• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.59-67
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• 1992

The duration of raising seedling of infant rice seedling(IRS) in machine transplanting is 8 to 10 days. This experiment was conducted to investigate the minimum duration of IRS's raising seedling and its method by the combination of several treatments such as plant growth regulator, root-break-seat and temperature. The rice seeds of Hwaseongbyeo was soaked in the solution of metalaxyl for 24 hours at room temperature. Metalaxyl (25% wettable powder), a fungicide, was used in 1, 000 times dilution as a promting substance on the root-mat formation of IRS. The application of fungicide in the nursery soil for the controlling of damping-off and physiologyical seedling rot was omitted due to the metalaxyl seed-soaking treatment. Seeding rate was 220g per seed tray (30$\times$60$\times$3cm). To promote the root-mat formation of IRS, the sheets of polyethylene vinyl and absorptive paper were placed bottom the seed tray. The root-mat formation of IRS was promoted at higher temperature and longer duration of raising seedling. The metalaxyl-treated seeds markedly increased the root length and rooting activity of IRS as compared with the control, thus the root-mat formation was excellent. The absorptive paper with polyethylene vinyl as root-break-seat showed a better root-mat formation compared with control, polyethylene vinyl, alone. The minimum duration of raising seedling of IRS was 5 days after sowing based on the root-mat formation and seedling height under the condition of metalaxyl seed treatment, absorptive paper with polyethylene vinyl as a root-break-seat and the raising seedling temperature 30/2$0^{\circ}C$ (day /night).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.149-153
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• 1999

Prediction of rice developmental stage is necessary for proper crop management and a prerequisite for growth simulation as well. The objectives of the present study were to find out the relationship between the plastochrone index(PI) and the developmental index(DVI) estimated by non-parametric phenology model which simulates the duration from seedling emergence(DVI=0) to heading(DVI=l) by employing daily mean air temperature and daylength as predictor variables, and to confirm the correspondency of developmental indice to panicle developmental stages based on this relationship. Four japonica rice cultivars, Kwanakbyeo, Sangpungbyeo, Dongjinbyeo, and Palgumbyeo which range from very early to very late in maturity, were grown by sowing directly in dry paddy field five times at an interval of two weeks. Data for seedling emergence, leaf appearance, differentiation stage of primary rachis branch and heading were collected. The non-parametric phenology model predicted well the duration from seedling emergence to heading with errors of less than three days in all sowings and cultivars. PI was calculated for every leaf appearance and related to the developmental index estimated for corresponding PI. The stepwise polynomial analysis produced highly significant square-rooted cubic or biquadratic equations depending on cultivars, and highly significant square-rooted biquadratic equation for pooled data across cultivars without any considerable reduction in accuracy compared to that for each cultivar. To confirm the applicability of this equation in predicting the panicle developmental stage, DVI at differentiation stage of primary rachis branch primordium was calculated by substituting PI with 82 corresponding to this stage, and the duration reaching this DVI from seedling emergence was estimated. The estimated duration revealed a good agreement with that observed in all sowings and cultivars. The deviations between the estimated and the observed were not greater than three days, and significant difference in accuracy was not found for predicting this developmental stage between those equations derived for each cultivar and for pooled data across all cultivars tested.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.04a
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• pp.99-100
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• 1998

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.61-66
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• 1987

Germination and seedling length of soybean seeds (cultivar: Williams) with and without polyethylene glycol-8000 (PEG) treatments were measured following preconditioning at two temperatures (15 and 30$^{\circ}C$) and two moisture levels 〔low (30 percent) and high (50 percent seed water content)〕 for 0, 2, 4, or 8 days. A split-split plot in time was used with four replications. Observations were made after two days of germination at 30$^{\circ}C$ Seedling growth accelerated with two days of preconditioning at 30$^{\circ}C$, but was reduced as preconditioning duration increased up to eight days at the same temperature. PEG treated preconditioned seeds exhibited reduced moisture uptake and seedling growth. Preconditioning at a high moisture level increased seedling moisture content and also increased seedling length until four days of preconditioning duration. Seedling dry weight decreased when preconditioning temperature was 30$^{\circ}C$ and when the high moisture level of preconditioning was continued for eight days.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.12-17
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• 2002

