• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.299-306
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• 2005

Soybean seed injury was analyzed in the experiments that soybean pods were allowed to be sucked by adults of the bean bug, R. clavatus, and were picked with a specimen pin. While attack by the bean bug at podding stage of soybean caused the increase of empty pods and completely-undeveloped seeds, attack at full seed stage caused the increase of seeds wi distinct injury mark on seed-coat. The ratio of deformed seed was lower than those of injury-marked seed and undeveloped seed when attacked during all stages. In at full bloom stage hardly produced injury-marked seeds and deformed seeds. When the injured seeds were dyed with acid-fuchsine solution, stylet sheaths of R. clavatus formed on seed-coat were observed in 83% of undeveloped seeds formed under attack during podding stage and in 91% of injury-marked seeds formed during full seed stage. In pods injured with a specimen pin at full seed and full maturity stages, no healthy seeds could be obtained from the pods. And the more picked at full seed stage, the more deformed seeds were produced and the higher weight reduction of injury-marked seed occurred. However, pin-injury at full maturity stage didn't give rise to weight reduction of seeds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.310-317
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• 2006

This study was conducted to investigate the influence of drought stress during the pod developing and seed filling stage on source-sink relationships of soybean (Glycine max). Drought treatments were imposed by withholding water at the full-pod stage, 19 days after flowering, and then limited watering was relieved at 15 days after the initiation of drought treatment. Soybean seed yield was reduced by 39% mainly due to decreased pod number under drought stress, but the 100-seed weight was relatively less reduced. In spite of the 15-day drought during the full-pod stage, soybean produced good seeds showing similar l00-seed weight, protein, starch and soluble sugar content to those from the well-watered. Although drought during the full-pod stage caused source limitations; i.e. accelerated leaf senescence and reduced leaf soluble sugars, it did not cause limitations of other source characteristics such as SGR and leaf starch level. This is because the reduction in size of sinks, such as pod and seed abortions compensated for source limitations, resulting in balanced source-sink as expressed by LAR and the ratio of leaf area to seed dry weight. Drought stress during the pod developing and seed filling stage did not disrupt the source-sink balance

• Korean journal of applied entomology
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• v.49 no.4
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• pp.357-362
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• 2010

Soybean seed injury was analyzed in the experiments in which the bean bug, Riptortus pedestris(Hemiptera: Alydidae), was released into screen-caged pots containing full seed stage(R6) of soybean. When the different stages of insects, from the 3rd instar nymphs to adults, were released into pots during 8 days in soybean R6 stage, soybean seeds with injury marks (B-type seeds) increased. The weight reduction ratio in B-type seeds was highest in the injury by the 5th instar nymphs, while the daily-produced number ratio of B-type seeds was small in the treatment. In the injury by the different number of adult released into pots, 4, 8, 16 adults caused a significant increase of B-type seeds, while 16 adults caused the significant increase of the deformed (C-type) seeds. In the injury by the different release period of adults, the total number of pods was not significantly different among treatments, while the total seed number harvested was significantly small in the release for 48 days. The release for 8 and 16 days caused a significant increase of B-type seeds, while the release for 48 days caused the increase of C-type seeds. The results indicated that injury of soybean R6 stage by the bean bug produced soybean seeds with distinct injury marks at relatively low density and during short term attack period, while it produced deformed seeds at high density and during long attack period.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.165.2-165
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• 1997

No Abstract, See Full Text

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.221-224
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• 1999

A field experiment was carried out to observe the weed control effects of vetch and to evaluate vetch characteristics on clay loam soil in no-till direct-sown rice-vetch cropping systems. The effects of weed control, forage productivity, and N content of vetch plants were investigated. With the progress of plant growth, density of Chinese milk vetch (Astragalus sinicus L.) gradually decreased, but densities of foxtail and other weeds decreased steeply due to the depression by the over-shaded vetch canopy in a no-till direct-sown rice-vetch cropping paddy field. The vetch density in tillage systems was lower than in notillage cropping systems. Lower vetch density occurred with an increase in foxtail density and other weeds. Weed control effect increased by the progress of vetch growth, which indicated that the vetch canopy over-shaded the weeds. Vetch straw was degraded rapidly submergence after with water at the time of wet sowing of rice. Early harvesting of vetch seed resulted in lower seed germination. To acquire enough seedlings without re-sowing, the harvesting of seed should be delayed at least 28 days after the flowering stage in order to ensure the vetch population is sustainable in a no-till direct-sown rice-vetch cropping system. In order to improve the survival of vetch plants, vetch seeds should germinate from the heading .stage to before the full-ripening stage of rice plants. To enhance the percent of over-wintering survival, vetch seeds should germinate no later than the end of October in southern Korea. The dry weight of vetch plants increased with the progress of vetch growth until the flowering stage but N content decreased for 30 days from before the flowering stage (2.9%) until the ripening stage (1.8%). We concluded that Chinese milk vetch could have an effect on weed control before the flowering stage, sustainability without re-sowing of seed annually, and effective green manure for rice pre-crop in no-till direct-sown rice-vetch relay cropping systems.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.85-93
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• 1984

