• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.270-274
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• 1997

This experiment was conducted to evaluate the combining ability of japonica rices for improving the salinity tolerance at seedling stage. Nine varieties used in partial diallel analysis included three varieties of each tolerant, moderately tolerant and susceptible one. Twelve-day-old seedlings were grown in saline solution, initially at an EC of 6 dS /m for four days, followed by an EC of 12 dS /m for 20 days. The agronomic characters at seedling stage such as plant height, dry shoot weight and dry root weight were measured to analyze for combining ability of the parents. General combining ability(GCA) and specific combining ability(SCA) effects were highly significant for all tested parameters. However, mean squares for GCA were about five times larger than that for SCA suggesting the preponderance of additive gene action. Among tolerant varieties, Gaori and Namyang 7 were good combiner for improving the salinity tolerance at seedling stage in GCA as well as SCA.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.256-264
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• 2021

Rapeseed (Brassica napus L.) is generally sown in late autumn and harvested in early summer in Korea, however, spring cultivation has also been attempted in some areas because frequent climate changes induce reducing productivity. Therefore, there is a need for a transplanting technology that is relatively easy to control of cropping season according to changes in cultivation conditions. In this study, to find out the optimal characteristics of seedlings for machine transplanting of spring cultivation, seedling morphological characteristics were investigated according to the seedling age of three varieties for 2020 and 2021. The hypocotyl length was less than 2 cm in both years and the 40-day-old seedling was the shortest among all seedling ages. The number and size of leaf were increased with longer seedling age in both years. To evaluate seedling quality, total seedling length, seedling weight, and impact resistance were measured before transplanting. Total seedling length was the longest in 40-day-old seedlings and the shortest in 25-day-old seedlings in both years. In the case of seedling weight, no significant differences were observed depending on the seedling age and the impact resistance increased with increasing seedling age. Finally, 'Jungmo7001', 'Naehan', and 'Tamla' showed a high transplanting rate in seedlings grown for more than 30 days, 35 days, and 40 days, respectively, in the field using a general transplanter. These results suggest that the proper seedling age for transplanting is limited depending on the rapeseed varieties. The suitable seedling cultivation method can be selected for different cultivation environments.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.121-130
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• 1995

Greenhouse and laboratory studies were conducted to investigate allelopathic potential of some weed species on alfalfa(Medicago sativa L.) germination and seedling growth. In the comparison between top(leaves+stems) and root extracts, top extract exhibited greater allelopathic effects on alfalfa germination than that of root. The various weed species extract differently responded to alfalfa test species, WL-320, in terms of allelopathic effect. Top and root aqueous extracts of lambsquarter(Chenopodium album L.), giant foxtail(Setaria faberii Herrm.), redroot pigweed (Amaranthus retroflexus L.), velvetleaf(Abutilon theophrasti Medic.), crabgrass(Digitaria sanguinalis L.), canada thistle(Cirsium arvense L.) and prostrate knotweed(Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, vigor, and rate of germination of alfalfa. The regression slopes of various top extracts showed that velvetleaf(b=3.69) extracts were the most inhibitory, while large crabgrass(b=2.39) extracts had the least allelopathic effect on alfalfa germination. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Also, more of the toxic effects were observed from the dried extracts compared to the fresh extracts. Residue of velvetleaf inhibited significantly alfalfa emergence and survival percentage compared to the control. The emergence and survival percentage of alfalfa were 44%, 57% at 1.0% residue treatment, respectively. When weed residues were mixed with silica sand with incubation time, velvetleaf residue most inhibited alfalfa growth. The degree of inhibition increased as incubation time increased. An incubation for 72h caused the greatest inhibition of alfalfa growth. These results demonstrate the different allelopathic activity of weed species extracts on alfalfa and suggest that weed may affect alfalfa growth and development through the inhibitory effects of allelochemicals present in weed tissue.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.839-844
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• 2015

