• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.352-362
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• 2023

Harvest time is one of the most important determining factors of seed quality, especially for species that produce seeds over irregular and long-term periods, such as Larix kaempferi. A cone collection plan must be established to increase seed production efficiency and stable mass production. We investigated seed qualities such as seed efficiency, germination rate, and T₅₀ (germination speed), with 7 or 8 cone collection times at a clonal seed orchard of L. kaempferi in Chungju between 2021 and 2022. A multivariate analysis was then performed for the collected data. In early August, decreases in the moisture contents and browning of cones were observed. These were followed by a decrease in germination rate, with a peak at the end of September, but no clear trend was observed. The later the cones were harvested, the better the seed vigor (T₅₀). However, the seed yield and efficiency decreased owing to increases in seed scattering and the number of insect-damaged seeds. As a result, the optimal time of seed harvest for the seed orchard was in early August. To produce uniform seedlings, insect damage must be reduced through timely control and harvest cones in early September. This shows that the degree of browning and moisture content of cones can be used as indicators of the timing of cone collection in L. kaempferi seed orchards.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.155-160
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• 2001

Changes in genetic diversity after seed-tree practice were simulated in test plantation of tulip tree at Sokdal-ri, Banwol-myon, Hwasung-gun, Kyungki Provence. I-SSR markers were analyzed in a total of 305 tulip trees. A total of 89 amplicon variants were observed by PCR with 9 I-SSR primers. Genetic diversity for 305 trees was relatively high (S. I. =0.4532). Individuals originated from the seed orchards in U.S.A. showed the highest level of genetic diversity (0.4530), those from Anyang showed the medium level (0.4152), and those from Cheonbuk showed the lowest (0.3929). Simulation of seed-tree practice accompanied by 2 consecutive thinnings was performed on the basis of morphological characteristics and planted distances of the individual trees, which left 37 trees as candidates for seed-trees. Decreasing rate of genetic diversity within seed sources was greatest for individuals from Cheonbuk (28.3%), moderate for those from Anyang (16.3%), and smallest for those from U.S.A. (8.0%). In spite of little difference in decreasing rate of individuals for the 3 seed sources (87.5~88.2%), large difference in decreasing rate of genetic diversity within seed sources might be due to difference in number of mother trees for the 3 seed sources. For example, whereas individuals originated from the seed orchard in U.S.A., which showed the smallest decreasing rate of genetic diversity, might be originated from relatively large number of mother trees, those from Anyang and Cheonbuk might be originated from relatively small number of mother trees. Although mean of 17.5% of the genetic diversity within seed sources was decreased through 2 consecutive thinnings, a decrease in genetic diversity for the whole individuals (37 trees) was only 6.1%. This observation suggests that the seed-tree practice on the basis of the criteria established in the present study may not result in great reduction in overall genetic diversity of the progenies.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.31-36
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• 1983

Flowering time of Pinus rigida Mill and Pinus taeda L, in an $F_1$-hybrid seed orchard was investigated for five years from 1971 through 1975. The two tree species flowered during late April to early May at the observation site, Flowering patterns of the two species of different sex of the same species changed yearly during the five observation years. Floral development of the two species appeared to depend largely on temperature factor during the period of the initiation of floral organs up to flowering provided that other environmental factors are normal. Six-days difference in flowing time between female inflorescence of pitch (flower later) and male inflorescence of loblolly (flower earlier) pines effectively isolated the two species reproductively on population levels. Not all of selected trees of the two species for their synchronized flowering appeared to be useful as parental trees for the establishment of $F_1$-hybrid seed orchards. With the result from this investigation the author suggested to use a modified simple recurrent selection method for pitch-loblolly hybrid pine breeding.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.239-249
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• 1982

