• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.424-430
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• 1990

The variation of needle, cone and seed characteristics and of allelic frequency in isoenzyme, ADH, ME and PGI, according to different resin duct index in Pinus densiflora, Pinus thunbergii and their hybrids was analyzed. The results obtained were as follows : 1. With increase of number of resin ducts, morphological characteristics such as needle length, needle sheath length, cone size, seed size, seed wing size, 1000 seeds weight, etc. tended to he increased, while number of stomata row in needle to be decreased. 2. As the results of discriminant analysis for the morphological characteristics of needle, cone and seed, most individuals are generally coincided with number of resin duct mostly in Pinus densiflora were not. 3. According to the canonical discriminant function obtained from the morphological characteristics in Pinus densiflora, Pinus thunbergii and their hybrids including introgressive hybrid, the resin duct index, 1000 seeds weight, cone size and neelde sheath length characterized fairly their species. 4. With increase of resin duct index, hybrid index tended to be higher. The results obtained from the discriminant analysis and the hybrid index were nearly same each other. 5. With increase of number of resin duct, the allelic frequencies for isoenzyme, ADH-$B_2$, ME-$A_2$ and PGI-$B_1$. $B_2$ tended to increase but those of ADH-$B_3$, ME-$A_4$, and PGI-$B_3$, to decrease. It is thought that this increase of frequency for the former four isoenzymes was resulted in introgressive gene flow from Pinus thunbergii to Pines densiflora and accordingly the frequency of latter three isoenzymes tended to decrease.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.89-97
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• 2020

This experiment was conducted at Sancheong from 2013 to 2015. The objective of this study was to establish the seeding rate, and to clarify the optimum nitrogen fertilizer level for rye seed production in the southern area of Korea. We employed Korean rye cultivar 'Gogu' in this test. The experimental design was a split-plot design with three replications. A split-plot design was used with three seeding levels (3, 5, and 7 kg 10 a^-1) on the main plots and other treatments fully randomized in sub-plots. A factorial arrangement of treatments included three different nitrogen fertilizer levels (0, 3, 6, and 9 kg 10 a^-1). The grain yields of rye affected by increasing the seeding rate. The number of spike per m² and immature grain weight was increasing, while the fertility rate and the number of grain per spike were decreased as seeding rate were increased from 3 kg 10 a^-1 to 7 kg 10 a^-1. The percentage of a productive tiller, 1-liter weight, and 1000-grain weight also decrease by increasing seeding but the grain yields of rye had less effect. There was an increase in the number of spike per m², the number of grain per spike, and grain yields as nitrogen fertilizer level was increased from 0 kg 10 a^-1 to 9 kg 10 a^-1 and followed a delaying heading and an increasing lodging of the plant. But grain yields did not affected by the interaction of seeding rate × nitrogen fertilizer levels. The best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and 3 kg 10 a^-1, respectively, considering seed and fertilizer reduction and the prevention of pollution by excess fertilization.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.237-244
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• 2018

This study was carried out in order to secure basic data of seedling mass propagation technique of Rhododendron mucronulatum which is the native tree species of Korea by surveying the characteristics of its fruit and seed. The fruits were collected at Mt. Goryeo in Ganghwa-gun on different dates in 2013; August 26th, September 5th, September 12th, October 4th. The seed germination test was carried out at 5, 10, 15, 20, 25 and $30^{\circ}C$. Moisture content of the fruit was highest (54.5%) in the fruit collected on September 5th. Number of the seeds in a fruit was 91.3 to 116.3, regardless of the collection date. Seed length was highest ($1947.4{\mu}m$) in the seeds collected on October 4th and seed width was highest ($727.3{\mu}m$) in the seeds collected on September 12th. Germination rate of the seeds was highest at $25^{\circ}C$ regardless of the seed collection date, which showed the highest value(27.3%) in the seeds collected September 12th. Meanwhile, the seeds were not germinated not at all at 5, 10 and $30^{\circ}C$. $T_{50}$ and mean germination time of the seeds got shorter at the higher temperature. Germination uniformity got lower when the collection date got later. Germination speed of the seeds was fastest at $25^{\circ}C$. According to the results of this study, it seems that the appropriate time to collect fruit and seed is between September 12th and October 4th, and the appropriate temperature for the seed germination is $25^{\circ}C$.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.62-66
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• 2007

