• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.2
• /
• pp.212-220
• /
• 1995

The optimum seeding date and the suitable seeding period for puddled drill seeding of rice at southern plain area were determined by using Sinunbongbyeo (early maturing variety), Hwaseongbyeo(medium maturing var.) and Dongjinbyeo (late medium maturing var.) at National Honam Agricultural Experiment Station from 1993 to 1994, Seedling stand was decreased significantly at seeding on April 25 in all varieties, Threshold seed-ing dates for stable ripening was estimated as June 10 in Sinunbongbyeo, May 31 in Hwaseongbyeo and May 25 in Dongjinbyeo, The 1,000 grain weight and the ripened grain rate were highest at seed-ing on May 10 or May 25 in all varieties, and decreased significantly at seeding on June 25 in Sinunbongbyeo and seeding after June 10 in Hwaseongbyeo and Dongjinbyeo, The optimum average air temperature for 40 days after heading was 22.6$^{\circ}C$ for highest ripening rate and 22.0$^{\circ}C$ for heaviest 1,000 grain weight. The optimum seeding date for highest yield was May 9 in Dongjinbyeo, May 13 in Hwaseongbyo and May 15 in Sinunbongbyeo.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.468-476
• /
• 2020

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m^-2·s^-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m^-2·s^-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m^-2·s^-1. In the aeroponic system, seedlings raised at 60 μmol·m^-2·s^-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m^-2·s^-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m^-2·s^-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m^-2·s^-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m^-2·s^-1.

• Korean journal of applied entomology
• /
• v.40 no.2
• /
• pp.137-141
• /
• 2001

This experiment was conducted to investigate the control effect of nuclear polyhedrosis virus and NeemAzal-T/S on Spodoptera litura larvae. In laboratory test, values of$ LT_{50}$ and $LT_{95}$ when treated with S. litura nuclear polyhedrosis virus (SINPV) $1$\times$10^{8}$ PIBs/ml plus NeemAzal-T/S 200 ppm were 1.94 and 8.33 days, respectively. Control effect of the combination of SINPV $1$\times$10^{8}$ plus NeemAzal-T/S 200 ppm was higher than the other concentrations. This mixed treatment could reduce LT$_{95}$ by 3 days. When SINPV alone was sprayed to the S. litura larvae reared on chinese cabbage seedling, the mortalities were 10.7~6.7% at 4 days after treatment. In combinations of SINPV plus NeemAzal-T/S at each level of concentration, the mortalities appeared faster and higher at 4 days after application than single treatment. Especially, the mortalities by combinations of SINPV $1$\times$10^{8}$ /PIBs/ml plus NeemAzal-T/S at 75~200 ppm were 100% at 9 days after treatment. The body weight of untreated larvae was increased 9.4-folds from 235 mg to 2194 mg after 7 days. However, the increasing levels of larval weight were 4.8- and 7.0-folds in the separate treatments of NeemAzal-T/S and SINPV, respectively. Whereas in the combinations of SINPV $10^{4~8}$ PIBs/ml plus NeemAzal-T/S 75~200 ppm, larval weight was increased 3.9 to 2.9-folds. These results showed that the mortality and inhibition of larval weight in the combination of SINPV and NeemAzal-T/S were highly enforced by synergistic effect.