The outlines of superior stands, including species mixed, age classes, canopies, and ecological conditions of the stands, were examined in the forests of west Germany, Sweden, and Netherland. The establishment schemes of tree seed orchards for the production of high genetic quality seed were also investigated in the present study. 1. The meteorological conditions, abundant in precipitation and high in relative humidity, prove it to be oceanic climate characteristics in the Scandinavia located in high latitude and north-western part of Europe. The photo periodical characteristics following to day-length and the frost times determine the patterns of tree growth and distribution as well as the tree adaptability due to bud-setting and bud-flushing in Sweden forest. 2. The European forests are generally characterized by dense multistoried forest type composed of upper stories of tall tree species such as Norway spruce, fir, Scots pine and beech, lower stories of shade tolerant poles and saplings of spruce, fir, beech, and floor vegetations covered with birch, oak and hornbeam etc. 3. The single tree selection method and group shelterwood method are commonly applied for silvicultural system but shelterwood method and clearcutting method practiced partially in limited area. Badischer Femelschlagbetrieb and Bayerischer Femelschlagbetrieb are popularized to the regeneration of Schwarzwald but selection method applied in part. 4. Tree cuttings are properly limited so as not to exceed annual increment volume for the sustained yield and the preservation of ecosystem in European forest management. Land preservation and recreation function are more interested with the promotion of wood production in the forest management. 5. Careful attentions are paid to the reforestation of the introduced exotic species, such as Douglas-fir, red oak, pines from America, Japanese larch, Italian poplar etc., with concern against the insect and pest damage, and the meteorological damage. 6. Some intensive studies on tree improvement, such as selection of plus tree, selection of plus stand for seed collection, provenance trial, progeny test of clone, hybrid seed orchard for clone complexing, are performed in the countries and the great part of the seed required for reforestation are supplied from the seed orchard established in Sweden and Netherland.

• Journal of Forest and Environmental Science
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• v.29 no.1
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• pp.1-14
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• 2013

Acacia mangium is an evergreen fast-growing tropical tree, which can grow up to 30 m tall and 50 cm thick, under favorable conditions. It is a low-elevation species associated with rain forest margins and disturbed, well-drained acid soils. It is native to Papua, Western Irian Jaya and the Maluku islands in Indonesia, Papua New Guinea and north-eastern Queensland in Australia. Due to its rapid growth and tolerance of very poor soils, A. mangium was introduced into some Asian, African and western hemisphere countries where it is used as a plantation tree. A. mangium has good quality wood traits, such as a comparatively low proportion of parenchymatous cells and vessels, white and hard wood, and high calorific value. Therefore, it is useful for a variety of purposes, such as furniture, cabinets, turnery, floors, particleboard, plywood, veneer, fence posts, firewood, and charcoal. It is also being used in pulp and paper making because it has good pulp traits, with high yields of pulp, quality of kraft, and produces paper with good optical, physical and surface properties. Because there are significant provenance differences in growth rate, stem straightness, heartwood formation and frequency of multiple leaders, the productivity and quality also varies depending upon environmental conditions, so genetic improvement programmes have been undertaken in countries like Australia, India, Indonesia, Malaysia, the Philippines, Taiwan and Thailand. The programme includes provenance identifications and testing, plus tree selection and clonal multiplication, establishment of seed orchards and hybridization. The phenology, reproductive biology, fruit characteristics, silvicultural practices for cultivation, pest and diseases problems, production of improved planting stock, harvesting, wood properties and utilization have been discussed in this paper.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.549-556
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• 1998

To develop the effective methods of flowering stimulation, Hinoki cypress (Chamaecyparis obtusa Sieh. et Zuec.) grafts growing in a seed orchard and in a clone bank in Southern Breeding Station of Cheju were applied with gibberellin treatments, and predicted the seed production potential. In the seed orchard, $GA_{4/7}$ 1.5cc was injected into the stem of drafts and sprayed whale tree crown with $GA_3$ 300ppm and $GA_{4/7}$ 300ppm. Un the other hand, in the clonal archives, drafts were given intrusion of $GA_{4/7}$ 1.5cc into the excised and open inner part of bark wind $GA_3$ 20mg and sprayed with $GA_3$ 300ppm. Additionally, grafts growing in the seed orchard were treated with gibberellins at 3 different periods of time and 3 different treatments during the growing season. The results obtained here are summarized as follows : 1. All of the applications of Gilbberellin promoted female flower formation. Among these, the treatment of intrusion of $GA_{4/7}$ 1.5cc into the excised and open inner part of bark was racist effective, followed by the spraying of $GA_3$ 300ppm. Similarly, the applications of gibberellin promoted male flower formation. 2. Regarding the time of applications, treatment on August 15 was more effective than those of August 31 and September 11 in the stimulation of female flowers. On the contrary, there was no significant difference in the number of male flowers among 3 different time treatments. 3. It was supposed that the application of the intrusion of $GA_{4/7}$ 1.5cc into the excised and open inner part of bark on August 15 showing the best effect in female flower formation can produce 22.12kg seeds per ha. 4. Considerable significant difference existed among clones for both female and male flower formations. 5. Flower formation, especially female flower formation, seemed to be partially associated with the genetic potential of individual trees.

