• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.81-85
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• 1989

One of the most important cultural techniques of pearl millet (Pennisetum americanum (L.) Leeke) is to encourage rapid and uniform emergence of seedlings to establish good stand and to let them grow well. Thus the objectives of the study were to investigate the effects of pre-sowing seed soaking and planting depth on dormancy breaking, germination and emergence of the seedlings, and to estimate the optimum planting season of pearl millet in Suwon, Korea. The seeds with dormancy germinated 99 to 100 percent when soaked in the H$_2$O$_2$ 1％ solution for 24 hours and rinsed with pure water, but germinated only 38％ and 83％ when soaked in pure water for 24 hours just after harvest and drying, and one month later from the harvest time, respectively. The seeds of Australia inbred line did not germinate at the constant 10$^{\circ}C$, but germinated at the constant 11$^{\circ}C$. It also was possible to estimate the optimum planting season by applying minimum temperature 11$^{\circ}C$ for germination. The minimum air temperature reached from late April in Suwon, Korea in regular years but fluctuated from late April to early May in 1986 and 1987. Thus, the safe planting season was mid-May for rapid and uniform germination of pearl millet seed. The optimum depth of planting was 2∼4cm under the optimum soil moisture condition, and 4 to 6 cm under the drier soil moisture condition. Subcoleoptile internode(mesocotyle) length increased according to increased depth of planting. Seedling crown placement also became deeper due to deeper planting of the seeds. The subcoleoptile internode length and seedling crown depth were positively correlated with actual planting depth, indicating that deeper planting would be not good for appropriate adventitious root and tiller development.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.179-186
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• 1989

According to the results from the experiments of selecting a suitable variety of forage rape and comparing productivity and nutrient quality between forage rape and oil seed rape, Velox appeared to be the most suitable variety in terms of productivity and nutrient quality at the southern area of Korea among the varieties used in the experiments. Consequently, Velox was grown under two different cultural methods, individual culture and population culture, and productivity and variation of nutrient quality during the growth period were observed and compared between the cultural methods. The results from the experiment are summarized as follows: 1. Although variations were great in plant fresh weight and plant dry matter weight among plants, individual culture showed significantly higher value in these characters at the 1 % level than population culture. Plant fresh weight and plant dry matter weight were largely dependent upon the amount of branches in case of individual culture. However, in population culture, they were equally dependent upon the amount of branches and main stem. There was no significant difference in dry matter percentage between cultural methods, and main stem showed highest dry matter percentage. 2. Content of crude protein was decreasing gradually as plants continued to grow. Individual culture showed higher content of crude protein than population culture from 90 to 120 days after sowing but vice versa from 180 days after sowing to flowering stage. Contents of fiber such as NDF, ADF, cellulose and lignin was low at the early stage of growth. It was increasing gradually as plants grew older and at the latter stage of growth plants under individual culture showed higher values in contents of fiber. 3. In vitro dry matter digestibility (IVDMD) of both stems and leaves was decreasing gradually as plants grew older. Plants under individual culture showed higher IVDMD of stems than plants under population culture, but no significant difference in IVDMD of leaves was observed between cultural methods.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.211-220
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• 2011

This study was carried out to develop salt tolerant varities of rapeseed (Brassica napus L.) which can be grown in the high salty reclaimed land. The seeds of three varieties 'Naehan', 'Tammi', and 'Halla' were treated by proton ion beams and gamma rays with 0 to 2,000 Gy. For the selection of salt tolerant lines, emergence and survival rate, and growth characteristics of $M_2$ to $M_4$ generations were investigated in the Saemangeum reclaimed fields with the different salt concentrations. The lines with potential salt tolerance were selected in the $M_4$ generation and tested indoor for their growth characteristics. There was no significant changes in the soil pH for $M_4$ generation during growth period. However, soil EC was higher in early spring than sowing period (mid October). In $M_4$ generation test, the seeds of original and selected line showed high rates of emergence and survival, as determined one month after sowing. After wintering, however, the original varieties showed the significant reduction in the survival rate, while the selected lines showed a higher survival rate and good growth, leading to the completion of their life cycle. Consequently we selected 9 lines from $M_4$ generation with better performance in growth and yield. Soil EC was $2.8{\sim}4.3dS{\cdot}m^{-1}$ during $M_4$ generation growth period. The laboratory test of the lines selected from $M_4$ generation was made for their salt tolerance potential. The selected lines showed higher chlorophyll and proline contents than the original varieties. There was also no significant difference in the emergence rate of seed between the original and selected varieties. In 200 mM natural sea salt, the $N{\gamma}600-21-1-641$ line derived from 'Naehan' was the highest in growth rate, leaf chlorophyll and proline contents. $T{\gamma}800-20-2-461$ line derived from 'Tammi' didn't show significant difference in growth rate compared to original variety in 200 mM and withered in 250 mM like other lines as time passed. $H{\gamma}200-7-1-740$ line showed similar growth and chlorophyll content compared to its original variety.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.95-95
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• 2022

