• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.721-726
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• 2021

Plant cells have a totipotencial capacity, the ability of each cell to produce a new complete individual through development. By applying this, several technologies are being developed for widespread application of somatic embryogenesis by processing hormones in vitro as a method of propagation of plants. In order to use this technology, in Kalanchoe pinnata, a plant capable of asexual reproduction with more regular cell division, kinetin belonging to cytokinin and picloram among hormones belonging to auxin were added in combination and treated for 8 weeks, and then the typical performance was evaluated. As a result of our experiment, the rooting effect in leaf slices showed a 70% incidence rate at a picloram concentration of 0.1 mg/L. It has been proven that a concentration difference of 1:5-1:10 in the ratio of kinetin and picloram is effective. It is the experimental result that the effect of auxin is essential for the development of Kalanchoe roots. As for the effect of shooting, the incidence rate was 60% at the picloram concentration of 0.5 mg/L. The kinetin concentration from 0.5 and 1.0 mg/L and has a significant effect on development. It has been proven that the ratio of kinetin to picloram is effective with a concentration difference of 1:1-1:2. These results show that the combination of cytokinin and auxin is crucially important for shooting. It is thought that it can be the basis of a technology for inducing mass proliferation in vitro by inducing direct organogenesis with a combination of hormones.

• Korean Journal of Plant Resources
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• v.34 no.2
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• pp.156-165
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• 2021

The in vitro regeneration was established, and the genetic stability among the mother plants (control) and the micropropagated green plants was evaluated using ISSR markers in Imperata cylindrica 'Rubra', Poaceae which containing important bioenergy plants. Green shoots were multiply induced from growing point culture via callus on MS medium supplemented with 0.01 mg/L NAA and 2 mg/L BA, and the shoots were proliferated on the MS medium with rooting. Rooted plantlets were transplanted to the pot with 100% survival rate. Using ISSR markers, somaclonal variation was analyzed in eight mother plants (control), ten green-regenerant cultivated at culture room (ReR) and ten green-regenerant cultivated at field condition (ReF). All ISSRs produced a total of 97 bands, and the scorable bands varied from one to seven with an average of 4.4 bands per primer. The polymorphism rate of ReRs and ReFs was 4.1% and 3.1% respectively, showing higher rate than that of control (0%). The genetic similarity matrix (GSM) among all accessions ranged from 0.919 to 1.0 with a mean of 0.972. According to the clustering analysis, ReFs and mother plants were divided into two independent groups. The results indicate that no clear genetic diversity was detected among regenerated plants, and ISSR markers were useful tool for identification of somaclonal variation of regenerants.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.212-220
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• 2022

When it comes to single node leafy stem cuttings of rose (Rosa hybrida), environmental management such as air temperature, relative humidity, and light affect productivity. In order to investigate the effect of air temperature and relative humidity on the cutting success rate and rooted cuttings quality, a transparent airtight box was used to implement a closed system. We have also tried to find out the most effective photoperiod and the number of leaflets in closed system using artificial light (white LED, 104.0 µmol·m^-2·s^-1 photosynthetic photon flux density). The first experiment was conducted for a total of 6 weeks under 4 airtight period conditions. The number of roots and longest root length decreased as the airtight period increased. But there were no significant differences in the survival rate, shooting rate, and rooting rate according to airtight periods. In the second experiment the results indicated that survival and shooting rate were significantly affected by the photoperiod (0/24, 2/22, 4/20, 8/16, and 16/8 h), the number of leaflets (0, 2, and 4 leaflets) of the cuttings and their interaction. The survival rate was the highest in the 16-h day length and 4 leaflets. By considering survival rate and shooting rate with energy efficiency, the 8-h day length and 2 or 4 leaflets were judged to be the most effective.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.4
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• pp.287-293
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• 1991