• Journal of Bio-Environment Control
• /
• v.14 no.2
• /
• pp.89-94
• /
• 2005

This study was conducted to investigate the effect of nonwoven fabrics weight(Ounce) on growth, quality and yield of oriental melon (Cucumis melo L. var. makwa Mak.). Seedling of 'Gumssaragi-Eunchun' was grafted on 'Shinthozoa' root stock. In this study, The minimum air temperature in 6 ounce at night was $4.8^{\circ}C,\;6.9^{\circ}C$ in 9 ounce, $7.9^{\circ}C$ in 12 ounce and $8.0^{\circ}C$ in 15 ounce, respectively. Leaf length, stem diameter, leaf numbers, leaf area, fresh weight and dry weight for 30 days after planting were better in high minimum air temperature at night than in low minimum air temperature, particularly leaf areas of the plant in 9 ounce was $370cm^2$ at 30 days after planting, $116\%$ in 12 ounce, $129\%$ in 15 ounce. The xylem exudates amount in 9 ounce for 24 hours just after basal stem abscission was 10.1mg. It was 1.2 times much in 12 ounce and 1.9times much in 15 ounce than in 9 ounce at 30 days after planting. The blooming of female was faster by 6 days in 15 and 12 ounce but was delayed by 3 days in 6 ounce than 9 ounce, and the days of blooming to harvesting were shorter by 3 days in 15 ounce and 4 days in 12 ounce but was delayed by 3 days in 6 ounce than in 9 ounce. Fruit weight, fruit length, fruit diameter, flesh thickness, soluble solids, and total yield was the highest in 15 ounce followed by 12 ounce,9 ounce and 6 ounce. Fermented fruit rate was the highest in 6 ounce followed by 9 ounce, 12 ounce and 15 ounce, and marketable fruit rates were 15, 12, 9 and 6 ounce in order. Compared to 1,781kg yield per 10a of 9 ounce, $19\%\;and\;49\%$ was increased under 12 ounce and 15 ounce but $47\%$ were decreased 6 ounce.

• Journal of the Korean Society of International Agriculture
• /
• v.31 no.3
• /
• pp.278-285
• /
• 2019

The experiment was implemented to gain basic data for stable proso millet (Panicum miliaceum L.) production through germination viability and establishment uniformity based on seed refining under seed selection with specific gravity of proso millet seed. Seeds of three proso millet cultivars were carefully selected by adjusting NaCl into 9 levels (1.000, 1.005, 1.010, 1.015, 1.020, 1.025, 1.030, 1.035, 1.04 g·L^-1), and their standard germination rate, seeding quality and field emergence rate were investigated. Proso millets showed heavier thousand seed weight as specific gravity high. In standard germination, all of the 3 cultivars of selected seeding showed at least 91% germination rate. With respect to the 1.040 g·L^-1 selection by specific gravity, 'Hwanggeum' had 98.9%, 'Ibaekchal', 99.4%, and 'Hwangsilchal', 98.9%, recording the highest. Seeding quality was investigated and it was found that, compared with the non-selected seeds, selected seeds had longer plant heights and averaged 2.0, 2.2 and 1.9 cm, respectably. In terms of leaf length, only 'Hwanggeum' and 'Ibaekchal' showed distinctive differences. No significance was found in stem diameter and SPAD. The seeds selected using specific gravity all had longer or heavier average root length, root weight and stem weight. Compared with non-selected seeds, the specific gravity of 1.040 g·L^-1 had longer root lengths of 2.9, 3.0 and 2.9 cm. 1.040 g·L^-1 was also found to have the heaviest root weight, and stem weight. The field emergence viability investigation found significance solely in the mean emergence time (MET) by the cultivar. High significance was found in percent emergence (PE) and emergence rate index (ERI) in the specific gravity for the selection of seeds. All of the three cultivars showed higher PE and ERI as specific gravity selection high. The 1.040 g·L^-1 specific gravity selection had the highest PE of 90.7, 85.3 and 92.8%. For productivity increase based on improved proso millet germination rate and enhanced establishment uniformity, it seems favorable to employ 1.040 g·L^-1 specific gravity selection using salt solution.

