• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.1-17
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• 1977

Nitrogen responses to yield and other agronomic characters were studied using four rice varieties, Tongil, Jinheung, Milyang 23, and Yushin, at six nitrogen levels, 0, 10, 15, 20, 25 and 30kg/10a, in a silt loam soil at the Crop Experiment Station, Suweon, Korea, in 1976. Grain yields of Milyang 23 and Tongil were much higher than those of Jinheung and Yushin at high nitrogen levels (15-30kg/10a). Optimum nitrogen levels of the rice varieties, Tongil, Milyng 23, Yushin, and Jinheung, estimated by intersecting straight line, were 22, 19, 19, and 12kg/10a, respectively. Morpshological characters, dry matter production before and after heading, and yield components were dicussed in relation to the nitrogen responsivenees of the rice varieties. In addition, relationships between yield, yield components, and other agronomic characters were discussed to obtain some informations for higher rice yield.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.1-6
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• 1996

For reducing planting distance in greenhouse grown watermelon(Citrullus vulgaris S.) this experiment was carried out to study the effect of DIF on stem elongation and growth. Day temperatures ranged from $25^{\circ}C$ to 35$^{\circ}C$ : night temperatures ranged from $25^{\circ}C$ to 35$^{\circ}C$ at 5$^{\circ}C$ interval. Stem elongation, leaf size, dry weight and flowering were influence by day and night temperatures. Stem elongation and length of internode decrease with increasing night temperature at same day temperature. The optimums for number of leaves categories was with day at 35$^{\circ}C$, and flower production was the lowest at $25^{\circ}C$. Total leaf area meter was maximized at 35/30(DT/NT), but for size pet one leave was the largest 25/25(DT/NT). Responses of leaf size per leaves were similar to that of internode length, with maximum day and night at $25^{\circ}C$. Total plant dry weight was the highest 35/30 (DT/NT) and minimum occurring at 25/30(DT/NT). The shoot/root ratios of dry weight Increased with day temperature up to 3$0^{\circ}C$ and were the highest with night at $25^{\circ}C$. Chlorophyll contents decreased with decreasing day and night temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.125-136
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• 1981

This experiment was conducted to study the influence of different cultivation periods on some morphological and agronomic characteristics of rice plant at Iri, the Honam plain, in 1979. Early maturing varieties showed little delay in heading with late transplanting, but intermediate and late maturing varieties showed more than 7 day delay in heading. The number of days required to reach heading was over 55 and 67 days after transplanting in early and intermediate-late maturing varieties, respectively. There was significantly postitive correlation between the length of vegetative stage and the grain yield. The mean temperature during ripening period was significantly correlated with the grain yield and the percentage of filled grains. The length, width, and thickness of leaf increased with earlier transplanting and the elongation degree between upper and lower leaves showed the same tendency. The productivity of dry matter and the translocation rate of photosynthate to spikelet decreased with late transplanting mainly due to low temperature. LAI was also influenced by transplanting date showing close correlation with yield. Early transplanting was desirable for assimilation and dry matter accumulation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.359-367
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• 1985

This experiment was conducted to study effect of cold water damage on some growth characters related to source and sink at reproductive growth stage in Jinan (sea level 303m). The cold water irrigation duration had irrigated 4, 8 and 12 days at panicle formation stage and reproduction division stage compared to perennial water irrigation. Cold water irrigation shortened culm length and panicle length and degree of panicle exsertion. The shortening effect appeared great at lower internodes when treated at panicle formation stage but at higher internodes when treated at reduction division stage. Cold water irrigation decreased the number of secondary branches and spikelets per panicle, and increased the number of degenerated spikelets being high degeneration when treated at panicle formation stage. Spikelet sterility and impediment of grain filling were affected by duration of cold water irrigation being great when treated at spikelet primodium differentiation stage and reduction division stage in particular. Grain weight was also reduced. Significant relationship existed between spikelets sterility, grain filling and yield. The degeneration of secondary branches and spikelets correlated with leaf area but spikelet sterility and yield with culm length, panicle length and panicle exsertion.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.87-99
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• 1991

