• Korean Journal of Organic Agriculture
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• v.11 no.3
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• pp.75-90
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• 2003

A total of 192 Korean landraces were investigated for the comparison of each other as useful germplasm to organic farming and examined correlation between quantitative traits. Almost Korean landraces were classified into medium-heading variety and average days from seeding to heading was 111.1 days. Plant height and culm length were longer about 20∼40cm than general Japonica cultivar. Average width of leaf blade and average length of panicle were 1.3cm and 22.4cm, respectively, Average number of panicles per plant was 10.0 and almost varieties showed low tilling habit. Average length/width ratio of brown rice was 1.7 and several varieties were long grain type and average 1,000 grain weight was 21.6g. In correlation coefficient among quantitative traits, positive significant correlations were observed between culm length and leaf width, days from seeding to heading, but negative correlations were observed between days from seeding to heading and 1000 grain weight. 27.1% of Korean landraces showed weak and lodging degree in culm strength and 3.6% of total varieties showed purple margin on leaf blade and leaf sheath. In leaf blade angle and flag leaf angle, erect type was 46.9% and 10.9%, respectively. 24.0% of total varieties showed the slow and late degree of leaf senescence. The rate of awned type, waxy type and brown seed coat were 74.5%, 20.3% and 4.2%, respectively. The color of stigma, spikelet, apiculus and awn showed diverse color such as white, brown, red and purple.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.721-726
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• 2006

Mosquitoes are carriers of malaria and encephalitis. This study performed for eco-friendly control of mosquitos by using genus Acorus. Several solvents were used for the extraction of genus Acorus; water, ethanol, and methanol. Grinded leaves and roots were also included. Acorus extracts killed mosquito larvae and the ethanol extract showed the best result. Autoclaved Acorus water needed long time to kill mosquito larvae. $LT_{50}$ of 1 % Acorus calamus decoction was 13.6 hrs and 1 % autoclaved Acorus water was 53.6 hrs. $LT_{50}$ of 0.05% Acorus calamus rhizome powder was 28.5 hrs. $LT_{50}$ of 0.5% Acorus calamus leaf powder was 10.8 hrs. $LT_{50}$ of 0.1 % Acorus calamus decoction was 63.4 hrs and 0.1 % Acorus calamus ethanol extracts was 48.6 hrs and 0.1% Acorus calamus methanol extracts was 53.9 hrs. $LT_{50}$ of 0.4% Acorus gramineus decoction was 45.5 hrs, 0.4% ethanol extracts was 10.9 hrs, 0.4% methanol extracts was 10.2 hrs. $LT_{50}$ of ethanol extracts was shorter than other extracts. Acorus calamus rhizome powder could be used for the eco-friendly control of the mosquito larvae.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.257-263
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• 1992

Immature embryos were tested for investigating the effect of cold treatment duration and GA$_3$ concentration on the vernalization response in barley. Immature embryos were cultured on B$_{5}$ medium with GA$_3$ for 5 days, and were transplanted under 20/15$^{\circ}C$ temperature after cold treatment. Germination rate and shoot length were increased more in 20-day-old embryos than those in 13-day-old ones but germination day was decreased. Addition of 1 or 10 ppm of GA$_3$ to B5 medium was effective on the growth of immature embryos. The higher GA$_3$ concentration was, the shorter time from embryo culture to flag leaf emergence and heading was. The earlist flag leaf emergence and heading were showed on treatment of 1 or 10 ppm of GA$_3$, but GA$_3$ did not completely replace vernalization. The days to flag leaf emergence of immature embryo-cultured barley with cold treatment for two and three weeks was shortened by 3 and 18 days at 1 ppm GA$_3$, and 16 and 20 days at 10 ppm GA$_3$, respectively, when compared to 0 ppm GA$_3$ culture with cold treatment for three weeks. It was at 10 ppm GA$_3$ with 3 weeks cold treatment that showed the lowest culm length, spike length and number of grain per spike. GA$_3$ concentration was not correlated significantly with each character in 1 week cold treatment, but was significant with each character in 2 weeks. In 3 weeks cold treatment, it was except for days to heading. Correlation between cold treatment duration and culm length was negative in 0 ppm GA$_3$. In 1 or 10 ppm of GA$_3$, all characters had highly negative correlation with cold treatment duration.n.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.156-160
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• 2020