This research was carried out to study the seed dormancy of radishes which were used for summer vegetation. The differences of dormancy of cultivars, maternal effects, the effect of full day length to mother plants, and the effects of chemical treatments for breaking the seed dormancy were considered for this study. These results sere summarized as follows; 1. The germination percentage of 7 cultlvars sown just after harvest were as follows;SP70-:0, PS11-:37.5, GJ75-:75.5, JD127-:77.5, YH85-:81.0, M55-:96.5, and JC73-:98.0%. 2. The dormany of $F_1$ seed of radish was severe when SP70-was used for mother plant. 3. Germination behavior was different by the maturity of plants grown for seed production. The dormancy of seed harvested from immature field-grown plants sown Nov. 10 was deeper than mature plants sown Mar. 22. 4. The germination ratio of tire seed of SP70-radish was increased by treatment of full day length to tire mother plant during full period of growing or since first flowering stage, while that was 0% by treatment since yellow ripening stage. 5. GA 200 ppm+thiourea 0.2% treatment was most effective for breaking of radish seed dormancy.

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.167.2-167
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• 1999

No Abstract, See Full Text

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.5-10
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• 2005

This experiment was conducted to clarify the functions of supernodulating characters on seed yield determination through the comparison of agricultural traits of supernodulating soybean mutants, Sakukei4, SS2-2, and their parent cultivars, Enrei and Shinpaldalkong2. The plant dry weights of supernodulating mutants, Sakukei4 and SS2-2, were $52\%$ and $61\%$ of their wild type parents at full seed stage (R6). However, the relative growth rate (RGR) from the pod set stage (R3) to R6 of Sakukei4 was 0.022 g/g/day and that of SS2-2 was 0.016 g/g/day, which were higher than those of their parents. Nodule number and dry weight were increased in two supernodulating mutants by the R6 stage. The nitrogen concentrations of leaf, petiole and stem of Sakukei4 were higher than those of Enrei. SS2-2 showed higher nitrogen concentration in petiole than Shinpaldalkong2 had. The positive correlations were appeared between nodule dry weight, plant dry weight and pod number, in two supernodulating mutants during the period from R3 to R6 stage. Although all of the yield components and seed yield were lower in two supernodulating mutants than their parents at the stage of full maturity (R8), the harvest index was higher in supernodulating mutants. The increasing rates of pod number to stem dry weight in two supernodulating mutants showed the higher than those of two their parents at R8 stage. In conclusion, the relative growth rates during the early to the middle reproductive growth period were higher in supernodulating mutants than the wild types. This could be resulted in an increase in pod number. The increase of relative growth rate was the result of the successive supplement of nitrogen source from biological nitrogen fixation (BNF) of nodules during the middle reproductive growth period in supernodulating mutants.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.106-110
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• 1985

This trial was carried out to find out the optimum ridge and seeding rate for the seed production of Festuca arundinacea S. (variety Alta). It was composed of three ridge level (12, 18 and 24cm) and four seeding rates (10, 15, 20 and 25kg/ha) in a split-plot design with 4 replications. The experiment lasted from September 1979 to October 1981. 1. The beginning of heading state was May 12 and the date of full flowering stage was June 2. The optimum stage for the seed harvesting of Festuca arundinacea was about 43 days after beginning of heading stage. 2. The number of panicles were 157 per square meter from the best treatment 18cm ridge with 15kg seed/ha. And the 1000 grain weight was 2.79g for the treatment 12cm ridge with 10kg seed/ha. 3. The average seed yield for two years was 681kg/ha and the largest 831kg/ha for the treatment 18cm ridge with 25kg seed/ha. 4. the average germination rate of the harvested seed was 90.7 percent, and it showed a little higher germination rate from the lower level of seeding rate. 5. The average total DM production with two cuttings of aftermath was about 6715kg/ha. According to the increasing seeding rate and narrowing the ridge, DM yield was higher.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.220-220
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• 2017

Soybean (Glycine max (L.) Merill) is a very outstanding material crop with high protein and oil contents. We conducted this study to evaluate forage value and usability of soybean varieties as livestock forage. Three soybeans cultivars, OT93-26, Geomjeongsaeol, and Pungwon, were evaluated for forage use in this study, and Kwangpyeongok and Yeongwoo were used as check forage corn and rice, respectively. The whole soybean plants were harvested at the R5 (beginning seed development)- and R6 (full seed)-reproductive stages for analyzing forage usability and quality. Days to harvesting of the R5 stage-OT93-26 was the shortest among the tested crops while that of Yeongwoo was 122 days. The fresh and dry matter yields of all 3 soybeans were greater at R6 stage than at R5. Crude protein of the soybean cultivars harvested had a higher compared to the rice and corn regardless of the harvesting stage. Contents of crude fiber, neutral detergent fiber and acid detergent fiber of Yeongwoo had the lowest whereas Pungwon harvested at R5 were the highest. Among the soybeans, digestible dry matter, dry matter intake, and relative feed value of R6-harvested Geomjeongsaeol and Pungwon were high more compared to those at the R5-harvested, but in case of OT93-26 those at R6 stage were inversely measured rather than those at R5 stage. In conclusion, soybean can be used as s forage with high nutritive value for livestock. Moreover, Geomjeongsaeol can be applied to develop new forage soybean varieties with high nutritive value, and R6 stage is the optimum harvesting stage in yield and quality of the tested soybeans more than R5.