This study was carried out to develop the stable plug seedling production for hydroponics of spinaches by various nursery media, plug tray size and seed number per plug tray cell. When plant grown in various nursery media, the seeding stand rate was shown in order of granular rockwool with good water retention, granular rockwool>granular rockwool mixed with pearlite>cocopeat>pearlite>poly urethane foame. Thus, poly urethane foame indicated the lower seedling stand rate. There was no difference in growth of the seedlings md the seeding stand rate by the plug tray size, and no significant difference in the plant height and the number of leaves among the seed number per plug tray cell. But, leaf area of plant in 2 grains seeding per cell was $113.0cm^2$, was wider in compared with 5 grains seeding of which leaf area was $88.0cm^2$. Accordingly, the leaf area per plant decreased as more and more the number of seeds per plug tray cell increased. The fresh weight of a plant per plug tray cell was the heaviest with 12.5g in the 2 grains, and the total fresh weight of plants per cell was 33.9g in 4 grains seeding, thus it tended to was bigger compared with other treatments. Consequently, given that the number of seeds per cell was decreased, the fresh weight of a plant increased. On the other hand, the total fresh weight per cell showed a tendency to be reducing as more and more the number of seeds per plug tray cell decreased. The yield in the 4 grains seeding was increased by 46% as $14,910kg{\cdot}ha^{-1}$ in compared with the yield in 2 grains seeding as $10,200kg{\cdot}ha^{-1}$.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.1-5
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• 2012

A simple monitoring method was designed to evaluate seed bank in a upper soil (0 to 30 cm depth), which was observed for the pattern of vertical distribution of weed in the soil under tillage or no-tillage condition. The field experiment was established at an organic corn field located in Hwacheon in Kangwon-do from 2010 to 2011. Undistributed linear soil samples were taken using non-destructive soil sampler from 0 to 30 cm depth at the tillage or no-tillage soils. Weed seed distribution in the linear soil samples was estimated by counting the number of weed germinated according to the soil depth. Under tillage condition, the weed seeds were more evenly distributed from 0 to 30 cm depth, with being 75% of weed seeds located in 0 to 15 cm depth compared to the no-tillage condition. Soil samples taken by no-tillage condition had 85% of weed seeds within 15 cm of soil depth, with being 93% of weed seeds from 0 to 20 cm depth. The number of weeds or the number of weed species were three times higher for tillage soil compared to no-tillage soil, and the major dominant weed species were observed for annual plants, such as Echinochloa crus-gall, Mollugo pentaphylla, and Digitaria ciliaris.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.57-64
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• 1991

This experiment was conducted to elucidate the effect of plant growth regulators (PGR) on the root -mat formation of infant seedling (8- to 10-day-old seedling) of rice in machine transplanting. The rice seeds of Odaebyeo were socked in water with different concentrations of PGRs for 48 hours at room temperature. Seeding rate was 220 g per seed tray (30x60x3cm). Metalaxyl (25% wettable powder) was used for a fungicide. Generally, the metalaxyl-treated seeds markedly promoted the root growth of the rice seedling, while tetracy-cle, pachlobutrazol and NTN -821 reduced the seedling height and root length, and thickened the shoot diameter at higher concentation levels. Tetracycle decreased root length of the rice seedlings but increased root number per seedling, and root-mat formation was poor. Whereas, metalaxyl concentrations of 200 and 1,000 ppm markedly increased root length and number of root hairs without decreasing root number, thus root-mat formation was excellent. The optimum concentration of metalaxyl seed treatment to increase the root-mat formation of infant seedling of rice was about 200 ppm. Metalaxyl seed treatment could be advanced one to two days of the duration of root-mat formation compared with control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.351-358
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• 1995

Since summer growth depression of forage crops limits hay production in Korea, it is important to exploit natural resources which are suitable as forage. In the preliminary experiment it was found that Panicum dichotomiflorum Michx. might be utilized as soiling and hay crop. Effects of seed stratificaion, planting date and number of harvestings on fresh and dry yields of Panicum dichotomiflorum Michx. were investigated in 1993 and 1994. Stratification of seed promoted emergence, while seed age decreased emergence. Although fresh yield was closely related with number of plants estabilished per unit area, effect of number of plants per unit area on yield was less at the later stage of growth. Higher cutting height decreased fresh and dry yield at th early stage, but final yields were not influenced by cutting height. Panicum dichotomiflorum Michx. could be harvested 3~4 times beginning 40~50 days after planting and fresh and dry yields were 9~10 tons /10a and 1.4~1.8 tons /10a, respectively. Fresh and dry yields were significantly influenced by growth duration or accumulated temperature between cuttings. Leaf blade ratio was higher at earlier planting and / or harvesting. Contens of crude protein, crude fat and crude ash were 16.32, 24.01 and 11.59%, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.102-102
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• 2022

