• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.226-235
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• 2002

This experiment was to evaluate lodging characteristics of 35 recommended rice varieties of Kyonggi-do at normal (110 kg N/ha) and hen (220 kg N/ha) nitrogen application rates during 1999 to 2000. At heavy N fertilization rate, varieties that were highly resistant to lodging were Obongbyeo, Daejinbyeo, Naepoongbyeo, Nonganbyeo and Ilpumbyeo. Fourteen varieties including Daeanbyeo were moderately resistant and 11 varieties including Jinbubyeo were susceptible to lodging. The lodging-related characters which showed the highest effect on lodging at lodging degree of 9 were culm length and height of center gravity, culm length at lodging degree of 5, and culm length and the third internode length at lodging degree of 3 or below. The difference in rice yield between normal and heavy nitrogen fertilization rate was within 5% in early-maturing varieties but there was great yield difference in mid- and late-maturing varieties depending on the degree of lodging. Consequently, stable rice yield could be obtained by selecting lodging-resistant varieties and lowering fertilization rate, specially in the paddy field where lodging occurrence is common.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.5-9
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• 1987

In order to investigate the occurrence status of tiller at the upper node of rice, this trial was conducted with different eco-typed and 23 cultivars in 1983 and testified the effect of fertilizer levels with Indica x Japonica cultivars in 1984. In occurring of tiller at the upper nodes, upper 2nd, 3rd node and lower 2nd, 3rd node rose simultaneously. The tillering rates of the upper nodes of Japonica x Indica cultivars were more than Japonica cultivars and early maturing cultivars were more than medium or late maturing cultivars, respectively. Highly negative correlations were found between the tillering rate of upper nodes and days from transplant-ing to heading and bending angle degree of 2nd node. The tilleriiig rate of the upper nodes treated with different levels of fertilizer increased with non-fertilizer than those of standard (N-P-K =15-11-13kg/10a) or heavy (N-P-K =25-15-18kg/10a) levels.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.354-354
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• 2017

Rice grain yield is determined by crop dry matter production that is sensitive to temperature. Our objective was to determine whether the difference in temperature between years had an impact on the relationship between yield components and grain yield. Field experiments were conducted under machine transplanting cultivation by using yield data of two japonica rice varieties, Odaebyeo (early maturing) and Nampyeong (mid-late maturing), in 2013 to 2016 in Suwon, Korea. Plant height, dry weight, and yield components were examined by analysis of variance, correlation. The milled rice yield of the two varieties were the highest in 2016, however the lowest yields were observed in the different years. In 2016, Odaebyeo produced $0.96t\;ha^{-1}$ greater milled rice yield than in 2015, and Nampyeong produced $1.11t\;ha^{-1}$ greater yield than in 2013. The correlation analysis indicated that spikelet per panicle (R = 0.53) was associated with grain yield of Odaebyeo. In Nampyeong, biomass at heading date (R = 0.74), 1000-grain weight (R = 0.71), spikelet per panicle (R = 0.58), and panicle number per $m^2$ were associated with grain yield. Sink size (spikelet number per $m^2$) of the two varieties responded to accumulative temperature from transplanting to panicle initiation stage. In this experiment, optimal accumulative temperature before panicle initiation has effect on increased spikelet number and/or number of panicle that were mainly responsible for yield difference. Rice production research to increase grain yield should consider all yield components, but increased emphasis on biomass production before heading is also necessary as well as grain ripening conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.255-262
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• 1997

To estimate the total dry matter(TDM) of rice plant by non-destructive method, spectral reflectance from rice plant canopy was measured by using the spectroradiometer (LI-1800, LICOR Inc.) with one week interval during the rice growing season at Suwon paddy field in 1993. Two medium late maturing rices, Daechung-byeo Ilpum-byeo, and one early maturing variety, Jinbu-byeo, were cultured to observe TDM, then they were compared with those estimated by vegetation index together. Vegetation index determined by the reflectance of visible against near infrared wavelength showed high correlation with TDM. Vegetation index derived from narrow band(10nm interval) ratio, R910/R460, has the highest correlation coefficient with TDM. TDM estimated from R910/R460 from transplanting to heading stage corresponded well to measured values (Y=21.2428X-212.734 ; $R^2$=0.87). But another vegetation index, NIR(720~1,100nm) /Red(600~700nm) showed higher correlation with TDM than NIR(720~1,100nm) /Blue(400~500nm) did from heading stage to maturity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.65-69
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• 1973

This experiment was carried out to determine the adequate amount of nitrogen for densely and lately seeded soybean, and the results obtained are as follows, 1) Various fertilization amounts of nitrogen did not effect the date of emergency, but the flowering and the maturing dates were delayed at the plots fertilized the nitrogen heavily. 2) In accordance with an increasing amount of nitrogen fertilization, the length of the stem and the internode was significantly elongated but the stem diameter was thinned down, and the latter was suggested to be the cause of lodging. 3) The 1, 000 grain weight and the number of pods per hill were decreased according to the increasing the amount of nitrogen fertilization. 4) A highly significant difference in grain yield was recognized between varieties but among treatments. However, in case of the extremly late cultivation, the grain yield of the early maturing variety (Choongbukbaeg) was increased at the plot of 6 kg nitrogen.