This study was carried out to investigate seedling quality, growth characteristics and yield of hot pepper (Capsicum annum) grown in the open field according to seedling growth periods (SGPs) of 45, 55, 65, 75, and 85 days. Before planting, plant height, node number, leaf area, fresh and dry weight of seedlings were high in longer-SGP treatments, the T/R ratio was high in SGP 45 and SGP 85 treatments compared with other treatments. At 10 weeks after planting, plant height, stem diameter and leaf area of plants treated with SGP 45 and SGP 55 were significantly higher compared to other treatments. Fresh and dry weight of the plant with SGP 45 treatment was greatest, however, the dry matter percentage with SGP 45 was low compared to other treatments. Fruiting number and weight per plant were highest in SGP 45 treatment. Shorter SGP treatments such as 45 and 55 days gave greatly increased total weight of ripened fruit at 18 weeks after planting. Our results showed that SGP for hot pepper grown in the open field influences plant growth parameters and marketable yield, so that SGP 45 to SGP 55 is optimum to cultivate hot pepper plant.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.1
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• pp.6-11
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• 1991

In order to classify the varieties by the characters to evaluating potential winter hardiness was examined using the relationships between autumn growth of seedling plants and the dry weight of plant(DW), and yield components of 1st cutting in 16 varieties of perennial ryegrass grown under individual plant basis.The results are summarized as tollows:1. The dry weight of plant(L)W) was positively correlated with the number of tillers of seedling plants, but negatively correlated with seedling vigors of plants in autumn growth. 2. The dry weight of plant(L)W) indicated positively significant correlations with the dry weight of heading tillers(HDW), number of tillers per plant(NT), number of vegetative tillers(VNT), number of heading tillers(HNT), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.3. Relative tiller appearance rates(RTAK) corresponded with the seasonal patterns of tillering ability. Thevariety with a low values of relative tiller appearance rates(RTAR) showed vigorous tillering ability inautumn growth, but the variety with a high values of relative tiller appearance rates(KTAR) showedvigorous tillering ability in spring growth.4. The dry weight of plant per relative tiller appearance rates(DW/RTAR) indicated positively significant correlations with the dry weight of plant(DU7, plant length(PL), dry weight of heading tillers(HDW), number of tillers per plant(NT), number of heading tillers(HNrr), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.5. The varieties were classified into 2 groups by the dry weight of plant per relative tiller appearance rates(DW/RTAR). Thus. Manhattan, P-2, Tonga, Tove, Hella. I'eramo and Fiesta belong to the group of DW/RTAII>l. 0, and Maprima, Caliente, Tempo, Gambit, Magella, Prana. Reveille, Barlet and Bravo belong to the group of DW/RTAR

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.156-161
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• 2006

Overhead and sub-irrigation of deep sea water to tomato seedlings reduced the height as 50% and 58% than control plants. In the same treatment with surface sea water and NaCl water, the reduced rate in tomato seedlings' height were 49% and 56% in overhead irrigation, and 47% and 57% in sub-irrigation, respectively. Most effective method for the inhibition of the growth of the seedling was sub-irrigation method, which supplied water through the roots. No significant difference was observed on fresh weight of the upper part of tomato and cucumber seedlings, though the sub-irrigation reduced the fresh weight than the overhead irrigation. The reduced rate of fresh weight of seedlings by overhead irrigation was by 38% and sub-irrigation by 49% as compared to control. Similarly dry weight of upper and under soil parts of seedlings showed same trend of results thereof as fresh weight. This result can be traced to reduction of growth caused by salts in the water. In stem diameter of seedlings no significant difference was observed between two irrigation methods, even though both deep sea and NaCl water reduced stem diameter, as compared to control water. Overhead irrigation can be chosen by seedling producers because of better seedling quality by using TH ratio. Seedling compactness were not noticed in both the overhead and sub-irrigation. Sub-irrigation was found more effective method far the inhibition of height and compactness of tomato seedlings. Higher the concentration of NaCl, deep sea, and surface sea water, lesser the growth in height, fresh and dry weight, stem diameter, and leaf area was obtained. No significant difference was found, though sub-irrigation suppress the growth of seedlings.