Maize is one of the world's three largest crops and has a long cultivation history, and is an important crop used for various purposes such as food, feed, and industrial raw materials. Recently, the agricultural environment is changing, in which the limit of cultivation of crops is shifted to the north due to the rise in temperature due to climate change. This study was conducted in experimental field of Suwon in 2022 by setting a seeding period earlier than the sowing time to establish the North Korean agricultural climatic zone and meteorological conditions. The test cultivars were silage cultivars, Kwangpyeongok and Dacheongok. As a priming test method, it was used to directly plant seeds in the field through immersion using 4mM zinc (Zn) and 2.5mM manganese (Mn), which are trace elements for seeds. The planting season was early on March 15th, April 1st, and April 15th. The number of days from sowing to silk stage of the two cultivars sown on March 15, April 1, and April 15 was 107, 93, and 85 days for Kwangpyeongok and 109, 95, and 87 days for Dacheongok, respectively. The seed priming test did not show any difference from the control group in the growth survey up to the middle stage of growth. In another test, low-temperature recovery was confirmed through nitrogen (2-5%) foliar fertilization after 3 days, 5 days, and 7 days in refrigeration (0 degrees), a selective low temperature treatment for com in the third leaf stage. As a result of this study, it was confirmed that the low-temperature damaged com treated at 0℃ showed the same growth as that of the untreated com through nitrogen foliar fertilization. These results suggest that urea foliar fertilization for low-temperature damage reduction of corn for silage in high-latitude climates will be helpful. In addition, through the results of the study, additional studies are needed on the recovery mechanism and field application through urea foliar fertilization.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.1
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• pp.16-22
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• 2018

Oats (Avena sativa L.), which are known as one of the forage crops of Korea, have good livestock palatability and are popular to cattle farmers because of their high dry matter. However, the cultivation of double cropping in the rice field was reluctant due to the late maturing for farmers to plant rice continuously. 'Hi-early', a winter oats for forage use, was developed by the breeding team at National Institute of Crop Science, RDA in 2016. It was derived from a cross between '517A2-121'(IT133383) and 'CI7604' (IT133379). Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Suwon, Iksan and Jeonju, respectively. After preliminary and advance yield test for 2 years, 'SO2004015-B-B-23-1-3-7', designated as a line name of 'Gwiri92', were subsequently evaluated for earliness and forage yield during 3 years in four parts such as Jeju (upland), Yesan (upland), Iksan (upland), and Jeonju (paddy), from 2014 to 2016, and finally named as 'Hi-early'. Cultivar 'Hi-early' has the characteristics of medium leaves of green color, thick diameter culm, and medium grain of brown color. Over 3 years, the heading date of 'Hi-early' was about 9 days earlier than that of check cultivar 'Samhan' (April 26 and May 5, respectively). Average forage fresh yield of 'Hi-early' harvested at milk-ripe stage was similar to check cultivar ($40.2tone\;ha^{-1}$ and 40.0 tone ha-1, respectively), and dry matter yield also was similar to check cultivar (14.2 tone ha-1 and $14.0tone\;ha^{-1}$, respectively). Cultivar 'Hi-early' was lower than the check cultivar 'Samhan' in terms of the protein content (6.2% and 7.0%, respectively) and total digestible nutrients (61.0%, and 62.5%, respectively), while the TDN yield was more than the check ($7.91tone\;ha^{-1}$ and $7.64tone\;ha^{-1}$, respectively). Fall sowing cropping of 'Hi-early' is recommended only in areas where average daily minimum mean temperatures in January are higher than $-6^{\circ}C$, and it should not be cultivated in mountain areas, where frost damage is likely to occur.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.112-118
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• 1997