This study was conducted at the National Institute of Animal Science from 2010 to 2017. As a variety that is sufficiently productive in the southern regions to replace imported varieties and sufficiently cold-resistant to be cultivated in the central-northern regions, "IR605" was developed and submitted to the Korea Seed & Variety Service in an application for protection. The novel Italian ryegrass variety "IR605" is a diploid with green leaves, a semi-erect growth habit before wintering, and an erect growth habit in the spring. "IR605" was a medium maturing variety with a heading date of around May 15th. "IR605" had a flag leaf width of 9.9 mm, flag leaf length of 26.7 cm, and plant length on the heading date of 100 cm, which was approximately 5 cm longer than "Kowinearly." The stem thickness and ear length of "IR605" are 0.08 mm thicker and 0.5 cm longer than those of "Kowinearly", respectively. The cold-resistance of "IR605" was weaker than that of "Kowinearly", but strong enough to be cultivated in Pyeongchang, Gangwon province. The dry matter yield of "IR605" (9,308 kg/hectare) was 20% higher than that of "Kowinearly", which was further pronounced in the southern region of Haenam, where there was a 52% increased (p < 0.05). The in vitro dry matter digestibility of "IR605" was 68.4% at which was slightly higher than that of "Kowinearly", The total digestible nutrients was 58.5%, which was slightly lower than "Kowinearly". Overall, the feed quality characteristics of "IR605" were similar to those of "Kowinearly".

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.113-118
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• 1974

A study was carried out to investigate the effect of application time of fertilizer nitrogen on its rate of uptake and its distribution in rice plant. The rate of applied fertilizer was 100kg/ha, as a single application at transplanting time and four equal split applications of 25kg/ha was applied at transplanting time, 3 weeks after transplanting, 1 week before the primodial initiation stage of growth and at the flag leaf stage of growth, respectively. The ammonium sulfate was labelled with N-15, as 1% atom excess for single application and 4.4% atom excess for split applications. The results are sumarized as follows: 1. The effect of split application of nitrogen on yield was observed. The yield of brown rice of the single application at transplanting time was 3.1 ton/ha and the split application was 3.4 ton/ha. However, without nitrogen the yield was reduced to 1.9 ton/ha. 2. The number of grains per panicle and 1000 grains weight were increased as split application of nitrogen, but for the number of panicles per hill and maturing rate, the single application of nitrogen revealed favorable results. 3. The rate of uptake of applied fertilizer nitrogen showed a tendency that the efficiency of fertilizer nitrogen increased by top dressing. The rate of uptake of applied nitrogen as basal application, first top dressing, second top dressing and third top dressing was 28%, 33% 51% and 63%, respectively. 4. After shooting stage of the growth, nitrogen in straws transfered to grains. The nitrogen applied at flag leaf stage was absorbed by root and easily accumulated in grains rather than straw.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.1
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• pp.10-14
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• 2013

This experiment was carried out to breed an early maturing variety of Italian ryegrass (Lolium multiflorum Lam.) in the Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan from 2009 to 2011. A new variety, 'Green farm II' is a diploid with green leaves and has a semi-erect growth habit in late autumn and erect growth habit in early spring, respectively. 'Green farm II' was on the $28^{th}$ of April in the heading date as an early-maturing variety. 'Green farm II' was also wider by 0.6 mm in flag leaf width, shorter by 1 cm in flag leaf length and shorter by 1 cm in plant length than those of the control variety, 'Florida 80', respectively. 'Green farm II' was thicker by 0.7 mm in stem thickness and strong in winter hardness. Dry matter (DM) yield (11,452 kg/ha) of 'Green farm II' was similar to that of 'Florida 80'. In vitro dry matter digestibility (IVDMD), total digestible nutrients (TDN), and relative feed value (RFV) of 'Green farm II' were 70.6%, 63.9%, and 114% higher than those of 'Florida 80', respectively. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) of 'Green farm II' were 31.7% and 52.6% which were 3.5% and 6.4% lower than those of 'Florida 80', respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.198-205
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• 1982

