• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.49-53
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• 1998

Direct-seeding has major advantages such as labor and cost saving by eliminating preparation of seed bed and transplanting. But, it required increased input of fertilizers and pesticides because of the extended paddy period. Direct seeding in wet paddy (DSWP) gives faster growth and more uniform seedling emergence than direct-seeding in dry paddy. This research had an objective to develop an efficient N management practices for DSWP with split application of N fertilizer. A paddy field experiment was conducted to evaluate effects of starter N and N-topdressing which was delayed N application until 5-leaf stage, with comparison to transplanting (TP). Total amount of N application were two levels; 110kg and 77kg/ha. The N applications were split four times during rice growth stages; starter, topdressing at 5-leaf stage, top dressing at tillering stage, and topdressing at panicle initiation stage. DSWP had more tillers/$m^2$ than TP, but with the delayed heading. The DSWP plots which received N-topdressing at 5-leaf stage without starter N had higher leaf area index (LAI) and leaf greenness than the TP plot. Also, these DSWP plots had high leaf-N concentration at the heading stage, as calculated from leaf chlorophyll meter readings. Rice yield in DSWP with N-topdressing at 5-leaf stage was significantly higher than that in TP and in DSWP with starter N. Energy and N use efficiency were improved in DSWP with N-topdressing at 5-leaf stage. But, there were no significant differences in grain yield between the two levels of total amounts of N applications, 77kg and 110kg/ha. We concluded that starter N could not be used effectively by rice seedlings, but topdressing N at 5-leaf stage was an efficient N management for rice growth and yield in DSWP system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.189-194
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• 1988

To clarify the varietal differences of resistance to complete flooding, physiological characteristics in relation to flooding resistance in each growth stage of rice plants, the present study was carried out. The rate of survival after flooding at seeding stage of rice plants of the cultivar 'FR 13A' and Ind. X Jap. cultivars were 91.8% and 33.8% to 40%, respectively, while the Japonica varieties were completely dead. The tolerant varieties which has higher rate of survival showed the higher $O_2$ release, the higher catalase activity and lower peroxidase activity according to flooding treatment. Japonica type varieties showed the higher elongation of plant during flooding, lower recovery of flooding damage and the abrupt decrease of yield according to the increase of flooding periods in comparision to Ind. X Jap. crossed varieties when they were flooded at the active tillering stage. When rice plants were flooded at the booting stage, Ind. X Jap. crossed varieties had the higher photosynthesis, respiratory rate, root oxidizing power, ethylene evolution and lower yield reduction in comparision to japonica varieties.varieties.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.103-107
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• 1983

The effect of photochemical oxidants on rice plants was measured by growing the rice plants Nihonbare in pot in charcoal-manganese oxide filtered atmosphere and non-filtered air. Visible injury on the leaf blades of rice plants were observed in plants grown under the unfiltered air chamber, but plants under filtered air chamber were free from any injury. Fresh weight of stem and root at maximum tillering stage in unfiltered chamber were 16.8 and 46.4% less than filtered air chamber, respectively. Grain yield in unfiltered air chamber was also reduced by 14.7% compared to that of filtered air chamber. And the reduced yield paralleled increase in concentration of oxidants in the atmosphere at the experimental site. ABA content in rice plants cultivated in unfiltered air chamber was higher than in filtered air chamber, but the root activity of rice plants in unfiltered air chamber was remarkably decreased.

• Journal of Animal Environmental Science
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• v.19 no.1
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• pp.63-68
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• 2013

In vitro culture and radiation techniques were used for obtaining mutants tin tall fescue. Endophyte free and friendly tall fescue cultivars Kentucky-31 and Jesup were used for induction of genetic variability through in-vitro mutagenesis. Mature seeds was used for callus induction on 6 mg/L 2,4-D. Actively growing and compact callus was treated with three different doses of gamma rays (10 Gy, 30 Gy and 50 Gy). Maximum proliferation and plantlets regeneration growth was observed in control and minimum at 10 Gy. Furthermore, the maximum number of tiller in the irradiated population was observed in 10 Gy. The treatments 30 Gy and 50 Gy exhibited negative impact on the tillering potential of the tall fescue plant. The object of this study was to develop protocols for mutation breeding in tall fescue through radiation techniques.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.103-111
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• 1993

A greenhouse experiment was conducted to determine the number of optimum. tillers within a plant for high yield and to clarify the morpho-anatomical characteristics of cultivars having different tillering abilities. Optimum tillers, i.e tillers which produced heavy panicles were found to be around five to nine tillers per plant, although wider range may be possible if more cultivars were tested or under different growth conditions. Optimum tillers emerged within a short time after transplanting as compared with the other tillers. They exhibited longer tiller duration, produced more spikelets and had better filled spikelets, more vascular bundles and were taller with larger leaf area. However, the 1, 000 grain weight and fertility varied with cultivars and showed no general trend. Of this morpho-anatomical features, the total number of spike lets per plant was considered as the potential criterion for determining the optimum tiller number.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.35-40
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• 1982

