• Korean Journal of Organic Agriculture
• /
• v.14 no.4
• /
• pp.411-420
• /
• 2006

Indole-3-acetic acid (IAA) biosynthesis by bacteria occurs widely in rhizospheres. Bacterial species able to synthesize IAAmay be exploited for beneficial interactions in crop management systems. The objective of this study was to determine the response of ivyleaf morningglory (Ipomoea hederacea) seedlings to IAA and to an IAA-producing rhizobacterum, Bradyrhizobium japonicum isolate GD3. IAA solution and isolate GD3 suppression of seedling growth measured as radicle length and biomass depended on IAA concentration. Seedling radicle length was significantly reduced by ca. 29% with more than $1.0{\mu}M$ of IAA solution, compared to the control, 48 h after application. The cell concentration at 50% growth reduction ($GR_{50}$) of the seedling radicle was IAA production by isolate GD3 at $10^{4.82}\;cfu$, the cell concentration for 50% growth reduction ($GR_{50}$) of seedling radicle was 0.24 iM, which was much lower than the IAA solution concentration ($117.48{\mu}M$) required for $GR_{50}$. Therefore, excess IAA production by isolate GD3 may be more detrimental to morningglory radicle growth than standard IAA solution. Results confirmed involvement of IAA in suppressive effects of isolate GD3 on morning-glory seedlings grown in a hydroponic system.

• Korean Journal of Medicinal Crop Science
• /
• v.11 no.5
• /
• pp.340-346
• /
• 2003

This study was carried out to improve cultivation techniques by low cost and labour saving in ginseng (Panax ginseng C. A. Meyer) seedling production, by elucidating proper ratio virgin soil and organic fertilizer, suitable height of front piller. The obtained results are as follows ; The optimal ratio of white decomposition of virgin soil and organic fertilizer was 10:1 for good yield of standard seedling, The fittest height of front piller was 150 cm because of both good seedling growth and yield. The cost for production of seedling of ginseng could be reduced by both optimal ratio of virgin soil, organic fertilizer and selection of front piller height.

• Korean Journal of Plant Resources
• /
• v.25 no.5
• /
• pp.586-590
• /
• 2012

This study was conducted to investigate the seedling cultivation methods of Ostericum praeteritum Kitag. The results are as follows ; Ostericum praeteritum transplanted from wild seedlings and seedling cultured in the open field grew quite well, but their bolting rate was higher than other seedlings resulting in low root production. Seedling cultured in tray pot of green house produced good quality root as 426 kg/10a indicating the most adequate seedling method for Ostericum praeteritum production. Main compounds of Ostericum praeteritum roots were found as oxypeucedanin and bisabolangelone, and contents of wild seedlings were lower than theirs of the other seedlings methods.

• Journal of Korean Society of Forest Science
• /
• v.101 no.2
• /
• pp.317-323
• /
• 2012

This study was performed in order to explore the growth characteristics by growing stage in the containerized seedling and the bare root seedling of Chamaecyparis obtusa Sieb. et Zucc., which is the major plantation species of Korean southland. The height growth of 1-year-old bare root seedlings was better than containerized seedlings, which grew in the containers with capacity of 31.2 mL and 300 mL. The root collar diameter growth was the best in the containerized seedlings of container with 300 mL. The 2-year-old bare root seedlings were surveyed to be better in the height and root collar diameter growth than the containerized seedlings of container with 300 mL. In the comparison of dry mass production, it was the highest in 32 mL containerized seedlings as for 1-year-old above ground and in 300 mL containerized seedlings as for below-ground and total dry mass production. In case of 2-year-old seedlings, it was indicated to be high in bare root seedling as for the part above ground and in dry mass production of the containerized seedling as for the part below ground. In the comparison on root morphological traits of seedlings such as the total root length, the root project area, the root surface area, the average diameter in root, and the root volume, all of 1 and 2-year -old containerized seedlings showed the higher growth than the bare root seedlings except the average diameter in root. Synthesizing the results of this experiment, the containerized seedlings are relatively excellent in root development compared to bare root seedlings in the process of producing seedlings of C. obtusa, thereby being judged to have grown into excellent seedlings.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.52 no.2
• /
• pp.134-139
• /
• 2007

The research was conducted with the aim of determining effects of seedling age on the yield of four fine rice varieties viz., Kalizura, Tulshimala, BRRI (Bang-ladesh Rice Research Institute)-37 and BRRI-38. The seedling of different ages such as 15, 25, 35 and 45 days were transplanted on the same day maintaining $25cm{\times}15cm$ spacing. The experiment was laid out in a randomized complete block design with three replications. The yield and yield contributing characters were influenced by seedling age, variety and their interaction. BRRI-38 gave the highest number of effective tillers $hill^{-1}$, panicle length, total spikelets $panicle^{-1}$, grains $panicle^{-1}$, 1000-grains weight and grain yield. Likewise, yield and yield contributing characters were the highest in 35 days old seedling. On the other hand, the variety (BRRI-38) with the same age as of seedlings 35 days old seedlings was found superior to other interactions, but, in the production of grains $panicle^{-1}$ and 1000-grains weight there was no significant effect in this interaction. From the findings it may be inferred that BRRI-38 with 35 days old seedlings produced the highest grain yield.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.4
• /
• pp.284-288
• /
• 2001