The experimental growth regulators Hoe78784 and PP-333 significantly reduced lodging in all rices. However, they did not significantly affect the crop vegetative characteristics and yield components, except by decreasing plant height when both growth regulators were applied at booting stage. Grain yield of IR21820-154-3-2-2-3 increased due to reduced lodging when Hoe78784 and PP-333 were applied at booting. These growth regulators increased the thickness and diameter of the culm. Applying CCC did not affect lodging in all test varieties. CCC-treated varieties and the control showed lower number of vascular bundles and culm thickness and diameter of the third and fourth internodes. Hoe78784 and PP-333 significantly reduced internode length from the second to the third internode in short-statured varieties. In tall varieties. reduction extended up to the fourth internode. Culm N content of the varieties did not significantly differ among treatments, except in IR8. Culm P content also did not differ significantly among treatments. although K and Si content was the highest than control when Hoe78784 was applied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s01
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• pp.4-15
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• 1989

The objective of this paper is to compare and summarize the procedure and effectiveness of some bioassay systems and to point out ways to obtain reliable results from each bioassay. Detailed C:escriptions were given for those widely-adapted bioassay methods, such as mungbean rooting (auxin), Avena first internode straight growth (auxin), dwarf rice growth (gibberellin), dwarf pea epicotyl elongation (gibberellin), radish cotyledon expansion test (cytokinin), and tobacco stem pith callus growth (cytokinin), and the effects of various plant growth regulators including some recently introduced growth retardants (Paclobutrazol, Uniconazol, etc.) were also summarized.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.239-242
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• 1981

Soil stamping made plant type of barley prostrated root system developed well in deeper soil layer, the chlorophyll content of leaf high, ethylene production in leaf high and elongation of lower internode inhibited. Overall result was higher grain yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.383-390
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• 1993

This experiment was carried out in the green house at Tokyo University of Agriculture in 1992 to investigate the relationship between lodging resistances and specific morphological characters and to examine the effects of nitrogen top-dressing and growth retardant on changes of the endogenous ethylene content in rice plant. Inabenfide did not affect significantly yield, yield component, chlorophyll content, and $CO_2 assimilation but, decreasing plant height when growth regulators were applied at booting stage, decreasing internode elongation, and increasing culm thickness and diameter of the third and fourth internode. While, nitrogen top-dressing usually showed to effect increasing vegetative growth such as plant height, tiller number, and morphological characteristics but, were not significantly affected the chlorophyll content and $CO_2 assimilation. Ethylene evolution was dramatically changed with nitrogen top-dressing and growth retardant. Application of Inabenfide at 15 days before heading inhibited ethylene evolution in the all nitrogen levels. Higher nitrogen top-dressing showed higher ethylene evolution than that of low nitrogen level. High positive correlation was detected between nitrogen application and ethylene evolution.

• Research in Plant Disease
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• v.10 no.1
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• pp.48-52
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• 2004

We investigated the effect of infection time of CGMMV on the growth and quality of watermelon and cucumber plants. The effect (damages by CGMMV) was estimated on the watermelon where CGMMV had been inoculated at different growth stages, vegetative (transplanting stage, vegetative growth stage) and reproductive growth stage (fruiting stage and fruit hypertrophy stage). In the case of cucumber, CGMMV was inoculated at transplanting stage and Erst flowering stage, respectively. When watermelon was infected with CGMMV at vegetative growth stage, vine length, internode length, leaf area, and fruit weight of the plants largely decreased compared with control plants, while the infected plant growth was not very different from control plants when it was infected at reproductive growth stage. Brix of the fruit of watermelon also decreased when the plants was infected with the virus earlier than fruiting stage. The occurrence of 'Pisubag', internal discoloration and decomposition of watermelon fruits, tended to be increased as earlier infection time with CGMMV In the case of cucumber infection time with CGMMV did not influence earlier growth of the plants, but did later growth showing that plant height, vine length, internode length, number of leaf, leaf wide, and leaf length of the plants decreased as infection time became to be earlier.

• Research in Plant Disease
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• v.9 no.1
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• pp.52-56
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• 2003

It was conducted to investigate the effect of rice downy mildew (RDM) infection to plant growth and yield components in water seeding stage, and to screen of varietal resistance to downy mildew. Being infected by rice downy mildew, chlorotic spot appeared in the leaf and leaf length was shortened. As the infected rice was growing, internode was not elongated properly and was deformed, and then panicle was not arised or mal-formed. Plant height of infected rice was shortened at all growth stage, and while the number of tillers of infected rice was more decreased than that of healthy plant before maximum tillering stage, and that of infected rice was more increased after heading stage. While the number of internode of infected tiller was much increased than that of healthy tiller internode length of infected tiller was shorter. As the rice infected by RDM severely, the number of panicles per square meter and ripening of rice was more decreased and yield of rice was extremely much decreased. As result of the varietal resistance screening with rice seedling, Geyh-wabyeo and Donjinbyeo were resistant varieties to downy mildew.