More than 74% of forage crops in Korea are cultivated in winter rice fields. Italian ryegrass (IRG) can be said to be a representative forage crop, but over 70% of its seeds are dependent on imports. In addition, there are concerns that the stable supply of research fees may be disrupted due to the effects of climate change, war, and other factors. Therefore, it is necessary to secure a large production area for stable supply. Korea's reclaimed land area is 135,000 ha and its agricultural area is 112,000 ha. Therefore, this study attempted to apply IRG to the domestic IRG seed industry through stable cultivation techniques on reclaimed land. In this study, IRG 'Kowiearly' varsity was cultivated in late October 2020 and early October 2021 in the Saemangeum reclaimed land. The seeding methods were conventional drill sowing seeding, new technology spot seedling (30 × 18 cm) and new technology drill sowing seeding. The amount of sowing was conventional drill sowing seeding 2.0(kg/10a), new technology spot seedling 1.5(kg/10a), and new technology drill sowing seeding 1.5(kg/10a). Fertilizer application amount is conventional drill sowing seeding(N-P₂O₅-K₂O) 9.0-12-12(kg/10a), and new technology spot seedling and drill sowing seeding were(N-P₂O₅-K₂O) 4.5-12-12(kg/10a) respectively. Fertilizer was applied accordingly. After that, in February, the conventional drill sowing seeding, new technology drill sowing seeding and spot seedling applied 4.0 and 2.2(kg/10a) of nitrogen supplement fertilizer, respectively. Before wintering, plant length was higher in 2022 than in 2021, but leaf number was higher in 2021. Heading time was April 30, 2021 and April 25, 2022. In heading time, plant length was 74 cm in 2021 and 67 cm in 2022, lower than in 2021. On the other hand, There was no difference in the number of panicle and the number of seeds in the 2021 harvester in all treatment plots, and, thus seed yield was no differ. However, the drill sowing seeding and spot seedling of the new technology were somewhat higher than the conventional drill sowing seeding. On the other hand, seed yield was decreased in all treatment plots compared to 2022 because of raifall deficiency in 2021.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.251-255
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• 2008

This study was carried out in 2002 to determine the usefulness of Jeju scoria for a component of a growth medium and optimum planting density of 'Dejima' seed potatoes (Solanum tuberosum L.) grown in a wick hydroponic system. The minitubers ($7.0{\pm}0.2\;g$) produced in an aeroponics system were planted at five planting densities (3 to 15 tubers/box; 19 to $95\;tubers/m^2$) in polystyrene boxes (51 cm long $\times$ 31 cm wide $\times$ 20 cm high) containing two media (perlite + peatmoss and Jeju scoria + peatmoss 1:2, v/v mixtures). There were no significant interactions between medium and planting density for the growth and tuber yield traits. Shoot growth and the number of tubers per plant were not significantly affected by the media. However, tuber yield was higher in the perlite + peatmoss mixture than in the Jeju scoria + peatmoss mixture. The percentage of underdeveloped plants ranged from 8.3 to 14.7% at four lower planting densities (3 to 12 tubers/ box), and was 25.8% at the highest planting density (15 tubers/box). As planting density was increased from 3 to 15 tubers per box, seed potato (${\geq}5\;g$ tuber) number increased from 101 to 269 and yield from 6.3 to $11.6\;kg/m^2$. These results indicate that the perlite + peatmoss mixture might be more suitable for seed potato production in the wick hydroponic system, and considering the percentage of underdeveloped plants and tuber yield, optimum planting density would be 56 to $76\;tubers/m^2$ in the system depending on availability of seed potatoes.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.578-587
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• 2015

Nuclear SSR (nSSR) and chloroplast SSR (cpSSR) markers were analyzed to assess the parameters of mating system in seed orchard, such as outcrossing rates, the number of potential pollen contributors, paternal contribution rates, degree of pollen contamination, and biparental inbreeding ($t_m-t_s$). In 2006, 2007, seeds were collected from the seed orchard of Pinus densiflora, established in 1977 at Anmyeon island. Estimates of outcrossing rates ranged from 94.9 to 100% (mean 98.9%) in 2006 and from 91.2 to 100% (mean 97.7%) in 2007 on the basis of the analysis of cpSSR haplotypes and from 90.3 to 100% (mean 95.9%) in 2006 and from 81.6 to 100% (mean 95.3%) in 2007 on the basis of the analysis of nSSR genotypes. By cross checking of both DNA markers, mean cumulative outcrossing rates of 100% and 98.9% were estimated in each year. Mean contamination rates were estimated as 48.9% and 42.4%, respectively. On the basis of cpSSR haplotype observed in each seed, paternal contribution rates (the number of pollen contributors) were estimated as 0.458 (mean 16.2) in 2006 and 0.512 (mean 14.8) in 2007. In conclusion, considering pretty high level of outcrossing rates observed in a seed orchard, there might be little to be influenced by inbreeding depression for genetic potential of the seeds induced by selfing. Estimates of the mating system parameters obtained from the two reproductive years were not statistically different, which revealed stable genetic quality of seeds produced in different years. Observed results from this study may provide useful information for the management and establishment of the seed orchard of the progressive generation.