• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.186-186
• /
• 2017

Relay intercropping system of direct seeded rice and winter cereal is labor saving cultivation and has high land use efficiency in Japan. In this system, rice seeds are direct seeded into inter-row space of winter cereals (wheat or barley) in March or April. If the direct seeding of rice is conducted before stem elongation phase or using suitable seeder, these are little effect to yield of winter cereals. Though the seeds are generally thiuram treated, it's a matter that seedling establishment rate (SER) of direct seeded rice is low and unstable. The cause of low SER has not been revealed. In present study, with the aim to reveal causes of low SER, we conducted experiments and investigated the SER, and analyzed some factors that might affect SER. Experiment1: In 2015, 2016, we buried rice seeds underground, and investigated the transition of the seed survival rates (SSR). Seeds were thiuram-treated or non-treated. In 2 periods, SSR of thiuram-treated seeds were significantly higher than non-treated seeds. In 2016, thiuram-treated seeds were high in SSR (almost 75%) at April 30th, but low SER (10~27%) after harvest of winter cereals. Therefore, almost all of seed death might have been happen after germination. Analysis 1: We investigated the SER and cultivation conditions in Ibaraki pref. for several years. Meteorological factors were referred from the nearest point of AMeDAS. From mean temperature (MT) among 5days after and before the day, we divided the period of seeding ~June 20 to phase1~4. We defined each phase as below; Phase1: $MT{\leq}10^{\circ}C$, Phase2: $10^{\circ}C<MT{\leq}15^{\circ}C$, Phase3:$15^{\circ}C<MT{\leq}20^{\circ}C$, Phase4: $MT>20^{\circ}C$. We analyzed the correlation of SER and meteorological factors by each phase. Total number of days in phase 1~4 was significantly negative correlated with SER. In phase1, total rain fall and number of soil wetting days were significantly negative correlated with SER. In phase2~4, only MT was significantly positive correlated with SER. This result suggested that rainfalls in phase1 declined seed vigor to emergence from soil surface, by repeated water absorption and re-dry. From these present studies, it was suggested that one of factors of low SER of direct seeded rice in relay intercropping system is changing of water condition by rainfalls in phase1 ($MT{\leq}10^{\circ}C$). To improve SER, it's necessary to consider something seed treatments such as prevent water absorption during phase1. However, 58~60% of seeds seemed to die during May. It's suggested that, if seeds are thiuram treated, almost all of seeds can germinate underground, but the seed vigor to emergence from soil surface are insufficient. Further studies are needed to reveal the rest causes that is happening during emergence from soil surface.

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.4
• /
• pp.239-256
• /
• 1997

Plants belonging to the category of 2n apomixis or agamospermy form embryos and seeds without the processes of normal meiosis and syngamy. Seeds produced in this way have identical genotype of their maternal parent. Three different types of agamospermy are recognized: diplospory, apospory, and adventitious (adventive) embryony. $F_1$ hybrid cultivars cannot be used as seed sources in the next ($F_2$) generation because this generation would be extremely variable as a result of genetic segregation. Hybrid vigor is also reduced in the $F_2$ generation. Therefore, parental stocks for hybrid seed production need to be maintained and cross must be continuously repeated. Agamospermic 2n apomixis would make it possible to fix the genotype of a superior variety so that clonal seeds faithfully representing that genotype could be continuously and cheaply produced independent of pollination. That is, $F_1$ hybrid seeds could be produced for many generations without loss of vigor or genotype alteration. Production of apomictic $F_1$ hybrid seed would be simplified because line isolation would not be necessary to produce seed or to maintain parental lines, and the use of male-sterile lines could be avoided. Overall, apomixis would enable a significant reduction in hybrid seed production costs. Additionally, the production of clonal seed is not only important for seed propagated crops, but also for the propagation of heterozygous fruit trees and timbers. Clonal seed would help avoid costly and time-consuming vegetative propagating methods that are currently used to ensure the large-scale production of these plants. Apomixis is scattered throughout the plant kingdom, but few important agricultural crops possess this trait Therefore, most research to date has centered on introgressing the trait of apomixis into agricultural crops such as wheat, maize, and some forage grasses from wild distant relatives by traditional cross breeding. The classical breeding approach, however is slow and often impeded by many breeding barriers. These problems could be surmounted by taking mutagenesis or molecular approach. Arabidopsis thaliana is a tiny sexually reproducing plant and is convenient in constructing and screening in molecular researches. Male-sterile mutants of Arabidopsis are particularly suitable genetic background for mutagenesis and screening for apomictic mutants. Molecular approaches towards isolating the genes controlling the apomictic process are feasible. Direct isolation of genes conferring apomixis development would greatly facilitate the transfer of this trait to wide variety of crops. Such studies are now in progress.