• Journal of Ginseng Research
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• v.8 no.1
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• pp.65-74
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• 1984

This experiment was carried out to study the effects of light intensity and soil water regimes on the growth of ginseng seedling. The results were as follows: 1. The maximum light intensity and optimum temperature in 1,le photosynthesis of ginseng seedling were 10,000 lux and 23 $^{\circ}C$. Respiration rate was increased at high temperature. 2. Air and soil temperature under the shading were increased as the increase of light intensity but soil water contents were decreased as the increase of light intensity, whereas air and soil temperature were decreased as the increase of precipitation under the shade b5: soil water contents were increased as the increase of precipitation under the shade. 3. The higher the transmittance of the shade, the greater the specific leaf weight (S.L.W.) and stomatal density. In contrast, however, the contents of total chlorophyll, chlorophyll a and b, and stomatal length was decreased. There was no any significant difference light intensity of the a/b ratio of chlorophyll. 4. The highest photosynthesis was occurred in ginseng leaves grown under the shade 5% L.T.R. and net photosynthesis rates increased with increasing soil water contents. 5. Optimum condition for usable seedling yield were 5% L.T.R. and 3.3% precipitation under the shade. Useless seedling increased with increasing precipitation under the shade.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.2
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• pp.102-106
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• 1997

The inluence of styrofoam-panel thickness of floating frame on the seedling growth of flue-cured tobacco(Nicotiana tabacum L.) in the newly developed direct-seed float system was investigated . Floating frame used instead of styrofoam-tray consisted of styrofoam-panel (106×108cm) for floating, eight holes(1.Sx2S.0 cm) to uniform the water, and nutrition supply far seedling and water and nutrition absorption cloth placed on the styrofoam-panel. Each floating-frame may lay eight plastic-trays on it. Eight grades of styrofoam-panel thickness from 26 mm to 46mm and two kinds of media were used in the greenhouse system. Dry cells were found from the styrofoam-panel thickness of 43mm in carbonized chaff, compost and original soil rate of L3-3(v/v) media, and of 37mm in peat and perlite rate of 8-2(v/v) media. The thinner styrofoam-panel produced more tender and succulent seedling with the more trunk and the less root weight. When considering the appearance of dry cell, seedling growth, producing healthy tobacco seedlings, and utilization of styrofoam-panel for two kinds of medias the ideal styrofoam-panel thickness were suggested to be around 34mm for flue-cured tobacco reeling production in the newly developed direct-seeding float system. Key words : tobacco seedlings, float system, medium, styrofoam pannel, dry cell.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.73-78
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• 2012

$Calotropis$ $procera$ L. is a perennial shrub distributed in saline areas of deserts of South Asia. Salt stress is a very challenging subject in arid and semi-arid areas. Germination stage is very sensitive and many plants do not germinate in saline soil. The objective of this study was identifying the salinity effect on seed germination of $Calotropis$ $procera$ L. The experimental design was a complete randomized block design with NaCl and $CaCl_2$ at five levels of isobar concentrations: 0.0, -0.01, -0.05, -0.1, and -0.15 MPa. Osmotic potential had significant effects ($P$ < 0.01) on germination percentage, germination rate, shoot length, root length, and seedling dry weight. All seedling characteristics decreased with decrease in osmotic potential. Shoot length and root length decreased more than the seedling characteristics. Germination was completely inhibited in -0.1 Mpa. Priming with NaCl and $CaCl_2$ (-0.1 MPa) for four days had significant effects ($P$ < 0.01) on the germination percentages. Priming improved the seedling characteristics in all samples, especially in -0.05 Mpa, but a decrease with decrease in osmotic potential.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.77-86
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• 2019

To determine none top soil covering in rice seedling nursery method for the sparse machine transplanting, four different sowing methods were tested. Shoot and root length, fresh weight, leaf number and color using leaf color chart(LCC) and SPAD were collected as the data comparison of methods. The seedling height showed the highest growth according to the conventional (230g seed rate of pre-emerged seeds and top-soil covering) > high sowing density 1 (290g seed rate of pre-emerged seeds and top-soil covering) ≥ high sowing density 2(290g seed rate of pre-emerged seeds and none top-soil covering) > high sowing density 3(290g seed rate of iron-coated seeds and none top-soil covering). There was any statistical difference between groups in root length, leaf number, LCC, and SPAD values. Thus, a high sowing density of 290g for rice nursery seedling box was recommended to the sparse machine transplanting in rice cultivation with the none top-soil covering method, enabling convenient handling in transportation and machine transplanting work.