In 1980, rice was considerably damaged by abnormal low temperature. In this paper, to determine the effect of low temperature on the growth and nutrition of rice, the experiment were carried out: varietal response to low temperature in the region with different elevations. Regional differences of heading response to low temperature were observed among varieties. The difference of days between regions were bigger in tongil lines than Japonica lines. Especially, Milyang 42 and Hangangchalbeo might belong the cold suceptible group, since the varieties were severely delayed their heading in the high mountainous region as comparred to plain region. The delay of heading with low temperature was brought out grain sterility, and fertility and ripening ratio is influenced cold tolerance and elevations, and it's decreased yield. Varieties with higher grain sterility by low temperature have higher total nitrogen content, but tended to have lower potassium and phosphate contents in the flag leaf. High content of total nitrogen, low contents of potassium and silicate were observed in the sterilized grain chaff an the opposite result were noted in the ferilized grain chaff at the ripening stage. The results reveal that the balance of these mineral element may play an important role in ripening and possibly cold tolerance.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.228-228
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• 2017

Rice production and quality could be changed by temperature condition. Extremely high temperature event have been occurred more frequently for global warming. To increase rice quality against to global warming, breeding of heat tolerance rice cultivar is needed. Ilmi which is the one of Korean leading rice cultivar shows heat stress resistant character during ripening stage. Yield and quality (brown and milled rice) of Ilmi did not show significant different under high temperature condition compared to control condition. However, the main physiological characters for heat resistance of Ilmi have been not investigated yet. Therefore we try to investigate the heat tolerance characters of Ilmi. Two rice cultivars, Ilmi and Ilpum-which is heat susceptible rice cultivar, were cultivated under natural condition in wagnor pot until heading was appeared. After checking heading date, each material was cultivated under different temperature condition, heat($32/22^{\circ}C$) and control($26/16^{\circ}C$) condition. Anti-oxidant enzyme activity was checked during ripening stage in each material. Catalase and ascorbic peroxidase activity of leaf under heat stress condition were higher in Ilmi than Ilpum especially early ripening stage. Analyzing of stress resistance using $H_2O_2$, the flag leaf of Ilmi showed more green color than Ilpum with higher chlorophyll content than those of Ilpum. We also checked the amount of $H_2O_2$ content in young leaf of each material by treating high temperature. $H_2O_2$ content in each material was increased according to treatment time. However $H_2O_2$ content of young leaf in Ilmi was less than those in Ilpum. Also catalase and ascorbic peroxidase activity in leaf increased much faster in Ilmi than Ilpum. With those data, we confirmed that heat stress resistance of Ilmi is due to the higher anti-oxidant activity against to stress condition. We will investigate the heat tolerance characters of Ilmi more in further study to enhance the breeding effect of heat stress tolerance rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.130-136
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• 1982

Experiments were conducted to establish a measuring method of the stomatal aperture in the leaves of the wheat plant, and to find the diurnal movements of the stomate in leaves of different position and tillers. The measurement methods used were the infiltration and the microrelief impression methods. The aperture of the stomate in the infiltration method was expressed in terms of the solutions pent ration into the leaf and this was refered to as the infiltration score. A score I represents injection with 10% iso-butyl alcohol＋90% ethylene glycol solution and a score 7 represents injection with 70% iso-butyl alcohol +30% ethlene glycol solution. A linear relationship was obtained between the infiltration score and average pore width in a large number. of the stomata observed in the leaves of the adaxial and abaxial epidermis. The aperature of the stomate of flag and the 1st leaf were exhibited diurnal change with the maximum aperture at 10 A.M. but that of 2nd leaf reached maximum aperture 2 hours later than upper two leaves. After reaching the maximum aperture the stomata gradually closed and then completely closed at 6 P.M. The aperture of the stomate in the adaxial epidermis and the base part of the leaf were larger than those in the abaxial and top part of the leaf, and aperture of the stomate in the leaves of the main stem was larger than those on the tillers.