Tn establish the criteria for appropriate seedling production method in the summer, the effect of container size and seedling age on the growth and yield were evaluated with tomato. The seedling quality was higher when seedlings were grown polyethylene in 9cm pots than in 72 cell plugs. Seedling quality increased with increase in seedling age in polyethylene pots, whereas seedling age did not affect seedling quality in plug trays. Fruits matured earlier on plants started from pot-grown transplants for a long duration than with plug tray-grown transplants for a shorter duration. Not only total yield in 4 months, but the early yield in the first 2 months, was higher with pot-nursed transplants than with plug tray-nursed transplants. With pot-grown transplants, The early yield in initial 2 months was the lowest in 25 day-old transplants, whereas there was no significant differences between 35- and 45-day-old transplants. Seedling age did not affect the cumulative yield for 3 months after the first harvest. With plug tray-grown transplants, the cumulative yield tar initial 3 months was the highest in plants grown for 35 days in the nursery, followed by 25 day and 45 day. However, there were no significant differences among seedling ages in the total yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.239-243
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• 2008

This experiment was carried out to elucidate the appropriate split application method of nitrogen fertilizer in infant rice seedlings which show poor seedling growth resulted from extended seedling nursery duration more than 12 days. The 16 day-old infant rice seedling (DOIRS) showed poor seedling growth than 8 day-old seedling. Early growth of transplanted 16 DOIRS was poor, compared with that of transplanted 8 DOIRS. However, the poor plant growth estimated by plant height, tiller number, and the number of newly developed roots was compensated by 70-0-30% (basaltillering-panicle initiation) of nitrogen split application. In 70-0-30% plots among split nitrogen application methods, tiller number, biomass, and leaf area at heading stage of rice showed the highest values. Sixteen DOIRS plots showed lower grain filling and 1000-grain weight, resulted in lower yield of rice than 8 DOIRS plots in the same nitrogen split application. However the lower yield in 16 DOIRS plots was recovered by 70-0-30% of nitrogen split application method to a similar level in 8 DOIRS plots in which nitrogen was split applied by 40-30-30%.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.19-22
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• 2008

This experiment was conducted at Sangji university in Wonju, Korea from 2005 to 2006. The results obtained were summarized as follow; The Chung-ju local variety was tested to find out the possibility of transplanting of seedling as a after-barley crop. When transplanting of seedling for a after-barley crop was test, this short-day plant flowered from september 1 to september 3, showing no connection with sowing time nor seedling periods. The yield of seeds per 10a was affected by both the sowing time and the seedling periods and its peak in the plots sowed on May 15 and transplanted on June 24(40 days seedling).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.259-267
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• 2010

This study was performed at Rice and Winter Cereal Crops Department of NICS during 2007 and 2008 to investigate the characteristics of rice leaf emergence and to obtain basic data which can be used for rice growth simulation model by which we can forecast rice growth stage and heading date accurately under different cultivars, transplanting date, and climatic conditions. To confirm leaf emergence rate according to rice maturing ecotype, we surveyed the leaf emergence rate and heading date of Unkwangbyeo, Hwayoungbyeo and Nampyeongbyeo which are early maturing, medium maturing and medium-late maturing cultivars, respectively, according to seedling raising duration and transplanting time. When seedling duration was 15 days, the growth duration between transplanting time and completion of flag leaf emergence on main culm were 51.5~78.3 days in Unkwangbyeo, 55.3~87.9 days in Hwayoungbyeo and 58.4~98.4 days in Nampyeongbyeo, respectively. When seedling duration was 30 days, they were 50.1~75.5 days in Unkwangbyeo, 52.4~84.7 days in Hwayoungbyeo and 56.4~93.8 days in Nampyeongbyeo, respectively. As transplanting time delayed, the emerged leaf number after transplanting decreased in all rice cultivars. The cumulative temperature between transplanting time to completion of flag leaf elongation on main culm were $1,281^{\circ}C{\sim}1,650^{\circ}C$ in Unkwangbyeo, $1,344^{\circ}C{\sim}1,891^{\circ}C$ in Hwayoungbyeo and $1,454^{\circ}C{\sim}2,173^{\circ}C$ in Nampyeongbyeo, respectively. Leaf emergence rate on main culm were precisely represented by equation, y = $y_0$ + a / [1 + exp( - (x - $x_0$) / b)]^c, when we used daily mean temperature as variable.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.282-292
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• 2015