Water deficit is a serious constraint to soybean [Glycine max L. (Merr.)] production in rainfed regions of Asia, Africa, and America. This study was conducted to develop a simple and effective screening method for drought tolerance in soybean. Fifteen soybean cultivars, eight identified to be drought-tolerant and seven drought-sensitive in previous studies, were used for the evaluation of drought tolerance under the new screening conditions. The seedling screening method was consisted of a treatment in a PEG solution and drought treatment in parafilm-layered pots. 5-day-old seedlings were treated in a 18% PEG solution for 4 days and their wilting and hypocotyl browning were recorded. Three seedlings grown in a parafilm-layered pot containing peat moss were drought-stressed by withholding water from the third day after seedling emergence, and root and seedling growth were examined. Degree of drought tolerance were rated based on seedling vigor in the PEG solution and drought-stressed parafilm-layered pots, and also on the penetration ability of roots through parafilm layer. Most of seedlings of the drought-tolerant cultivars showed higher vigour and root penetration than those of the drought-sensitive cultivars under the new screening conditions. Our results indicate that the new method can be used as a simple and effective screening procedure for drought tolerance in soybean breeding programs.

• Journal of Bio-Environment Control
• /
• v.25 no.4
• /
• pp.302-307
• /
• 2016

The aim of this study was to examine the optimum wattage and installation height using nano-carbon fiber infrared heating lamp (NCFIHL) for heating energy saving and plug seedling production in plug seedling production greenhouse in winter season. NCFIHL of 700 and 900 W was installed over the bed ($1.2{\times}2.4m$) as 0.7, 1.0, and 1.3 m height, respectively, for the production of grafted watermelon seedling in venlo-type glasshouse. Watermelon (Citrullus lanatus (Thunb.) Manst.) 'Jijonggul' and gourd (Lagenaria leucantha Rusby.) 'Sunbongjang' were used as scions and rootstocks, respectively. The scions and rootstocks were grafted by single cotyledon ordinary splice grafting. Light intensity of NCFIHL was below the $1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in all treatment. Spectral distributions of NCFIHL presented mostly infrared area. When outside air temperature was below $10^{\circ}C$, 700 and 900 W NCFIHL installed with 0.7 m height treatment and 900 W NCFIHL installed with 1.0 m height treatment maintained the setting air temperature ($20^{\circ}C$) at night. In the result of taking thermal imaging, the grafted watermelons were getting warm fast in 900 W NCFIHL installed with 0.7 m height treatment at night. Compactness of the grafted watermelons was the greatest in 700 W NCFIHL installed with 1.3 m height treatment. The results indicate that NCFIHL installed above 1.0 m height using 700 W was suitable for production of plug seedling.

• Korean Journal of Plant Resources
• /
• v.11 no.3
• /
• pp.290-295
• /
• 1998

Presowing treatements to seed are reasonable for elevating the seedling production efficiency. This experiment was carried out to determine the effects of $GA_3$ [0 (water) : 0.01 mM] and light qulaity (red : white) simultaneously treated before sowing on seedling emergence and growth of tobacco (Nicotiana tabacum L.) cv NC 82 and Burley 21. Red or white light was illuminated 12 hours a day while seeds of the cultivars were imbibed with either water or $GA_3$ 0.01 mM for 3 days. Seedling emergence was measured up to 20 days after sowing but morphological characters and dry weights were done 40 days. The seedling emergence rate of cv NC 82 was more affected by light quality and $GA_3$ pretreatments than that of cv Burley 21. Light quality more influenced the rate than $GA_3$ while red light or water imbibition enhanced the rates of the two cultivars compared to the other treatement. Although mean plant height and leaf number per seedling were nearly equal between the treatements, red light declined leaf area per seedling of cv Burley 21 of which seeds were imbibed in water but white light decreased the areas of both cultiars of which seeds were soaked in $GA_3$solution. Shoot dry weight was greater in cv NC 82 but less in cv Burley 21 pretreated with red light, and root dry weight showed the reverse result in white light, meaning that presowing light and $GA_3$ treatments could be changed the seedling development and growth of tobacco.

• The Korean Journal of Ecology
• /
• v.9 no.1
• /
• pp.73-78
• /
• 1986

The effects of density and soil nutrient regime on competition between individuals in pure and mixed populations of two annuals. Chenopodium album and Digitaria sanguinalis were investigated at the level of enegy allocation. Seedling emergence of two species was extremely high (>90%) in both pure and mixed culture irrespective of the density and nutrient regime, but percentage of seedling establishment or fertile plant became gradually low with increasing density owing to 'self-thinning'. The mean plant dry weight was significantly reduced with increasing density and decreasing soil fertility. The dry matter production of D. sanguinalis in mixture was markedly greater than in pure culture under medium and high density. Also, as considered the number of seed production as reproductive allocation, relationship between them and the number of seed production per plant showed a similar tendency. Therefore, these results indicated that D. sanguinalis had a greater competitive advantage than C. album and energy allocations to variious organs were regulated by plastic response rather than determined genetically.

• Korean Journal of Organic Agriculture
• /
• v.19 no.spc
• /
• pp.135-138
• /
• 2011

In traditional organic rice culture practices, control of weeds is a big problem. This study was conducted to increase the rice production. Results showed that Plant height, SPAD, root length and weight were higher in pot raised seedling than broadcasting method except number of panicles. High plant density caused reduction in plant height, number of culm and chlorophyll content of the rice. No lodging was observed in both methods. Thickness of third internode and culm length was more in pot raised seedlings at both sites. When organic material was used rice yield increased by 3.81%. Higher rice production (10%) was recorded in the fields planted with pot raised seedlings. From the above study it could be conclude that the pot raised seedlings perform better than the seedlings raised by broadcasting methods.