The root-mat formation of infant rice seedlings (8- to 10-day-old) is sometime not enough for machine transplanting because of the too-short nursery period. This experiment was conducted to elucidate the effect of metalaxyl seed-soaking treatment in the mixed solution of metalaxyl, seed disinfectant and insectcides on the root-mat formation of infant rice seedling in machine transplanting. The rice seeds of Odaebyeo were soaked in the mixed solution of metalaxyl, prochloraz and insectcides. with the recommended concentrations for 24 hours at room temperature. Seeding rate was 220g per seed tray (30 x 60 x 3cm). Metalaxyl (25% wettable powder), a fungicide. was used in 1. 000 times dilution as a promoting substance on the root-mat formation. Generally, the metalaxyl-treated seeds markedly increased the root number and length, and rooting activity of infant rice seedlings as compared with the control, thus the root-mat formation was excellent. When the rice seeds were sterilized by the mixed solution of prochloraz and insectcides, metalaxyl could be used together for increasing root-mat rormation of infant rice seedlIngs due to no interaction among agro-chemicals used. Seedling damping-off and physiological seedling rot were also controled in the seedlings of metalaxy-treated seeds. The root-mat of metalxyl-treated seeds had higher hardness and tension than control in terms of physical properties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.230-236
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• 1992

To study the effects of different nursing methods and transplanting on the growth of the rice plant(Oriza sativa L.hn southern region of Korea, Kumo-byeo, Palgong-byeo and Dong-jinbyeo were transplanted from April 20 to July 20 with 15 days intervals as 8 days seedling (infant rice), 25 days box seedling for machine transplanting and 45 days conventional seedling, respectively. No. of leaves at transplanting were in order of 45 days seedling>25 days seedling>8 days seedling. In 25 days seedling, they were increased as transplanting dates were later from April 20 to June 5, and in 45 days seedling, it showed same tendency until June 5 with Dongjinbyeo, June 20 with Palgong-byeo and Kumo-byeo. Root activity according to the $\alpha$-naphthylamine oxidation activity and rooting activity were higher in order of 8 days seedling>25 days seedling>45days seedling. Panicle formation initiated after maximum tillering stage as transplanting at April 20 with 8 days seedling and 25 days seedling, but it intiated before maximum tillering stage as transplanting at July 20 in Kumo-byeo. and in Palgong-byeo intiations of panicle formation were shown after maximum tillering stage as transplanting until May 20, but June 5 in Dongjin-byeo. However, there was no significant tendency with 45 days seedling. Missing hill ratio were less than 5% as transplanting with 8 days seedling and 25 days seedlingregardless of transplanting periods or varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.59-67
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• 1992

The duration of raising seedling of infant rice seedling(IRS) in machine transplanting is 8 to 10 days. This experiment was conducted to investigate the minimum duration of IRS's raising seedling and its method by the combination of several treatments such as plant growth regulator, root-break-seat and temperature. The rice seeds of Hwaseongbyeo was soaked in the solution of metalaxyl for 24 hours at room temperature. Metalaxyl (25% wettable powder), a fungicide, was used in 1, 000 times dilution as a promting substance on the root-mat formation of IRS. The application of fungicide in the nursery soil for the controlling of damping-off and physiologyical seedling rot was omitted due to the metalaxyl seed-soaking treatment. Seeding rate was 220g per seed tray (30$\times$60$\times$3cm). To promote the root-mat formation of IRS, the sheets of polyethylene vinyl and absorptive paper were placed bottom the seed tray. The root-mat formation of IRS was promoted at higher temperature and longer duration of raising seedling. The metalaxyl-treated seeds markedly increased the root length and rooting activity of IRS as compared with the control, thus the root-mat formation was excellent. The absorptive paper with polyethylene vinyl as root-break-seat showed a better root-mat formation compared with control, polyethylene vinyl, alone. The minimum duration of raising seedling of IRS was 5 days after sowing based on the root-mat formation and seedling height under the condition of metalaxyl seed treatment, absorptive paper with polyethylene vinyl as a root-break-seat and the raising seedling temperature 30/2$0^{\circ}C$ (day /night).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.383-393
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• 1991

Lodging of rice plant is the most important damage by unfavourable weather conditions in rice cultivation. High levels of nitrogen application and growing of Japonica rice variety is one factor to increase the lodging damage. Lodging of rice plant decreasing grain yield; 34% at milky. 21% at dough. 20% at yellow stage. decreasing grain Quality. increasing green rice. and increasing labor cost to harvest. To decrease lodging damage. the lodging resistant varieties will be selected and cultural practices such as amount and time of nitrogen application. planting density. water management. and disease and pest control methods have to be study for the short and strong culm. and good rooting system. Also. application methods such amount and time of plant growth regulators and new types of chemicals will be develop for the reducing lodging of rice plant. To decrease the lodging damage in direct seeding cultivation. first identifying the differences of lodging mechanisms between hand transplanting and direct seeding, second establish the suitable direct seeding methods such as seedling establishement. fertilization. and water menagement.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.434-439
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• 1989

