• 한국작물학회지
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• 제44권1호
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• pp.11-19
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• 1999

This experiment was conducted with nine wheat geno-types to choose the wheat which has excellent early vigour. 'Vigour 18' and 'ZL 59A' are excellent in the long coleoptile genotype, while 'Amery' and 'Janz' are excellent in the short coleoptile genotype. Responding to the growth stage and nitrogen level, Vigour 18 is predominant in the long coleoptile genogype, while Janz in the short coleoptile genotype. Responding to sowing density and nitrogen level, the higher the sowing density was, the shorter the leaf area of Vigour 18 and Janz. Also the leaf area turned out to larger in the plot fertilized with high nitrogen than in the plot fertilized with low nitrogen. This is true of leaf weight and root weight. Concerning specific leaf area (SLA) and leaf area ratio (LAR), the higher the sowing density was, the SLA tended to grow larger, while the SLA grew larger in the plot fertilized with low nitrogen, as were found in Vigour 18 and Janz. The roots of long coleoptile genotype, Vigour 18, turned out to grow longest on the plot sown with 3 seeds. While the roots of short coleoptile genotype, Janz, grew longest on the plot sown with 2 seeds. The relative growth rate (RGR) was the same at low N rates and high N rates. The RGR was 0.071 and 0.072 g $g^{-1}d^{-1}$ at low N rates and high N rates. The partitioning of RGR into net assimilation rate (NAR) and LAR showed that the average LAR at low N rates was similar to the LAR at high N rates. Variation within each cultivar in the LAR and NAR was small relative to the difference between them at low N rates and high N rates. Above ground mass was 8.2 mg greater at high N rates than low N rates, whereas leaf area was 0.05 $\textrm{m}^2$$kg^{-l}$ greater at high N rates than low N rates. The NAR was similar at low N rates and high N rates, whereas LAR was greater at high N rates (0.05 $\textrm{m}^2$$kg^{-l}$); variation in SLA was responsible for the variation in NAR and LAR both at low N rates and high N rates. NAR was more closely associated with the reciprocal of SLA.

• Journal of Forest and Environmental Science
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• 제38권4호
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• pp.256-262
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• 2022

The timing of seed harvesting is an important decision in the management of seed orchards because it affects seed quality and yield. To investigate the effect of cone harvest time on seed quality and determine the optimal harvesting time, cones were regularly collected in seven times and germination tests were performed at each harvest time in two clonal seed orchards of Chamaecyparis obtusa. As cones developed, the percentage of seed germination increased before cone moisture content began to decrease significantly. The moisture contents of cones were highest at the first collection as 68.3% and 67.3% in Jeju and Gochang seed orchards respectively. At this time, germination speed was slowest, indicating poor seed vigour. The highest germination was found at the second stage in Jeju (36.5%) and at the seventh stage in Gochang (28.6%) seed orchard. The germination speed increased as cone moisture content decreased. Additionally, changes of seed vigour differed among the developmental stages in both seed orchards. Consequently, the optimal cone harvest time of C. obtusa seed orchards in Jeju was early September when high germination percentage was obtained. In Gochang seed orchards, late October was optimal cone harvest time when the germination speed was fast and the cone moisture content decreased.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.103-103
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• 2017

Vigorous root growth at the seedling stage in dry direct-seeded conditions is considered as a critical trait because it is involved in seedling emergence, early vegetative vigour, nutrient uptake as well as drought tolerance. In this study, we performed QTL mapping using the recombinant inbred lines obtained from the cross between Tongil-type Dasan and temperate japonica TR22183 (DT-RILs) to identify QTL underlying early root development. TR22183, which was previously reported to have high nitrogen utility and cold tolerance, showed vigorous root growth at the seedling stage in semi-drought conditions. Root length, fresh weight and dry weight of TR22183 were significantly higher than in Dasan. By QTL analysis with genotyping-by-sequencing method, we identified two QTLs for root fresh weight (RFW) in chromosome 7 and root dry weight (RDW) in chromosome 8, explaining phenotypic variances of 13.5% and 10.6%, respectively. These QTLs would be used to develop rice varieties adapted to direct-seeded cultivating system.

