• Journal of Plant Biology
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• v.17 no.1
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• pp.15-21
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• 1974

The most commonly grown economical and flue-cured tobacco cultivar Yellow Special A was used in pot-culture tests in order to study Ethrel (2-chloroethyl phosponic acid) effects on accelerating maturity of tobacco leaves in relation to the most adequate level of the chemical useful for field growing, nitrogen level in soil for the most pronounced response, and the most suitable spray period during the growth stages of pre-, post- and topping periods. The following conclusions, thus, were obtained from the present studies; 1. 500ppm Ethrel spray was reconfirmed to be adequate in the practical applications, although the extent of yellow-ripening of tobacco leaves was increased as the Ethrel level increased. The highest leevel treated resulted in causing chemically damaged lesions on leaves and early defoliation. 2. Ethrel-treated leaves showed deeper yellowish tinge to them than those without treatment, while different levels of the chemcial had less influence on the tinge. 3. An adequate level of nitrogen supply to plants favored the Ethrel response, whereas either very low or high level of nitrogen in the soil lowered the chemical effect on accelerating the yellow-ripening. When carbohydrates versus total nitrogen ratio became relatively high, the condition brought out some outstanding Ethrel effects. 4. Chlorophyll level of leaves increased as soil applications of nitrogen level increased, and that also increased carotenoid level of the tobacco leaves. Ethrel-treated leaves showed deeper orange tinge than those without treatment, while the highest level of nitrogen application showed the deepest orange tinge to tobacco leaves. 5. Pre-topping treatment (12 days before topping and flowering) resulted in almost no Ethrel response, and that treatment right on the day of topping, showed response of yellow-leaf ripening at nearly bottom-half leaves of a tobacco plant. The post-topping treatment (12 days after topping) made plants showing full response of Ethrel from bottom to the top leaves of tobacco plant in accelerating the leaf maturity. 6. The extent of Ethrel responses on accelerating yellow-ripening of tobacco leaves was discussed for the modifying influences brought about by certain environmental factors. Discussions were also made about the possible practical applications (particularly for pre-rice planting) and quality difference that may be caused by such growth environments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.97-124
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• 1976

To find out the most effective method of treatments for the induction of sprouting of dormant seed potato pieces for the fall crop production of Irish cobbler, this experiment was carried out with sprout inducing bed and field performance trial. In GA treatments, about 10 days were required to sprout and resulted uniform and thin 3-4 sprouts per tuber piece, but sprouts were slender and rooting was not observed. In Ethrel treatments, 20-25 days were required, and sprouts were inferior than that of GA treatment in uniformity of sprouting, and percentage of rotten pieces and of healthy sprouted tuber pieces, but number of sprouts per tuber pieces was low, being 1-2, and sprouts were short, thick, and healthy, and showed good rooting. In GA and Ethrel mixture treatments, 1-2 more days were required to sprout than GA treatments, but sprouts were relatively healthy, and other sprouting pattern were like that of GA treatments. In Ethylene chlorohydrin and 6-Benzyl-adenine treatments, sprouting was like that of Ethrel treatments, but much more days were required than Ethrel treatments and tendency of severe rotting was observed. Optimum treating methods of promising chemicals found to be 1-2 and 2-5 ppm GA solution, 500 and 1000-2000 ppm Ethrel solution, and 1-2＋250-500 and 5＋250-500 ppm GA and Ethrel mixture solution for 60 min. treatment of tuber piece and whole-tuber, respectively. Induction of sprouting in dry and hot time resulted severer rotting of tuber pieces during the induction of sprouting and with the advancement of dormancy, being delayed in date of treatment, tendency of promotion of sprouting and rooting was observed. When sprouted tuber piece was transplanted at the same date, yields were in order of Ethrel, GA and Ethrel mixture, and GA treatment, indicating the correlation between yield and healthiness of sprout and rooting status of sprouted tuber piece. In all treatments, earlier transplanting resulted higher yields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.115-121
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• 1975

To achieve self-sufficiency in good production, cotton should be grown after barley in the southern part of Korea. But, this cropping system reduces cotton yields and fiber qualities in the current leading cotton varieties because of the short frost-free growth period. Ethrel-treated plots shortened the time to open boll by about 20days, increased the percentage of open bolls before the first frost from 38% to 93% and increased yield by 15-38%. There are not significant differences in staple length, tensile strength of the fiber, single bollweight, 100 seeds weight and germination percentage of the seeds between Ethrel-treated and untreated plots. Ethrel should be recommended to the farmers growing cotton after barley harvest.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.7-14
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• 1972