• Korean Journal of Organic Agriculture
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• v.25 no.2
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• pp.445-460
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• 2017

This study was carried out for three years from 2013 to 2015 to investigate the actual condition of pest control of domestic persimmon organically cultivated farmers, to select environment - friendly pest control materials for major pests, and to conduct field test of established control system. The main cultivated cultivar of the reader farmer of organic cultivation was "Buyou" and sprayed organic agricultural material 9~17 times per year for pest control. The most harmful pests were anthracnose, bugs, persimmon fruit worm, and scales, etc. The control materials used were organic lime sulfur mixture, red clay sulfur, emulsifier, bordeaux solution, and self-made plant extracts using garlic, ginkgo nut and pine tree. The effective materials for controlling anthrax were lime sulfur mixture and red clay sulfur. Garlic oil + citronella emulsion, shrubby sophora seed extract + tea extract was effective to control Riptortus clavatus and Euproctis subflava. When installed 60 ea per 10a of mating disruption trap in a sweet orchard, the fruit setting rate was improved by 30%. The results of field test of control system to control 10 times a year in organically grown persimmons were able to harvest fruit of 70.7%. However, since any kinds of pesticides can not be sprayed during the harvest season in September and October, the damaged by bugs did not decreased, and further research is needed.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.903-915
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• 2011

Recently, anaerobic methane production of agricultural waste biomass has received increasing attention. Until now domestic BMP (Biochemical methane potential) studies concerned with agricultural waste biomass have concentrated on the several waste biomass such as livestock manure, food waste, and sewage sludge from WWTP (Waste water treatment plant). Especially, the lack of standardization study of BMP assay method has caused the confused comprehension and interpretation in the comparison of BMP results from various researchers. Germany and USA had established the standard methods, VDI 4630 and ASTM E2170-01, for the analysis of BMP and anaerobic organic degradation, respectively. In this review, BMP was defined in the aspect of organic material represented as COD (Chemical oxygen demand) and VS (Volatile solid), and the influence of several parameters on the methane potential of the feedstock was presented. In the investigation of domestic BMP case studies, BMP results of 18 biomass species generating from agriculture and agro-industry were presented. And BMP results of crop species reported from foreign case studies were presented according to the classification system of crops such as food crop, vegetables, oil seed and specialty crop, orchards, and fodder and energy crop. This review emphasizes the urgent need for characterizing the innumerable kind of biomass by their capability on methane production.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.273-282
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• 2023

Hypochaeris radicata, native to Europe and Eurasia, is a perennial plant of the Asteraceae family. In Korea, H. radicata was reported in 1992, mainly in Jeju Island, and gradually spreading to the inland. It overwinters in the form of a rosette and blooms yellow flowers from May to June. H. radicata propagates by seeds and rhizomes. The germination temperature of the seed is 15/20℃ (day/night), and the rhizome forms a new plant at a depth of 2-3cm in the soil. The roots of H. radicata secrete allelochemicals that inhibit the development of other plants. Some use it as a salad or forage substitute but to a limited extent. However, extensive research on ampicillin contained in H. radicata has been conducted, and its anticancer and anti-inflammatory effects have been recognized. There are only a few methods to manage H. radicata both culturally and physically. In orchards, soil treatments such as oxyfluorfen and diclobenil, or nonselective foliar treatments such as glufosinate-ammonium and glyphosate are used. Notably, there are no known biological control agents.

• Research in Plant Disease
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• v.29 no.3
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• pp.276-285
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• 2023

This work investigated the viral infection in jujube plants in Korea. A total of 61 samples with the symptoms of putative viral infection were collected from experimental fields and orchards. Thereafter, the samples were subjected to metatranscriptome analysis, Reverse transcription polymerase chain reaction analysis, and nucleotide sequence analysis. These analyses identified the presence of two DNA viruses, jujube-associated badnavirus (JuBV), jujube mosaic-associated virus (JuMaV), and one RNA virus, jujube yellow mottle-associated virus (JYMaV). All samples collected were confirmed to be infected by at least one of the three viruses, with most showed multiple infections. The detection rates of JuBV, JYMaV, and JuMaV were 100%, 90.2%, and 8.2%, respectively. Only three combinations of viral infections were found: 9.8% of samples showed single infection of JuBV, 82.0% showed double infection of JuBV+JYMaV, and 8.2% showed triple infection of JuBV+JYMaV+JuMaV. Sequence analysis of the three viruses showed very high homology with respective virus isolates reported in China. This study is predicted to provide fundamental data to produce virus-free jujube seedlings and represents the first report of JuBV and JuMaV infection in Korea.