• Journal of Korean Society of Forest Science
• /
• v.83 no.2
• /
• pp.229-238
• /
• 1994

Issues of declining growth and vigor in forests are major concerns in many areas around the world, especially in response to predictions in the 1980s of widespread forest declines. This paper summarizes the current state of knowledge for forests in North America, Europe, and East Asia. Forest declines near point-sources of pollution(such as metal smelters) have been well recognized for a century, but evidence of widespread impacts away from point-sources remains relatively uncommon. In North America, significant forest decline has resulted from high concentrations of ozone near Los Angeles, California, and around Mexico City. Some high-elevation forests of red spruce in the eastern U.S. have declined in the past 20 years ; evidence indicates a role of low-pH fog in reducing they cold-tolerance of spruce. In Europe. most attention has focused on Norway spruce stands that developed yellow foliage, needle loss, and in some cases mortality. This syndrome appears to be related generally to an inadequate supply of magnesium, perhaps coupled with a very high supply of nitrogen. Despite localized areas that show declining trees, overall stand growth and standing biomass in Europe increased from. 1970 to 1990. Much less information is available for East Asia. Many industrialized regions in China have a pH of rain <4.5, and some connections between pollution and forest decline have been suggested. Pollution impacts on forests near cities in Korea include needle chlorosis, reduced needle retention, and declining species diversity. Overall, temperate forests show no widespread declines, and no evidence of substantial effects of pollutants on forest growth or vigor. Small areas showing declining forests may indeed demonstrate pollution impacts, and may provide cause for concerns about future impacts on larger areas.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.3
• /
• pp.285-294
• /
• 1994

Dried top and root extracts of seven different weed species, fresh top and root extracts, and various concentrations of extract (0, 5, 10 and 15%, W/V) and residue rate (0.0, 0.25. 0.5, 0.75 and 1.0%) of velvetleaf (Abutilon theophrasti Medic.) were used to study their allelopathic effects on alfalfa in the laboratory and greenhouse. Top and root aqueous extracts of common lambsquarter (Chenopodium album L.), giant foxtail (Setaria faberii Herrm), redroot pig-weed (Amaranthus retroflexus L), velvetleaf, large crabgrass (Digitaria sanguinalis L), canada thistle (Cirsium arvense L.) and prostrate knotweed (Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, and vigor in alfalfa. Top growth extracts of weeds exhibited greater allelopathic effects than root extracts. Alfalfa test species, WL-320, responded significantly different to the various weed species extracts in terms of allelopathic effect. The regression slopes of various top extracts showed significant variation with respect to germination percentage. Velvetleaf (b=3.69) extracts were the most inhibitory, while large crabgrass (b=2.39) extracts had the least allelopathic effect on alfalfa. When compared the activity of fresh velvetleaf extract to that of dry velvetleaf extract, dry extract was more inhibitory to alfalfa germination and seedling growth. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Seedling emergence and survival percentage was inhibited by velvetleaf residue mixture treatment. Also, more of the toxic effects were observed from the dried top extracts, as compared to extracts from fresh top and root. These results demonstrate the allelopathic activity of different weed species extracts and suggest that weeds may affect crop growth and development due to the inhibitory effects of allelochemicals present in weed tissue.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.8
• /
• pp.4930-4941
• /
• 2014