Four treatment leveles(check 500, 1, 000 2, 000ppm) of Ethrel were applied to barley and wheat grown in greenhouse and fields at three stages (preboot, boot, afterboot) of growth in orderd to induce male sterility and to evaluate possibility of practical $F_1$-hybrid-seed production as gametocide. The results are summarized as follows. 1. The shortening plant height, especially the first internode length. spike length and decreasing 1, 000 seeds weight and induction of male sterility, were observed with all Ethrel theatments. The earier the stage of spraying at the boot and the higher concentration of Ethrel, the greater effects were observed. 2. The most practical level of inducing male sterility occurred ranging from 1, 000-2, 000ppm applied at all stages, while with increasing maturity, greater concentration of Ethrel were required to induce the same level of male sterility. .3. Great differences for male sterility per spike in bagged and unbagged spikes were shown with all treatments indicated ovary receptiveness, and that out-crossing has taken place, 4. Ethrel treatment induced more practicable extent of male sterility in barley than wheat. This results indicated that $F_1$-hybrid-seed production in barley with gametocide appears feasible if high combining ability lines were selected for increased out-crossing ratio. 5. There seemed to be no indication of additive surfactant influence on the Ehrel action in the present studies, and showed an interest on further studies on this matter.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.483-487
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• 2001

This study was conducted to examined the effects of TIBA and ethrel on podding rate, percentage of seed numbers per pod, and seed yield of black soybean. The black soybean variety “Geomjeongkong 1” was used. TIBA of 50, 100, and 150 ppm and ethrel of 500, 1,000, and 1,500 ppm were applied at V6 (fifth leaf stage), V8 (seventh leaf stage), and R1 (flowering stage). The podding rate was increased by the treatment of TIBA at R1 stage while it was decreased by ethrel at all growth stages. Compared with control, TIBA decreased 100 seed weight a little bit but ethrel increased it slightly, on the contrary. Both TIBA of 50 ppm and ethrel of 500 ppm increased the sued yield by 8 to 28％ compared with control regardless of growth stages of application; the highest seed yield was obtained at V6 stage of application of 50 ppm in TIBA and 500 ppm in ethrel, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.107-114
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• 1975

To develop the technics of generation shortening for the breeding of rape oil composition. effect of the ethrel and hydroperoxide treatment for the increasing of germination ability during maturing period was investigated. It was the most effect ire for a generation shortening that the seeds after, 10 days treated with $H_2O$$_2$-0.5% and 2, 000ppm of ethrel and after 15 days treated with $H_2O$$_2$-0.5% and 500ppm of ethrel on 15 day after flowering were germinated 76% and 90% respectively. It suggested that effect of ethrel and hydroperoxide was multiple and 4-5 generations could pass in a year because one generation needed only 66-71 days.

• Journal of Sericultural and Entomological Science
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• v.33 no.1
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• pp.6-8
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• 1991

The study was carried out to investigate the effect of ethrel (2-chloroethylphosophonic acid, 39%) on the graftages quality. Ethrel was sprayed 5 days interval from October 10 to October 30 at 6 places (Suwon (I), (II), Chungju, Kongju, Wanju, Jangsong). Spraying conentration was 1, 000 ppm (400 times dilution). 1. Spray took 3.3 hrs and 500 m of ethrel on 10a eara. 2. The passed rate of graftages decreased 5-8% on the treatments earlier spray than on October 20. 3. New shoot length and number of shoot of the ethrel treatments were the same as the natural leaf falling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.163-168
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• 1982

Tobacco seedling which were sown 20 days earlier than conventional, both at 4-5 and 7-8 leaf stages, were once sprayed with ethrel (0, 500, and 1,000 ppm concentrations) and transplanted simultaneously to investigate the subsequent effects. The number of leaves and days to flower were tend to decrease when seedlings were treated at an early developmental stage than at later stage. The highest yield was obtained from seedlings treated with 500 ppm of ethrel at the 4-5 leaf stage, showing 40% increment above conventional seedlings, partly due to more number and bigger size of the leaves. Finally possible mechanisms for the result were discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.45-51
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• 1977

The studies were carried to know the effects of GA$_3$, Ethrel and $H_2O$$_2$ on dormancy and germination in ginseng seeds. GA$_3$ stimulated the embryo growth and increased dehiscent (Kaekapp) ratio of the seeds for more than Ethrel and $H_2O$$_2$ GA$_3$ not only increased germination ratio but also shortened the period of germination. Ethrel and $H_2O$$_2$ showed no effects on the germination and there were no significant differences among the treatment levels of GA$_3$. The slow germination of ginseng seeds seemed to be mainly due to the dormancy of endosperm or seed coat rather than of embryo.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.222-232
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• 1976

Two different cultivars of barley, with either the ordinary-level or double-strength nitrogen application, were grown in two districts simultaneously, in order to study the extent of dwarfing in plant height, lodging and grain-yield increase with ethylene-releasing agents (Ethrel and dl-methionine alone or in combination). The shorter the plant height, the less the extent of lodging and the grain yield there were. With 500ppm Ethrel, 10% grain-yield increase was attained without showing apparent lodging, irrespective of the level of nitrogen applied. The double-strength nitrogen application resulted in severe lodging more than the ordinary-level and control, and lower grain yield accordingly. Consideration for importance of barley lodging in Korea today and the controlling measure with ethylene treatment for dwarfing, and yield increase by increased nitrogen application, were discussed.