• Korean Journal of Environmental Agriculture
• /
• v.16 no.2
• /
• pp.130-135
• /
• 1997

Tomatoes are flooded differently 0, 5, 10 and 15cm, according to the developing stages such as flowering stage under the condition of greenhouse. Along with this, they are treated according to the time condition such as 6, 12, 24, 48 and 120 hours. The results obtained are summarized as follows. Plant height decreased in the depth of $0{\sim}10cm$ for over 48 hours, in the depth of 15cm for over 24 hours. Number of leaves was the same as in control, and it decreased over. Number of flowers and fruit setting of individuals decreased conspicuously according as the depth and the hours got greater and longer. Adventitious root occurred remarkably in the depth of $0{\sim}10cm$, for over 24 hours and in the depth of 15cm, 12 hours. Epinastic curvature increased greatly as the depth and the hours got greater and longer. Diffusion resistance of stomata cell increased as the depth and the hours got greater and longer. Diseases occurred conspicuously as the hours of flooding got longer rather than as the depth greater. The preventing of diseases caused by insecticide was observed, but it was not greater than in the seedling and transplanting stage. Fertilization was effective in the case of increasing the weight of shoot. Number of fruits per plant did not decrease in the depth of 0cm up to 24 hours, but decreased on the deeper level of flooding and increased as the hours got longer. Moreover with the exception of 120 hours per respective depth of the treatment, average weight of a fruit got greater as the depth and the hours got greater and longer. In the case of epinastic curvature and diffusion resistance, there was negative correlation between all the other investigated characters and positive correlation between weight of a fruits and average weight of a fruit.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.251-256
• /
• 2010

Objective of this research was to investigate the influence of $NH_4^+$ and $NO_3^-$ ratios in liquid feeding on the growth of snapdragon 'Potomac Red' and changes in medium chemical properties. The seeds were sown into 200 plug trays and fertigated once a week with nutrient solution containing various ratios of $NH_4^+$ and $NO_3^-$ such as 0 : 100, 27 : 73, 50 : 50, 73 : 27, and 100 : 0. The total N concentrations were adjusted to 50, 100 and $150\;mg{\cdot}L^{-1}$ in plug stages of 2, 3, and 4, respectively. Determination of seedling growth and analysis of plant tissue and root medum were conducted at 56 days after sowing. The treatment of 27 : 73 ($NH_4^+:NO_3^-$) had the greatest plant height, fresh weight, and dry weight. The N and P contents in 27 : 73 ($NH_4^+:NO_3^-$) treatment based on the above ground plant tissues were 2.39 and 0.39%, respectively, which were the greatest among treatments. The elevation of $NH_4^+$ ratio in fertigation solution decreased tissue Ca and Mg contents, but that did not influence tissue K content. The variations in $NH_4^+:NO_3^-$ ratios impacted the soil solution pH and the difference among treatments had been severe since three weeks after sowing. Elevation of $NH_4^+$ ratios in fertigation solution increased electrical conductivity and concentrations of K, Ca, and Mg in soil solution of root medum. The $NH_4^+$ and $NO_3^-$ concentrations in the soil solution were high in weeks 2, 3, and 4, then decreased gradually as the biomass of seedlings increased. Medium P concentration decreased gradually as seedlings grew, but statistical differences were not observed among treatments.

• Korean Journal of Weed Science
• /
• v.8 no.3
• /
• pp.273-282
• /
• 1988

The seventeen barnyardgrass [Echinochloa crus-galli (L.) Beauv.] accessions, which were collected national-widely in 1986 and selected two times through 1987, were experimented at 1988. To study the degree of ecological variations of the collected accessions of native barngardgrass species as a weed, the experiment was conducted with Wagner pots in size of 1/5000a and under P.E. film house. Among 57 characters, 100 grains weight, rate of tiller increase from transplanting to 30 days, the number of the maximum tillers and rate of dry weight increase from 15 DAS to 22 DAS were become intra-specific variarions as higher coefficient of varation than 30%, the size of the first leaf, fresh weight and dry 22 seedlings, rate of productive tiller, panicle number and tillering divergence made intra-specific variations as more and less C. V. than 25%, while the required days upto heading since seeding at June 6. rate of fresh/dry weight and plant height of 22 days old seedling made intra-specific variations as the coefficient of variation of about 50%. Among the attributes the color in leaf, leaf sheath, mid-ribs, node, spike, grain, and plant type, length of leaf marginal tooth, grain shape, purple bend on leaf were seemed useful to indentify the accessible specific.