This study had three purposes. First, the effects of job-related affective states on emotional labor (deep acting and surface acting) of employees engaging in service job were examined. Second, previous studies focused on the negative effects of emotional labor on job attitudes. On the other hand, this study dealt with not only the negative effects of emotional labor but also its positive effects. In particular, this study examined the effects of emotional labor on positive job attitudes, such as job commitment and job involvement, as well as negative job attitudes, such as exhaustion and cynicism. Finally, this study examined the mediation effect of emotional labor on the relationship between the job-related affective state and job attitudes. The data was collected from 150 employees working in 15 service firms in Korea. The results were as follows. First, the positive job-related affective state increased the deep-acting. On the other hand, negative job-related affective state increased surface-acting. Second, the main effect of deep-acting on positive job attitudes (dedication and vigor) was significant. In addition, the main effects of surface-acting on the negative job attitudes (exhaustion and cynicism) was significant. Finally, the mediating effect of deep-acting on the relationship between positive job-related affective state and positive job attitudes was significant. In addition, surface-acting mediated the relationship between negative job-related affective state and negative job attitudes. The theoretical and practical implications of this study are provided in the discussion session.

• The Korean Journal of Mycology
• /
• v.43 no.4
• /
• pp.253-259
• /
• 2015

Anthracnose caused by Collectotrichum acutatum is the most devastating disease of pepper plants in Korea. In this study, we evaluated the effect of selected antagonistic bacteria on control of anthracnose and plant growth promotion of pepper plants under field conditions. Four different bacterial isolates used in the current study were isolated from the pepper rhizosphere (GJ01, GJ11) and tidal flat (LB01, LB14) in previous studies. Four bacterial isolates, together with a control strain (EXTN-1), showed antifungal activity against C. acutatum in a dual culture assay. To test for plant growth promotion effect, seedling vigor index and growth parameters of pepper were measured under field condition. As a result, all four bacterial isolates were effective for improving plant growth promotion. The strain GJ01 was the most effective in improving the seedling vigor on pepper, but the strain GJ11 in increasing the pepper fruit yield. The incidence of anthracnose was inhibited in the range of 63.2~72.5% by treatment of four bacterial isolates. The current study indicated that the four bacterial isolates could be used as potential biological control agents of anthracnose disease of pepper.

• Korean Journal of Plant Resources
• /
• v.19 no.4
• /
• pp.480-487
• /
• 2006

This study was conducted to improve the germination percent and germination speed by seed priming using polyethylene glycol (PEG) 8,000 solution on Acer mono seed because it has low and irregular germination characteristics. Seed priming was carried out under 0, -0.25, -0.5, -1.0 and -2.0 MPa of water potential at $20^{\circ}C$ for 3 days. Primed seeds showed higher percent germination, germination speed, mean germination time (MGT) and germination performance index (GPI) than unprimed seeds. Especially, primed seed with -2.0 MPa of water potential had the highest germination properties. And primed seeds had a lower dormancy than the unprimed seeds. Relative growth rate and T/R ratio of seedling from primed seeds were measured to survey the effect of seed priming on the seedling vigor as well as seed germination. The seedlings from primed seeds at -2.0 MPa of water potential showed the highest relative growth rates of height and root collar diameter, however, the lowest value in T/R ratio. This study suggested that seeds priming at -2.0 MPa of water potential under $20^{\circ}C$ for 3 days enhanced not only the percent germination, germination speed, MGT and GPI but also the vigor and growth of seedlings in Acer mono.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.5
• /
• pp.577-583
• /
• 2016