• Korean journal of applied entomology
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• v.20 no.3 s.48
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• pp.131-134
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• 1981

Native soybean collections were evaluated to search a resistant gene source to purple blotch caused by Cercospora kikuchii. Among 467 native lines, about $28.9\%$ of the lines was less than $0.1\%$ and $13.4\%$ was over $2\%$ in natural infection of purple blotch. Natural infection seemed to be significantly associated with weather conditions at the early podding stage. A significant correlation between natural infection and purple discoloration by seed inoculation was observed and this method seemed to be effective as a preliminary screening technique for resistance to purple blotch. Most of the late maturing native soybeans showed susceptible reaction by the seed inoculation contrary to low infection under natural conditions, indicating that the low natural infection might be due to disease escaping by the late maturing instead of their genetic resistance.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.216-221
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• 1982

This experiment was conducted in Jeonnam to investigate the effects of fertilizer amounts at two application levels on disease severity of bacterial leaf blight, yield and qualify of rice grains using nineteen rice cultivars. Incidence of bacterial leaf blight was more severe in the field with higher amount of fertilizer application. Disease severity was also different depending upon maturity of rice cultivars of early maturing group, however, the flag, second and third leaves were diseased in rice cultivars of medium late maturing group. Such differences were more obvious in the field with higher amount of fertilizer application than in the field with ordinary fertilizer application. Rice cultivars such as Taebaegbyeo, Hangangchalbyeo, Baegunchalbyeo, Palgwangbyeo and Milyang 42 were resistant whereas rice cultivars such as Milyang 30, Geumgangbyeo, Nagdongbyeo and Jinjubyeo were susceptible to bacterial leaf blight in both treatments. However, fertilization rate and percentage of ripeness were decreased resulting in heavy loss of yield. The rate of green-kerneled rice was increased resulting in poor qualify.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.302-307
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• 1996

Seed coat anthocyanin can be purified by soaking 3 times in methanol solution supplemented with one percent of HCl. Anthocyanin content was very wide range in collected lines and average anthocyanin content of black seed coat lines was 15.07 permillage, but that of white mottled on brown seed coat lines was 0.31 permillage. In black seed coat lines green seed embryo type has more anthocyanin in amount compare to yellow seed embryo. Anthocyanin accumulation was promoted in late maturing lines compare to early maturing lines. Positive correlations were observed among 100 seed weight, days to flowering, days to growing and anthocyanin content, but negative correlation between days from flowering to maturity and anthocyanin content. Collected black seed coat lines were divided into two maturity groups. Group VI which has longer than group V in days to maturity accumulated more anthocyanin compare to group V. When the seeding date was May 15, highest anthocyanin content was observed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.313-326
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• 2023

Owing to adverse weather conditions, there is a heightened focus on actively researching the regulation of the sowing date in field crop cultivation. Soybean, a prominent field crop with extensive acreage and production, is a photophilic and thermophilic crop characterized by short-day photoperiodism. Identifying the optimal sowing time is crucial for mitigating the effects of severe weather conditions on soybean yield. Precise control over the timing of soybean sowing is the key to minimizing yield reduction due to unfavorable weather conditions. Temperature, photoperiod, and their interplay are the most significant factors influencing soybean cultivation among various weather factors. We conducted an experiment using three Korean soybean cultivars with varied maturities (Hwangkeumol: early maturing and Daewonkong and Pungsannamulkong: late maturing) in 2013 and 2014. Our investigation covered aspects of soybean growth, development, yield components, isoflavones, and visual seed quality. Across all three varieties, isoflavone levels increased with later sowing dates, while other measured components exhibited significant variations based on the sowing date. This study also provides valuable insights for the selection of suitable cultivars that perform well in soybean cultivation at various durations of maturity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.17-19
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• 2003

The purpose of this study was to evaluate the effect of pesticides on insect pest control of Rhophalosiphum nymphaeae, growth characteristies and dry root yield from the cultivated after early maturing rice cropping. All pesticides treated had no effect on the growh period, flowering rate of Alisma plantago. The major pesticides were methomyl-Lf, 24.1 %, imidacloprid-Wp, 10%, carbosulfan-Wp, 20%, and methomyl-Wp, 45%. Dry yield of root were increased largely with imidacloprid-Wp, 10% (10g/20$\ell$), pesticide than the other pesticides and control. All pesticides were had no injury with recommended concentration. On the other hand all pesticides were slightly harmful in the double dosage level for the Alisma plantago.