This study was conducted to obtain basic information on the desalinization in newly reclaimed tideland. A desalinization experiment with leaching method was carried out using the soil samples collected in Haenam tideland, and the early growth response of winter barley to salt stress during the desalinization was investigated by measuring emergence rate, plant height, leaf area and fresh weight. The soil in Haenam tideland was saline-sodic with 59mS / cm of electrical conductivity and pH 8.0, and the soil texture was silty loam with 16％ clay and 75％ silt. Depth of water for desalinization(DWD) to decrease the electrical conductivity below 4mS /cm was 140mm in 5cm depth soil and 240mm in 20cm depth soil. The value of pH of soil and leaching water increased from 8.0 to 8.3 until the electrical conductivity decreased to about 6mS / cm during the desalinization. .The emergence rate of winter barley was over 75％ in the DWD above 80mm and showed no significant difference with the DWD. The DWD for the normal growth of winter barley seedling was above 120mm at 1 and 2 weeks after sowing(WAS), and above 160mm at 3 and 4 WAS. The leaf area and fresh weight showed no response for salt stress with the DWD above 12mm at 2 WAS, and above 16mm at 3 WAS. It was estimated that the electrical conductivity of soil saturation extract for the normal growth of winter barley during early seedling growth stage in new reclaimed tideland would be below 9mS / cm in 20cm depth soil.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.202-207
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• 2002

To establish the seed treatment method of the gamma radiation for germination enhancement of bottle gourd(Lagenaria siceraria Standl.) and pumpkin(Cucurbita ficifolia Bouche), seeds were irradiated with the dose of 1$\sim$20 Gy of the gamma radiation. The germination rate in irradiated group was higher than that of the control, depending on seed condition. In the case of bottle gourd, the germination rate of 70$\sim$80% germinative seed was increased at 4$\sim$20 Gy irradiated groups. Especially, it was the highest at 4 Gy irradiated group. The germination rate of 80$\sim$90% germinative seed was the highest at 4 Gy irradiated group. The germination rate of 70$\sim$80% and 80$\sim$90% germinative seed at 4 days after sowing was increased 66% and 26% at 4 Gy irradiated group, respectively. In the case of pumpkin, the germination rate of 70$\sim$80% and 80$\sim$90% germinative seed was increased at 2 Gy and 8 Gy irradiated group, respectively. Effect of the low-dose gamma radiation on the early growth was enhanced depending on their germination enhancement. Especially, it was the highest at 2 Gy irradiated group of 70$\sim$80% germinative seed of pumpkin. Catalase activity of bottle gourd was increased at 4 Gy irradiated group. Catalase and peroxidase activity of pumpkin were increased at 2 Gy and 8 Gy irradiated group. These results suggest that the germination, early growth and physiological activity of bottle gourd and pumpkin seeds could be promoted by the low dose gamma radiation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.429-438
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• 2007

Early growth vigor(EGV) is one of the physiological characteristics that may contribute to the increase of genetic yield potential and radiation use efficiency by closing the canopy earlier. To estimate the genotypic variation of EGV, determine the relationships among the related traits, and identify the rapidly growing genotypes and indirect indicator for selection in breeding program, the evaluation of EGV and EGV-related traits was conducted for a total of 140 rice varieties consisting of 101 Korean, 25 Northern China and 14 IRRI-bred rice varieties in a serial sowing experiment in plastic rain shelter and plastic-covered nursery bed in 2003. EGV defined as the amount of leaf area and/or dry weight produced early in the season and the EGV-related traits such as length and breadth of the $2^{nd}\;and\;3^{rd}$ leaves showed highly significant positive correlation with the embryo and seed weight. Especially, the genotypic variation in the length of the third leaf was explained over 90% of genotypic variation in the seed weight. Owing to a large effect of seed size on EGV and its related traits, vigor measurements were adjusted based on their linear or exponential relationships with seed weight for excluding the seed weight effect. EGV and its related-traits adjusted for seed weight also showed big variation among genotypes. Increased EGV was genetically correlated with increases in breadth and length of early leaves. The broad-sense heritability for EGV was significantly high(81%), but lower than those of leaf breadth(90% for the $2^{nd}$ leaf and 93% for the $3^{rd}$ leaf) and length(87% for the $2^{nd}$ leaf and 89% for the $3^{rd}$ leaf). Significantly positive genetic correlations were found between EGV and the breadth and length of early leaves. The high heritability of early leaf breadth and length coupled with their strong genetic correlation with EGV indicated that the breadth and length of the $2^{nd}\;and\;3^{rd}$ leaf would be used as good indirect indicators for EGV selection in rice breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.1-29
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• 1969