This study was carried out to investigate the minimum days for raising infant rice seedling with different temperature (day/night $^{\circ}C$ : 20/12, 25/18, 30/20) and to compare with seedling growth and rooting ability at 10 days after transplanting with endosperm-intacted and removed seedlings. The minimum days for raising infant rice seedling was shown differently with different temperatures, thus there were turned out by mat formation to be 10 days at 20/12$^{\circ}C$ (day/night), 8 days at 25/18$^{\circ}C$ and 6 days at 30/20$^{\circ}C$, respectively. Seedling height, leaf number and dry weight of top part at the minimum days for raising infant rice seedling were 8-12cm, 1.5-1.7 leaves and 6.9-7. 5cm per seedling, respectively. The seedling growth at 10 days after transplanting was better at high temperatures (25/18$^{\circ}C$) than low temperature (20/12$^{\circ}C$) at transplanting, and the growth of infant rice seedling with endosperm -intacted was better than that with endosperm-removed. This tedency was shown significantly in transplanting at 20/12$^{\circ}C$ (day/night) of 4 days seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.545-553
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• 1993

The metalaxyl seed-soaking treatment markedly increased the root-mat formation of the young rice seedling(8- to l0-day-old) for machine transplanting. This experiment was conducted to find out a possible rooting mechanism of the young rice seedling in relation to the exogenous metalaxyl seed-soaking treatment. The rice seeds of Hwaseongbyeo variety were soaked in the solution of metalaxyl for 24 hours at room temperature. Metalaxyl(25% wettable powder), a fungicide, was used at the concentration of 200ppm as a promoting substance on the root-mat formation of the young rice seedling. Seeding rate of the young rice seedling was 220g per seed tray(30${\times}$60${\times}$depth 3cm). Metalaxyl seed treatment was highly effective in root initiation and elongation of the young rice seedling in terms of root activity, the number and length of root, and amino acid content of roots. The exogenous metalaxyl application would also increase the chlorophyll content and photosynthetic rate in the young rice seedling. Those factors resulted in vigorous root-mat formation of the young rice seedling. In particular, alanine is a lead compound of metalaxyl which biochemically plays an important role in energy intermediate of the rice plant. Alanine conjugation with a glucose (N-${\beta}$-glucoside) is probably the mechanism in enhancement of initiation and elongation of rice roots of young rice seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.385-397
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• 1982

The climatic impacts have been the environmental constraints with soil characteristics to achieve self sufficiency of food production in Korea. In this paper, the distribution and appearance of impacts and the changes in climatological status due to recent trend of early transplanting of rice are widely discussed to derive some countermeasures against the impacts, being focussed on cultural A long term analysis of the climatic impact appearances of the last 74 years showed that drought, strong wind, flood, cold spell and frost were the major impacts. Before 1970's, the drought damage was the greatest among the climatic impacts; however, the expansion and improvement of irrigation and drainage system markedly decreased the damage of drought and heavy rain. The appearance of cold damage became more frequent than before due to introduction of early transplanting for more thermophilic new varieties. Tongillines which were from Indica and Japonica crosses throw more attention to cold damage for high yields to secure high temperature in heading and ripening stages and lead weakness to cold and drought damage in early growth stage after transplanting. The plants became subject to heavy rain in ripening stage also. For the countermeasures against cold damage, the rational distribution of adequate varieties according to the regional climatic conditions and planting schedule should be imposed on the cultivation. A detoured water way to increase water temperature might be suggestable in the early growth stage. Heavy application of phosphate to boost rooting and tillering also would be a nutritional control method. In the heading and ripening stages, foliar application of phosphate and additional fertilization of silicate might be considerable way of nutritional control. Since the amount of solar radiation and air temperature in dry years were high, healthy plants for high yield could be obtained; therefere, the expansion of irrigation system and development of subsurface water should be performed as one of the national development projects. To minimize the damage of strong wind and rainfall, the rational distribution of varieties with different growing periods in the area where the damage occurred habitualy should be considered with installation of wind breaks. Not only vertical windbreaks but also a horizontal wind break using a net might be a possible way to decrease the white heads in rice field by dry wind. Finally, to establish the integrated countermeasures against the climatic impacts, the detailed interpretation on the regional climatic conditions should be conducted to understand distribution and frequency of the impacts. The expansion of observation net work for agricultural meteorology and development of analysis techniques for meteorological data must be conducted in future together with the development of the new cultural techniques.