New malting barley variety" Doosan #8" is a short culm, lodging registance, high tillering, good quality and high yielding variety. This variety was developed from the cross 'Tai Chung 2 rowed barley #1 \times Deba abed' made in 1972 at Sacheon Malting Barley Experiment station, Doo San Fann's Co. This variety was determined to recommend to the all malting barley production areas in southern part of Korea from 1981. of Korea from 1981.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.403-410
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• 2007

A field experiment was conducted to investigate effects of application time and rate of biofertilizer alone and in combination with chemical NPK fertilizer on growth, yield and quality of rice. The biofertilizer used composted food waste as substrate and added with effective microorganism. The treatments included recommended NPK fertilizer(RF, $11-5.5-4.8kg\;10a^{-1}$), half recommended NPK fertilizer(HRF, $5.5-2.8-2.4kg\;10a^{-1}$), half recommended NPK fertilizer plus $250kg\;10a^{-1}$ biofertilizer(HRF+Bio 250) and $500kg\;10a^{-1}$ biofertilizer(HRF+Bio 500). The biofertilizer treatments were applied at 0, 5 and 10 days before transplanting(DBT). Grain yield of HRF+Bio 250 at 5 DBT($648.4kg\;10a^{-1}$) was statistically similar to the highest obtained in the RF($654.1kg\;10a^{-1}$). Tiller numbers at HRF plus biofertilizer treatments were already high during the maximum tillering stage, and were similar with that of the RF and higher than that of the HRF during heading stage. Likewise, ripening ratio at HRF plus biofertilizer treatments was similar with that of the RF and higher than that of the HRF. Furthermore, all the biofertilizer treatments improved protein content but reduced the amylose content and palatability compared to treatments with chemical NPK fertilizer alone. Thus, HRF+Bio 250 at 5 DBT can be used to save 50% chemical NPK fertilizer and at the same time obtain an improved rice grain yield and quality.

• Journal of Life Science
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• v.20 no.1
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• pp.142-146
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• 2010

In order to find out better cultivation practices for environmentally-friendly agriculture, an experiment with four fertilizer levels and one cultivar, 'Boseokchal', and three lines, GG-05-03, GG-05-04, and GG-05-07 was carried out. Those lines had been selected from native green waxy rice over a period of five years (2004~2008). The tillering numbers of both the GG-05-03 and GG-05-04 lines were similar, but GG-05-07 was less than those. Regarding plant height, both GG-05-04 and GG-05-07 were higher than 'Boseokchal', while GG-05-03 was similar to it. There was no marked difference of quantitative character amond the three lines regarding grain weight and grain number of ear. 1000-grain weights of all three lines were slightly light compared to 'Boseokchal' cultivar. Head rice yields of both the GG-05-03 and GG-05-07 lines were less than 'Boseokchal', but the GG-05-04 line was similar to it. Only total lipids of all compositions of brown rice showed a slightly different rate compared to 'Boseokchal'. These results summarize that the GG-05-07 line was shown to be better than both the GG-05-03 and GG-05-04 lines for environmentally-friendly agriculture practices.

• Korean journal of applied entomology
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• v.27 no.2
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• pp.81-86
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• 1988

Experiments were conducted to investigate the locational and ovipositional preferences of the single and mixed populations of the brown planthopper(BPH), Nilaparvata lugens (Stal), and the whitebacked planthopper(WBPH),Sogatella furcifera (Hovath), with the different popula-tion densities at seeding, max-tillering, booting and heading stages of rice variety seonam by대. The WBPH showed a locational preference for the upper portion while the BPH was observed to stay generally on the lower portion regardless of rice growth stages, population density-levels and the single or the mixed populations of two species. At seeding, max-tillerinf, boo-tring and heading stage, the preference for the lower portion of the rice plants was found to be slighty reduced with the lapse of time, respectively, from the single or the mixed popula-tions of both the species. Ovipositional lication of both the species was found not to be affected by the different population densities at rice growth stage. Although the BPH prefered a ovi-positional location for the lower portion at seeding, booting and heading stages, its preference-was somewhat reduced with the developmental stages of rice plants, whereas the WBPH showed a ovipositional preference for lower portion at seeding stages, but prefered the same tendency of ovipositional preference for the upper and the lower portion, The location and ovipositional preferences were likely to be affected by the competition between species with the mixed populations rather than single.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.23-28
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• 2016

Zoysiagrass possessing the leaf yellowing with excessive tillers was first found in a golf course in Gyunggi province at last three to four years ago and since then have rapidly spread many golf courses in Korea. The symptom is very similar to that of yellow tuft or downy mildew, which is caused by Sclerophthora macrospora, on cool-season turfgrasses including Kentucky bluegrass and ryegrass. Microscopic study was firstly carried out to look over the presence of the pathogen in the infected leaf and stem tissues. Oospores and sporangia, reported as typical indicators of downy mildew, were obviously observed from the infected leaves. Using a set of primers based on the 18S ribosomal DNA from S. macrospora, the specific DNA fragment corresponding the gene was amplified. This study reveals that S. macrospora might be involved in spread of leaf yellowing of zoysiagrass with excessive tillers.