Small-sized persimmons produced by high crop load are better accepted in the export markets. However, maintaining high crop load frequently results in weakness of tree vigor, deterioration of fruit quality, and increase of the risks for alternate bearing. This experiment was conducted to determine the combined effects of fertilization rate and leaf-fruit (L/F) ratio on container-grown 3-year-old 'Fuyu' persimmon trees. Application of 3.6-g N, 2.1-g $P_2O_5$, 2.7-g $K_2O$, 2.7-g CaO, and 0.6-g MgO was for the control fertilization rate (CF) and that of a 3-fold CF was for the high fertilization rate (HF). Commercial fertilizers were surface-applied to a container on July 6, July 17, and August 10 in three equal aliquots. Single tree for each fertilization rate was assigned for 12 L/F ratios (5, 6.3, 7.7, 9, 10.4, 13, 15.5, 18, 21, 24, 27, and 33) mostly by fruit thinning or rarely by defoliation on July 1. HF did not affect the yield, weight and soluble solids of the fruits but decreased skin color. As L/F ratio increased, yield decreased but average weight, skin color, and soluble solids of fruits increased. With HF, N and K concentrations in leaves, fruits, and shoots increased to some extent but soluble sugars in dormant shoots decreased. Many shoots were cold-injured with low L/F ratio especially at the HF. HF did not increase number of flower buds the next spring either on a shoot or on a tree basis but increased shoot length, compared with the CF. Increasing L/F ratio markedly increased number of flower buds and shoot growth the following year at both fertilization rates. Therefore, an appropriate combination of fertilization rate and L/F ratio should be necessary to maintain stable fruit production and tree vigor at high crop load.

• Journal of Sasang Constitutional Medicine
• /
• v.10 no.2
• /
• pp.163-180
• /
• 1998

In 1492 year, the corn originated in America continent had spread all over the world after spreading into Europe by Columbus. Since the Corn had a similar shape with adlai's one (Yulmoo(율무)), it had been written by the different name of adlai (Yulmoo) at the "訓蒙字會(Hun-mong-ja-hoe)(1527)". Therefore we should consider "Hun-mong-ja-hoe" is the first record of the corn and it is a significant historic record in the civilization exchange between the Orient and the Occident that this record has the only difference of around 30 years later after the spreading corn to Europe. However, this is on the assumption that it is correct for a scholar of Korean literature to persist in that '叡山本' of "Hun-mong-ja-hoe" could be considered as the first edition. The corn had been once classified as a same kind of the Chinese millet because the people had been recognized the corn as a similar group of the Chinese millet and the Indian millet. The Chinese millet contains a summer vigor and becomes as an ingredient of alcoholic drink. And we can find out that $C_4$ type plant (such as corn, Chinese millet, Indian millet, foxtail millet) mostly have a tendency to belong to the food for "Taeumin(太陰人)", because of its high energy efficiency, a flourishing absorption of fertilizing and a strong emission power. The fried corn with a strong summer vigor and a raised feature has a good effect to the treatment of the teethridge disease. And the tea of corn with an warm feature, thanks to its functions of making the stomach and intestines comfortably as well as urination, is a proper food for the 'Taeumin" who is apt to overeat themselves.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.4
• /
• pp.367-372
• /
• 2017

This work was conducted to identify sweet potato [(Ipomoea batatas (L.) Lam.)] cultivars showing high yield and processing suitability in the Jeonbuk region of Korea. Shoot-slips (30 cm in length) of 14 cultivars were planted with a planting density of $75{\times}25cm$ on May 30, and cultivated with black film mulching. Vine elongation at 30 days after planting was significantly increased (> 90 cm) in 'Dahomi' and 'Sinhwangmi', and was excellent (> 250 cm) 120 days after planting in 'Sinhwangmi', 'Shinyulmi', 'Daeyumi', 'Jinhongmi', and 'Yeonhwangmi'. The branch number per plant showed a dramatic increase in 'Shinzami' 30 and 120 days after planting. The leaf number per plant showed the highest increase in 'Shinzami' 30 days and in 'Sinhwangmi' 120 days after planting. Total weight, mean weight, and number of marketable tubers per plant were significantly higher 150 days after planting than that 120 days after planting. Marketable tuber yield at 120 days was high, over 2.5 ton/10a in 'Daeyumi', 'Dahomi', and 'Jeonmi', and was considerably increased, from 3.2 ton/10a to 3.5 ton/10a, 150 days after planting. Total weight of marketable tubers per plant and marketable tuber yield 120 and 150 days after planting had significant positive correlations with vine length and number of nodes 30 days after planting. Starch value was significantly higher 150 days after planting than that 120 days after planting. 'Daeyumi' and 'Jeonmi' had good growth vigor, high yield, and high starch content; 'Dahomi' also exhibited beneficial traits such as good growth vigor, high yield, and bright orange-colored flesh.