• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.97-102
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• 2000

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.330-338
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• 1999

Extensive research has been conducted on effects of drought stress on growth and development of soybean but information is rather restricted on the limited-irrigation system by way of precaution against a long-term drought condition in the future. The experiment for limited-irrigation was conducted in transparent vinyl shelter at Asian Vegetable Research and Development Center (AVRDC), Taiwan in 1997. Two soybean varieties, Hwangkeum and AGS292, improved in Korea and AVRDC, respectively were used for this experiment. The relationships between normalized transpiration rate (NTR) and fraction of transpirable soil water (FTSW) in both varieties were similar that the NTR was unchanged until FTSW dropped to about 0.5 or 0.6. At FTSW less than those values, NTR declined rapidly. Days required to harvest in both varieties were significantly prolonged at IR6 treatment compared to any other treatments. Daily mean transpiration rate was significantly higher at IR5 treatment, as averaged over varieties. Similarly, water use efficiency was also high at 1R5 treatment. In both varieties, seed yield was the greatest at the IR5 treatment, as compared to any other limited-irrigation treatments, due to the increased seed number and high transpirational water use efficiency. The indices of input water and seed yield for the different limited-irrigation treatments against control indicated that Hwangkeum produced 59.6% or 60.7% of seed yield using 36.1% or 44.9% of input water, as compared to control, by irrigation at only R5 or R6 stages, respectively. The AGS292 produced 56.1% of seed yield with 35.4% of input water of control, when irrigated at R5 stage. The results of this study have elucidated that the limited irrigation at R5 stage in soybean can be minimized yield loss with such small quantity of water under the environment of long-term drought stress and the expected shortage of agricultural water in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.105-112
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• 1998

Seeds of medicinal soybean [Glycine max(L.) Merill] are characterized by a black seed coat, white stripe at hilum border, yellow cotyledon, and very small seed weight. Production of this medicinal soybean has recently increased as a consumption increased. The objective of this study was to evaluate the growth characteristics and seed yield of collected medicinal soybeans and to obtain basic information on production practices and breeding materials. The collected medicinal soybean lines were cultivated at three locations for two years. Twenty-seven lines were planted at the Research Farm, Korea University, Namyangju city, on May 23, and at the Research Farm, Kyungpook National University, Taegu, on May 20, 1995. In 1996 field experiments, forty-four lines were planted on May 25, at Research Farm, Korea University, and twenty-seven lines among those were planted on June 7 at the Research Farm of National Yeongnam Agricultural Experiment Station, Milyang city. The investigated lines had purple or white flower. Flowering and maturing dates were similar or later than those of the control cultivars. Branch number was greater for the investigated lines. One hundred-seed weight of the lines ranged from 8.5 to 15.0 g. Mean seed yields ranged from 1.54 to 2.89 MT/ha. Nine lines of the investigated medicinal soybeans showed higher yield capacity than the control cultivars. Further research should be done on the improvement of the production system and breeding program of medicinal soybeans.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.2
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• pp.101-106
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• 2003

This experiment was carried out to investigate the growth characteristics and seed productivities of orchardgrass "Hwabsung 2 ho" according to seeding times in the NLRI from 2001 to 2002. The experimental design was a randomized block arrangement with three replications. Seed was sown on 10th, 20th, and 30th of Aug. and 10th, 20th, and 30th of Sept. in 2000 and 2001, respectively. Establishment of seedling was worse in seeding of Aug. 10th because of rainfall. Number of panicles per $1\textrm{m}^2$ was numerous in seeding of Aug. 20th and was fewer according as seeding time was later. But panicle did not nearly appear in seeding after Sept. 20th. Seeding of Aug. 20th produced seed yield of 759kg/ha and have most seed yield components. But according as seeding times were later than Aug. 20th, the seed yield was linearly decreased with seed yield components worse.nts worse.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.539-547
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• 1997

This study was carried out to identify how soybean seed protein concentration is influenced by climatic factors. Twelve lines selected for seed protein concentration were studied in 13 environments of North Carolina. Sensitivity of seed protein concentration, total seed protein, and seed yield to climatic variables was investigated using a linear regression model. Best response models were determined using two stepwise selection methods, Maximum R-square and Stepwise Selection. There were wide climatic effects in seed protein concentration, total protein and seed yield. The highest protein concentration environment was characterized by the most high temperature days(HTD) and the smallest variance of average daily temperature range (VADTRg), while the lowest protein concentration environment was distinguished by the fewest HTD and the largest VADTRg. For protein concentration, all lines responded positively to average maximum daily temperature(MxDT), HTD, and average daily temperature range(ADTRg) and negatively to ADRa, while they responded positively or negatively to average daily temperature(ADT), variance of average minimum daily temperature (VMnDT), and VADTRg, indicating that genotypes may greatly differ in degrees of sensitivity to each climatic variable. Eleven lines seemed to have best response models with 2 or 3 variables. Exceptionally, NC106 did not show a significant sensitivity to any climatic variable and thus did not have a best response model. This indicates that it may be considered phenotypically more stable. For total seed protein and seed yield, all the lines responded negatively to both ADTRg and VADRa, suggesting that synthesis of seed components may increase with less daily temperature range and less variation in daily rainfall.