• Journal of Bio-Environment Control
• /
• v.20 no.4
• /
• pp.373-381
• /
• 2011

This study was carried out to investigate the growth and physiological responses to shading treatment of 1-year-old containerized seedling of Quercus myrsinaefolia. Experimental process was conducted in a facility that consisted of compartments under the lighting control with full sunlight and shading (35%, 55% and 75% of full sunlight). Height and root collar diameter growth were high in the seedlings under both 35% and 55% shading. Regardless of shading level, root collar diameter growth lasted for more than 4 weeks compared to height growth. Highest H/D ratio was observed in the seedlings under 35% shading as 4.31, and the lowest ratio was 3.63 under 75% shading. It was found that seedlings under 55% shading showed highest dry mass production, which was followed in seedlings under 35% shading. In case of leaf dry weight ratio (LWR) after shading treatment, the highest value was 0.53 under 55% shading, and followed in seedlings under 35% shading as 0.52. But root dry weight ratio (RWR) was highest as 0.36 under 75% shading (highest level of shading). In terms of shading treatment, it was found that the higher level of shading had a tendency toward the higher content of chlorophyll a and the higher total chlorophyll content in the leaves of Quercus myrsinaefolia, but there was no significant difference in the content of chlorophyll b depending on the level of shading. It was found that high photosynthesis and transpiration rate were more correlated with high level of shading than full sunlight, but the rates of seedlings had a tendency to be higher under 35% and 55% shading than under 75% shading. The results on growth and physiological responses to different shading levels of 1-year-old containerized seedlings of Quercus myrsinaefolia could be useful in setting up the optimum light intensity for growth, and in estimating the shade tolerance of the species.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.50-55
• /
• 2013

The objective of this research was to investigate the impact of Ca fertilizer on the growth of mother plants, physiological disorders, and occurrence of daughter plants in propagation of 'Seolhyang' strawberry through plastic bag cultivation. To achieve this, chemicals of 1.125 mM $Ca(OH)_2$, 0.375 mM $MgCl_2$, 1.250 mM KCl were blended and designated to combined fertilizer (CF). Then, the effect was compared to the treatment of no Ca application (control) and a commercial fertilizer, CalMag (13-0-1.9-16-6:N-$P_2O_5$-$K_2O$-CaO-MgO), when those were applied every two weeks with controlled electrical conductivity (EC) of solution such as 0.6 or 1.0 $dS{\cdot}m^{-1}$. The number of plants showing Ca deficiency symptoms was the highest in control treatment, but those decreased significantly in CF or CalMag treatments. The differences between CF and CalMag in appearance of Ca deficient plants were not significant when two fertilizers were applied with same EC. The fresh and dry weights of mother plants were the greater in the treatments of CF or CalMag than those of control treatment. The treatments of 1.0 $dS{\cdot}m^{-1}$ of CF or CalMag were more effective than those of 0.6 $dS{\cdot}m^{-1}$ on the fresh and dry weight of the mother plants. The runner lengths in the treatment of 1.0 $dS{\cdot}m^{-1}$ of CF were the longest among the all treatments tested. The treatments of 1.0 $dS{\cdot}m^{-1}$ were more effective than those of 0.6 $dS{\cdot}m^{-1}$ of CF or CalMag in lengths and fresh and dry weight of runners. The fresh and dry weights of daughter plants were heavier in the treatments of CF than those of CalMag. Based on the above results, we concluded that the Ca deficiency in raising 'Seolhyang' strawberry can be lessened by the application of Ca containing fertilizers, but combined application of Ca, K and Mg was more effective than that of Ca alone for seedling production.