Seeds of colored rice generally have high anthocyanin and flavonoid content but some cultivars have low seed germination rate. This defect poses unstable seedling establishment in nursery bed. The seed gravity variations of 10 colored rice varieties and its effect on germination, seed soaking duration and their optimum seeding rates for seedling raising in machine transplanting were investigated in the experiment. Based on seed gravity distribution of the 7 black- and 3 red-colored rice varieties at three levels of seed gravity (1.0<, 1.0~1.06, 1.06>), the black colored seeds such as Josaengheugchal and Sinmyungheugchal had high amount of specific gravity of below 1.0 ranging from 86~ 96%, while they had only 3~13% of seeds in specific gravity above 1.06. Sintoheugmi, Heugjinju, Heugnam, Heugkwang had various mass of seeds, showing 29~44% for specific gravity of below 1.0, 24~39% for 1.0~1.06 and 25~45% for above 1.06. On the other hand, the red colored rice such as Hongjinju, Jeogjinju and Geonkanghongmi had high percentage of specific gravity of above 1.06 with 84~86% while they had only 9~12% of specific gravity below 1.0 similar to Ilmibyeo of noncolored rice. The black colored seed generally showed low germination percentage, slow germination speed and long mean germination time, and low water absorption rate as compared with seed of the red colored rice which was similar to those of Ilmibyeo used as a control cultivar. The black colored seeds took 2~4 days longer seed soaking duration than the red colored rice before germination. This was related to high seed amount of specific gravity below 1.0 in black colored rices. The high amount of seed gravity above 1.06 in the colored rice seeds was positively correlated with percentage of germination, germination speed and mean germination time, ripened grain ratio and water absorption. Seed gravity distribution effect were less pronounced between back- and red- colored seeds in seedling emergence. The black colored rice has slightly lower normal seedling emergence rate than the red colored rice and Ilmibyeo in the seedbed soil due to high percentage of ungerminated seed. Normal seedling emergence rate of the black colored rice in the seedbed was 75.2~82.2% for 10-day old seedling and 85.3~ 90.9% for 30-day old seedling which was lower by 4.5~ 8.0% and 0~3.3%, respectively, than the red colored rice. Based on the normal seedling number per tray of Ilmibyeo for seeding rate of 10-day and 30-day old seedlings, the recommended seeding rate of black colored rice is 200~ 220g seeds for the 10-day old seedling and 110~130g for the 30-day old seedling in transplanting rice while the seeding rate of the red colored rice was 220g seeds for the 10-day old seedling and 130g for the 30-day old seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.531-536
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• 1994

Drainage duration before seeding and furrow depth desirable for establishment and growth in direct drill seeding of rice on puddled paddy soil were investigated. Furrow depths tested were 2, 4 and 6cm in combination with drainage duration 2, 4, and 6days. Dongjinbyeo was used and seeded on May 11, 1993. Seedling establishment were improved by longer drainage duration and by shallower furrow. Lodging occurred moderately at furrow depth of 2cm with 4 and 6days of surface drainage before seeding. This lodging might be attributable to the shallow burying of shoot below soil surface. Rice yield was highest at furrow depth of 4cm with 4days drainage before seeding. In considering seedling establishment and yield, desirable drainage duration before seeding and furrow depth might be 4days and 4cm, respectively. Cone(115g) penetration depth, dropped at 1m above soil surface, was 6 to 7cm on the date after 4days drainage before seeding.