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.229-235
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• 2014

Flax (Linum usitatissimum L.) has been used for the edible oil in Korea. The evaluate the effect of plant growth retardants on flaxseed yield, oil content, and gibberellin level, chloromequat chloride (CMC), paclobutrazol (PBZ), and prohexadione-Ca (PHC) were used as plant growth retardants in this study. These plant growth retardants were foliar-sprayed to flax plant at 55 days after seeding. The concentrations of each plant growth retardant were as followed: CMC 250, 500, 1000 ppm, PBZ 40, 80, 160 ppm and PHC 500, 1000, 2000 ppm. PHC treatment to forming bolls was more stimulated than CMC and PBZ. The highest ripened seed rate was observed in PHC treatment at 2000ppm. The high see yields were obtained in PHC treatment following PBZ and CMC, in turn. Seed yield that significantly increased in PBZ and PHC was found to be increased 12.4 ~ 23.9% as compared to the control. The PHC showed higher flaxseed production and oil yield than that of CMC and PBZ. The results obtained in the present study suggest that higher concentration of plant growth retardant (PHC) increased flaxseed yield and oil content. The optimal concentration of PHC treatment was observed in 2000 ppm. It concludes that the foliar application of PHC 2000 ppm may be useful for the increasing oil and higher seed production in flax plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.73-80
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• 2006

Sesame (Sesamum indicum L.) seeds contain abundant oil and antioxidative lignans related to the seed quality. To evaluate the potential effects of drought stress on the chemical composition of sesame seeds, eighteen cultivars were imposed water-deficit condition by withholding irrigation during 15 days at podding and maturing stage, compared with well-watered plants as control in seed yield and chemical composition. Drought treatments showed great decrease of seed yield with not affecting seed weight. The contents of sesamin and sesamolin decreased while lignan glycosides inversely increased in response to drought stress. Oil content was not significantly changed by drought treatment in spite of its slight decrease. In case of fatty acid composition, there were significant differences in increase of oleic acid while inverse decrease of linoleic acid under drought stress condition. These results demonstrate that the chemical composition of sesame seed may be modified with drought stress. In particular, the increase of sesaminol glucosides with strong antioxidative activity was observed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.269-273
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• 2006

Multiple linear regression analysis was conducted to interpretate the relationship between sesame grain yield and its components under early sowing cropping condition. The t test showed that stem length, number of capsules per plant, 1000 seeds weight and seed weight per plant gave significant contribution to sesame grain yield, therefore those variables were assumed to mostly influenced components to grain yield of sesame. In the stepwise regression analysis, the predicted equation for sesame grain yield per square meter (Y) was Y = -7.900 + 0.150X1 + 0.461X5 + 15.553X6 + 8.543X7. Meanwhile, F value showed that stem length, number of capsules per plant and seed weight per plant gave significant contribution to sesame grain yield, while 1000 seeds weight did not significantly show. Based on the results, it is reasonable to assume that high yield. potential of sesame under early sowing cropping condition would be obtained by selecting breeding lines with long stem length, number of capsules per plant, and seed weight per plant, which was different result at the late sowing cropping condition in which days to flowering and maturity were assumed to be more affected factors to the sesame grain yield.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.269-276
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• 2019

A semi-greenhouse experiment with field grown soybean (Glycine max L. cv Deawon, Uram, Jinpong, Soyon, Pungsangnamul, and Haewon) was performed in 2018. The experiment was aimed to investigate individual impacts of drought stress on soybean characteristic and seed yield. The three treatments were used in non-water stress (Control) during the soybean growth season, vegetative stage stress (VS), and flowering period stress (FS). Leaf number, LAI, leaf nitrogen concentration, and leaf biomass were decreased by drought at R4. In our study, the number of pods was 33.6% and 40.5% lower, respectively, in control than in VS and FS. In 100 seed weight, was 16.1% and 10.1% lower, respectively, in control than in VS and FS at R8. As a result, seed yield was 39.8% and 45.1% lower, respectively, in control than in VS and FS. Depending on the drought period, Daewon and Haewon showed a large decrease in yield, while Soyon did not change. The results of this study showed that flower and beginning pod setting stage responded more sensitively to the drought period than vegetative stage. Overall, these results demonstrate soybean seed yield formation more sensitive the during the flowing and beginning pod setting stage. We conclude that adequate water supply for pod setting stage, guaranteeing a high seed yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.363-370
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• 1997

This experiment was carried out to investigate the effect of the mixed rates of endophyte-he and -infected seed on the endophyte fkquency, dry matter yield and forage quality of tall fescue(Festuca arundinacea Schreb.) at the Experimental Field of Grassland and Forage Crops Division, National Livestock Research Institute, Suweon, from 1993 to 1994. The results obtained are summarized as follows: Endophyte frequency was increased with mixed rates of higher endophyte-infected seed, however, it was not different between mixed rates of endophyte-free and -infected seed. DM yield of tall fescue was not different between mixed rates of endophyte-fke and -infected seed, and CP, NDF, ADF and IVDMD contents of forage quality were not influenced by mixed rates of endophyte-he and -infected seed. However, the weed contents were slightly increased with high level of endophyte-free seed. The results demonstrated that endophyk-fke tall fescue did not seem to be greatly weak under poor conditions, if the weed contents were slightly increase.