation of rice are daran 8600, sepirect, and sacrust

An experiment was carried out to find out the priming effects of rice seeds, Oryza sativa L. (cv. Ilpumbyeo) on. the seedling establishment and early emergence under excess soil moisture conditions. Seeds were primed by soaking in -0.6 MPa polyethylene glycol (PEG) solution at 25~circC for 4 days. The primed seeds were sown in soils with various soil moistures (60, 80, 100, 120, and 140% field capacity) at 17 and 25~circC , respectively. Germination and emergence rates, plumule height, and radicle length of primed seeds were higher than those of untreated seeds at any soil moisture and temperature examined. The time from planting to 50% germination (T50 ) of primed seeds was less than that of untreated seeds by 0.9～3.7 days. Germination rate, emergence rate, plumule height, and radicle length were highest at the soil moisture of 80% field capacity among the soil moistures. Priming effects of rice seeds on germination and emergence rates were more prominent under the unfavorable soil moistures (60, 100, 120, and 140% field capacity) than those under the optimum soil moisture condition (80% field capacity). However, priming effects on seedling growth were greater at near optimum soil moisture compared with too lower or higher soil moistures. Therefore, these findings suggest that priming of rice seeds may be a useful way for better seedling establishment under the adverse soil conditions.

벼 품종 안중벼를 공시하고 조류 기피제인 methiocarb을 여러 가지 제형으로 제조하고, 약량을 달리하여 최아 볍씨에 처리한 후 새 피해, 초기 생육 및 약해를 조사한 결과를 요약하면 다음과 같다. 1. <시험 1> Methiocarb 제형별 새 피해 경감 효과와 모의 생육 1) Methiocarb의 처리는 제형과 약량에 관계없이 새에 의한 피해가 없었으나 무처리구는 5일후에 30％, 10일 후에 85％, 15일 후에는 100％의 피해를 입었다. 2) 입모율은 처리간 유의한 차이가 없었으나, 파종 15일 후의 초장과 잎수는 methiocarb 15g 처리구에서는 methiocarb 10g 처리구에 비하여 유의하게 작아서 약해가 있었다. 3) 파종 35일 후 약해에 대한 회복 상태를 보면 methiocarb＋thiram 15g 처리구는 초장이 유의하게 작았으나, methiocarb FS 15g처리구 초장은 무처리구와 큰 차이가 없었다. 2. <시험 2> Methiocarb 제형의 벼 종자 분의에 의한 본답 시험 1) Methiocarb 처리구는 무처리구에 비하여 새 피해가 유의하게 경감되는 것으로 나타났다. 2) 파종 25일 후의 초장과 잎수는 모든 처리구에서 유의한 차이를 보이지 않았다. 3) 파종 10일 후에는 약제 처리구는 경후한 약해가 발생하였으나 파종 20일 후에는 무처리구와 큰 차이가 없었다.

벼 담수토중직파시 산화제 종자분의에 의한 초기 출아입모 향상 효과를 시험한 결과를 요약하면 다음과 같다. 1. 산화환원전위차는 무처리가 가장 낮게 경과하였으며, KNO3 가 대체로 높으면서 산화 기간이 오래 지속되었던 반면 CaO2 는 타처리에 비해 약간 낮게 경과하는 경향이었고, 산화제처리로 출아기간동안 종자주위의 토양환원억제에 상당한 영향을 미쳤다. 2. 토양 pH변화는 무처리에서 7이상으로 가장 높게 경과하여 논토양의 환원된 상태를 보였으며, 산화제 처리구에서는 초기에 낮았다가 점차 높아지는 경향을 보였으나 무처리보다 낮아 일시적으로 토양을 산성화 시키는 효과를 보였다. 3. 입모수는 CaO2 가 파종후 8일경에 60%이상의 출아율을 보였고, 특이산성토 처리는 CaO2 보다는 낮았지만 무처리에 비해 입모율은 많이 향상되었다. 4. 초기생육에서 초장은 처리간 차이가 인정되지 않았고, 엽령차이는 CaO2 및 특이산성토에서 7.6매로 무처리의 6.2매에 비하여 1.4매 정도 많아 잎의 전개가 더 빨랐으며 근장 또한 CaO2 분의종자에서 10.2cm로 가장 길었고, 경수는 CaO2 와 특이산성토 피복종자에서 가장 많았다. 5. 본 실험에서 CaO2 는 입모가 균일하고 출아 소요 기간도 짧아 담수토중 직파재배에서 벼 종자 분의 재료로 가장 우수하였으며, 특이산성토분의에서도 양호하여 그 가능성을 검토할 수 있었다.

본 실험은 벼 종자에 Al을 0, 300, 600 및 900ppm으로 처리하여 발아중 Al에 대한 벼의 초장, 근장, 발아율 등의 생육특성, 엽록소 함량, 전분, 당 및 유리 proline함량 등의 변화를 일품벼와 향미벼 001를 공시하여 검시한 결과를 요약하면 다음과 같다. 1. 초장과 근장은 Al의 농도가 증가할수록 신장이 감소하였는데 뿌리의 신장억제가 보다 현저하였다. 발아율은 일품벼와 향미벼 001 모두 Al의 농도가 증가함에 따라 발아율의 급격한 감소를 보였다. 2. 엽록소 함량은 품종간 뚜렷한 차이를 보였고 두 품종 모두 Al의 농도가 증가할수록 함량이 감소하는 경향을 보였다. 3. 식물체의 전분과 당함량은 Al 처리시 대조구에 비해 함량이 감소하였다. 4. 식물체의 중금속과 무기성분의 함량은 일품벼에 있어 무처리보다 Al의 농도가 증가함에 따라 Al 600ppm까지는 식물체내의 중금속 축적이 증가하다가 Al 900ppm에서는 오히려 감소하는 경향을 보였고, Ca, Mg, Fe 및 Mn의 식물체내의 함량은 두 품종 모두 Al 처리시 무처리에 비해 Al 처리시 급격한 증가를 보였다. 5. 무처리에 있어서는 발아일수별로 proline함량이 차이가 없었으나 Al 처리의 경우 발아후 1일째는 Al의 농도가 증가함에 따라 유리 proline의 함량도 증가하였고 특히 처리 후 3일째에는 급격한 함량의 증가를 보였다.

수도의 내염성 품종 안나프르나에 NaCl 50 mM을 처리하여 유도된 단백질의 분리정제를 수행하여 한 개의 새로운 단백질을 분리 정제하였다. 그 결과는 다음과 같다 1. 10일된 유묘에 50mM NaCl을 48시간 처리하여 유도된 단백질의 존재를 전기영동을 통하여 확인하였다. 2. FPLC를 이용한 DEAE와 phenyl column을 이용하여 순수한 정제가 가능하였고, 이 과정을 통하여 전기영동상에서 단일 밴드를 나타내는 하나의 단백질을 정제하였다. 3. 이 단백질의 분자량이 64,000이라는 것을 Se-phdex-G 100 column chromatography를 통하여 확인하였다. 4. 이 단백질에 대한 단일 항체를 조제하여 고역가 항체를 분비하는 hybridoma 세포주 3개를 작성하고 isotype등 특성을 조사하였다.