• 한국초지조사료학회지
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• 제22권1호
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• pp.69-76
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• 2002

동일한 토양명(송정통)을 갖는 인접한 토양에서 신개간 토양과 다소 숙전화 된 기경작 초지토양간의 비옥도 특성과 시비처리별 목초 생산성과 무기양분 함량차이를 비교.검토하고자 기초시험으로 pot 시험을 수행하였다. 초지토양의 비옥도 개량에 필수적인 퇴비(I보), 석회(II보) 및 인신(III보)의 시용효과를 단계별로 비교.검토하였다. 본보에서는 3요소 및 고토를 동일하게 기본시비를 한 조건에서 1) 무퇴비구, 2) 퇴비시용구(1,200kg/10a기준)를 처리내용으로 한 두 토양간 퇴비의 비효를 비교.검토하였다. 1. 시험전 두 토양간 토양의 화학성(비옥도) 에 큰 차이를 보였다. 초지토양 비옥도 등급기준(불량-보통-양호)에 기준 한 두 토양간의 차이를 비교하여 보면(신개간지 토양 ↔ 기경작 초지토양); pH, Ca과 Mg 함량은 불량 ↔ 보통, 유효인산 함량, 염기포화도 및 염기비는 불량 ↔ 양호, K 함량은 보통 ↔ 양호, 인산 흡수계수는 양호 ↔ 양호, 양이온치환용량은 불량 ↔ 약간불량 수준을 보였다. 시험 후 유효인산 함량은 두 토양 공히 무퇴비구보다 퇴비 시용구에서 뚜렷한 차이를 보이며 개량효과가 높았다. 신개간지 토양에서 퇴비 시용으로 CEC상승효과가 크게 나타났다. 2. 목초의 초기 생육상은 신개간 토양보다 기경작 초지토양에서 매우 양호하였으며, 초기 생육상에 미치는 퇴비의 시용 효과는 신개간 토양에서 크게 나타났고, 반면에 기경작 초지토양에서는 차이가 나타나지 않았다. 3. 무퇴비구에서 기경작 초지토양의 목초수량이 신개간 토양보다 50.9% 더 높은 목초 생산성을 보였다. 신개간지는 퇴비 시용으로 17.1% 증수하였고, 반면에 기경작 초지는 7.6% 증수효과를 보였다. 상대적으로 신개간지 토양에서 퇴비의 시용 효과가 더 크게 나타났다. 4. 기경작 초지토양의 목초 중 Ca, Mg, P 함량이 신개간 토양의 목초 중 함량보다 확연히 높았으나 K 함량은 큰 차이를 보이지 않했다. 신개간지 토양의 목초 중 Mg과 P 함량은 무퇴비구 보다 퇴비시용구에서 약간 높은 함량을 보였다.

• 한국작물학회지
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• 제43권4호
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• pp.214-222
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• 1998

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 $\mu scm^{-1}g^{-1}$) was higher than the control plot (45.6 $\mu scm^{-1}g^{-1}$) 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.

• 한국초지조사료학회지
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• 제13권2호
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• pp.99-104
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• 1993

With a purpose of finding out the effects of phosphatic fertilizer application at the grassland establishment and management on the dry matter yield and quality of grasses, a field experiment was arranged with four treatments as a randomized complcte block design and lasted from September, 19 89 to October, 1991 in hilly area near Suwon. The results obtained are summarized as follows: 1. As a early plant growth. winter hardiness. growth vigour and coverage of grasses of the plots with phosphatic fertilizer were better than those of the plots without $P_2O_5$. and the effect of application at the management was much better than that at the establishment of grassland. 2. The effect of phosphatic fertilizer on DM yield of legume was higher than of grass. Total DM yield with phosphatic fertilizer at the only establishment (5.688 kg/ha). at the only management (8.014 kg/ha) and at both the establishment and management of grassland (1 1,082 kg/ha) was much more increased by 38, 95 and 169% than that without phosphatic fertilizer (4.1 19 kg/ha), respectively. 3. The chemical component of crude protein and crude fat with phosphatic fertilizer was a little higher, on the other hand, content of NFE was lower than that without $P_2O_5$ fertilization, but the contents of crude fiber and crude ash did not tend to differentiate between treatments. 4. Production of encrgy(TDN, StE and NEL) with phosphatic fertilization at the establishment and the management of grassland was appeared to increase by 34 to 390h and 72 to 99% than that without $P_2O_5$, respectively. Production of curde protein with $P_2O_5$ tended to be similar to production of energy.

• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1318-1328
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• 2011

The tropics is not an ideal location for calf rearing as the high temperatures and humidities introduce many potential disease problems to milk fed calves. In addition, the type of dairy farming (generally poorly resourced small holder farming) and the general lack of awareness of the long term implications of poorly reared stock do not encourage farmers to pay close attention to their calf and heifer rearing systems. Surveys of calf rearing systems in Asia, tropical Africa and South America highlight the high calf and heifer mortalities. A range of 15 to 25% pre-weaning calf mortality is typical on many tropical dairy farms. It is often as high as 50%, indicating very poor calf management. This contrasts with US findings of less than 8% mortality from birth to 6 months while surveys of Australian farmers report only 3% losses. Simple extension programs on farms in Sri Lanka and Kenya have drastically reduced calf mortalities and improved pre-weaning growth rates. Improved management strategies leading to lower calving intervals, higher calving rates, reduced still born and pre-weaned calf mortalities and fewer non pregnant heifers can supply many more dairy herd replacements than currently occurs. Such strategies can increase the number of replacement heifer calves in the herd from 15 to over 35%, thus allowing farmers to increase their herd sizes through natural increases. Simple management procedures such as ensuring adequate intake of good quality colostrum within the first 12 hours of life, housing and good hygiene to minimise disease transfer, providing clean drinking water, developing appropriate feeding protocols to encourage early rumen development and paying closer attention to climate control and animal health can all lead to improved calf vigour and performance. Good record keeping is also important so farmers can more easily identify susceptible calves and quickly treat potential problems.

• International Journal of Industrial Entomology and Biomaterials
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• 제26권1호
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• pp.22-30
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• 2013

The reproductive performance of multivoltine breed 'Nistari' and bivoltine breeds as NB18, P5 and a bivoltine hybrid (NB18 ${\times}$ P5) of B. mori were studied in different seasons in terms of total number of eggs laid, unlaid and hatching efficiency of the laid eggs to critically assess the breeds / hybrid potentiality. The bivoltine hybrid showed better performance in all the seasons as compared to the breeds investigated, as expected due to possibility of hybrid vigour. Among the breeds, bivoltine P5 had a better egg laid performance in S1 (February - March), S2 (May - June) and S3 (September - October) seasons but with an increase in the number of unlaid eggs. The hatching percentage, although didn't show any definitive trend, still suggested a marginal better performance in the hybrid. Most importantly, egg laying rhythmicity was studied by mating the female moth at 6.00 a.m. for $3{\frac{1}{2}}$ hours, and subsequently allowing the laying of eggs both under BOD condition ($25{\pm}1^{\circ}C$ and $85{\pm}5%$ RH) and at ambient temperature ($23-28^{\circ}C$ and $74.7{\pm}5%$) separately. Maximum (90%) egg laid occurred from 3.30 to 7.30 pm (i.e. 4 - 6 h after decoupling). Similar laying patterns were observed when females where mated at 12 noon and decoupled at 3.30 pm, revealing that late photoperiod and early scotoperiod were favourable for egg laying in case of multivoltine breed and bivoltine prefers late photoperiod for egg laying.

• 식물병연구
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• 제17권2호
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• pp.228-231
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• 2011

2008년부터 매년 전라남도 고흥군에 위치한 비파나무 묘포장에서 잎에 점무늬 증상이 관찰되었다. 전체 묘목의 50% 이상에서 이러한 증상이 나타났으며, 결국 잎이 일찍 떨어지고 수세가 약화되는 피해가 나타났다. 병반으로부터 관찰된 균은 Entomosporium mespili로 동정되었다. 이 균은 단포자 분리되어 KACC 44727 균주로 보존되었다. 인공접종 실험을 통하여 병원성을 검정하여 코흐의 원칙과 일치하였다. 따라서 국내에 비파나무 점무늬병을 처음으로 보고한다.

• Journal of Forest and Environmental Science
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• 제34권3호
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• pp.199-208
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• 2018

Quercus floribunda (Tilonj oak) is among the five species of Quercus and an evergreen tree found in Kumaun Himalayan region. Timing of germination is a crucial event determining the success of seedling establishment and survival. The aims of the study were to investigate the effect of sowing date on the germination and morphological responses of Tilonj oak (Quercus floribunda), cultivated during the month of August-September, with supplementary irrigation. The experiment was conducted by sowing seeds at two dates with one month interval in glass house conditions at DSB Campus, Nainital, Uttarakhand, India. Present study revealed that higher germination percentage (46.67 %) was recorded at sowing time $S_2$ as compared to the sowing time $S_1$ (32.86 %). Germination percentage as well as seedling growth were affected by sowing date though the differences were insignificant. At both the sowing dates, highest germination percentage was recorded for large seeds (32.86-46.67 %) followed by medium (31.43-33.33 %) and lowest germination (6.67-7.14 %) was recorded for small size seeds. In all parameters assessed, sowing time $S_2$ had the best performance in combination with large seed size. Thus, September is suitable month for best germination, growth and seedling vigour and large seed size is recommended to silviculturists and tree planters. The information on seed germination and seedling growth is vital both for conservation and rehabilitation of degraded lands.