Experiments on rice concerning it s varieties, fertilization, seedling dates and herbicides have been conducted to determine the most desirable method of direct sowing cultivation on dry paddy field land in the middle part of Korea. The results obtained at the Office of Rural Development of Choongnam Province are as follows:. 1. Sixteen different derivatives from the main varieties of low land rice were cultivated on a dry paddy field by the direct sowing method; at the same time, a few varieties were tried adopting the common transplanting cultivation method. The yield and yield factors from these two groups were examined to give the following results: a) Compared to the common transplanting cultivation, the direct sowing method showed remarkably increased number of panicles while the number of flowers per panicle was shown to be significantly decreased. The maturing ratio was detected to be lowered. The yield horn them differed according to the different varieties : good yield was obtained from Hokwang while Norin ＃25 proved poor when compared with the common transplanting cultivation method. b) Among sixteen varieties tested, Sunsou, Norin ＃25, Jaigou, Hokwang, Palkueng and Gosi showed comparatively high yields, their yield being more than 325 kilograms per 10 Are, but Nampoong, Paldal, Nongkwang, Norin ＃29, Eunbangju ＃101 and Shiro gane showed less yield, their yield being less than 271 kilograms per 10 Are, the relations between the yield and the yield factors can be summarized as follows; Number of varieties and their rice yield. 1) The varieties which were great in the, number of panicles and high in yield=Jaigoun, Hokwang Palkueng and Gosi. 2) The varieties which were low in the number of panicles and high in yield=Sounsou and Norin ＃25. 3) The varieties which were great in the number of panicles and poor in yield=Eunbangju ＃101 and Sirogane. 4) The varieties which were poor in the number of panicles and poor in yield: Nampung, Paldal and Norin ＃29. Number of flowers per panicle and yield. 1) The varieties which were great in the number of flowers per panicle and high in yield: Sounsou, Norin ＃25 and Gosi. 2) The varieties which were poor in the number of flowers per panicle and high in yield ; Jaigoun, Hokwang and Palkueng. 3) The varieties which were great in the number of flowers per panicle and poor in yield: Paldal and Nampung. 4) The varieties which were poor in the number of flowers per panicle and poor in yield: Norin ＃29. Eunbangju ＃101 and Sirogane. Maturing ratio and yield. 1) The varieties which were high in the maturing ratio and high in yield: Jaigoun, Sounsou, Norin ＃25 and Palkueng. 2) The varieties which were low in the maturing ratio and high in yield: Hokwang and Gosi. 3) The varieties which were early maturing rat io and low in yield: Hokwang and Gosi. 4) The varieties which were late maturing ratio and poor in yield: Eunbangju ＃101, Nampungand Sirogane 1, 000 grain weight and yield. 1) The varieties which were heavy in 1, 000 grains weight and high in yield=Norin ＃25 and Hokwang. 2) The varieties which were light in 1, 000 grains weight and high in yield=Sounsou and Jaigoun. 3) The varieties which were heavy in 1, 000 grains weight and poor in yield=Nongkwang and Eunbanju. 4) The varieties which were light in 1, 000 grains weight and poor in yield=Norin ＃29 and Sirogane. 2. The experiment on fertilization showed that the most desirable amount to be given per 10 Are was 10 kilograms of Nitrogen, 5 kilograms of phosphate and 6 kilograms of potassium; and when the Nitrogen given exceeded 8 kilograms, its effect was better when given in amsll consecutive (split) amounts, while the maturing ratio and the number of the flowers per panicle increased when Nitrogen was given in large amount during the later stage of growth of rice. 3. The experiment on the date and amount of seedling showed that the tested variety, Sunsou gave the best results when planted on the days between 25 April and 10 May. Eight liters per 10 Are were preferable if planted early and 12 liters per 10 Are if planted late. The reason why the later planting gave a lower yield was that the number of flowers per panicle was fewer. 4. The experiment on the irrigation for rice with direct sowing cultivation immersed in water showed that it was the most satisfactory when irrigated on 25th June, 55 days after its seedling, its plot giving the best yield. The plots 10th June and 15th July showed just as good results. However, irrigated later, than 15th July it showed lower yields. 5. Compared to the yield of the plot controlled by the common method, the yield from the plots treated with chemical herbicide such as LOROX, TOK, PCP, SWEP, Mo-338 on dry condition soil seemed poorer, but significant difference was not found statistically. On the other hand in the case where chemical herbicides such as TOK, Mo-338, Stam F-34 or ORDRAM were used after irrigation, the yield from the ORDRAM and TOK treated plots did not show significant differences compared to the common hand weed controling method, but those treated with chemicals other than the above showed a lower yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.123-133
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• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.