• Horticultural Science & Technology
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• v.19 no.3
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• pp.329-333
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• 2001

The study was performed to investigate the effect of a plug culture method in the early stage of a potato breeding program. The 105, 200 and 288-cell plug trays were used for raising potato seedlings. The % germination in plug trays ranged between 94 and 96%. Percent tuberization measured at 50 and 60, and 70 days after sowing was the greatest in 105-cell and 200-cell trays, respectively. However, tuberization was most delayed in 288-cell trays. Thus, it is considered that 105-cell tray is the most effective for the selection of early maturing plants. Plant maturity was determined by the morphological characteristics at the seedling stage of stolons cultured in plug trays. Most of seedlings with shorter stolons at seedling stage (1st generation) were the early-maturing, while most of seedlings with longer stolons were the late-maturing at the clonal stage (2nd generation). These results mean that the plant maturity in the early potato breeding program can be effectively grouped by observing the morphological characteristics of stolons after plug culture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.254-260
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• 1984

As a basic study for development of early wheats an experiment was carried out at four sites of Korea by use of 60 varieties. Analysis of variance for heading and maturing dates revealed that there were highly significant among varieties, but not significant among variety x location-interactions, thus indicating the stable response for earliness at all locations of each variety. Grain filling periods of each variety showed the stable response at all locations like those of heading and maturing dates, however, there showed significance among locations for early group, and among varieties for late group. High correlations were between growth habit and winter survival for early varieties, and between shortday length and grain filling period for late one. Interior factors most closely related to heading date were growth habit and winter survival, and winter survival showed highly negative correlation with heading date. It needs to breed the early wheats adaptable for southern and/or northern areas separatively. The earlier heading and maturing dates of wheats were, the shorter internodes of culm are, appearing the outstanding phenomenon in early wheats. Heading date appeared negative correlations with test weight and with number of culm before winter, but showed positive correlation with number of kernels/spike.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.11-15
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• 1977

Natural infection of purple stain seemed to be higher in early maturing lines comparing to late maturing group. It was positively correlated with length of the period from flowering to maturity and significantly associated with weather conditions during the maturing period.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.407-413
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• 2023

This experiment was carried out to breed a medium maturing variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, Rural Development Administration (RDA), Cheonan from 2019 to 2020. An Italian ryegrass variety, IR 604 is a tetraploid variety with green in leaf color and has half-erect growth habit in late autumn and erect growth habit in early spring, IR 604 was on May 17 in heading date as a medium maturing variety. Also, IR 604 was longer by 11 cm in flag leaf length and longer by 1.3 cm in plant height than those of the control variety, Kowinner, respectively. IR 604 was also thicker by 1.0 mm in stem thickness and strong in winter hardness. Dry matter (DM) yield (11,036 kg/ha) of IR 604 was 16.6% higher than that of Kowinner. Total digestible nutrient (TDN), crude protein (CP) and relative feed value (RFV) of IR 604 were 60.4, 13.8% and 100.6 which are 1.4, 3.3%, 7.7 higher than those of Kowinner, respectively. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) of IR 604 were 35.5 and 56.7% which are 1.3 and 3.6% lower than those of Kowinner, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.4
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• pp.339-346
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• 1999

This experiment was carried out to determine harvest date and cultivar effects on the agronomic characteristics, forage yield, and quality of fall sown oat (Avena sativa L.) at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon from August to November 1993. The experiment was arranged in a split plot design with three replications. The main plots were consisted of the harvesting dates, suchas early (11 October), mid(21 October), and late(1 November), the subplots were consisted of different maturities of oat cultivars, such as 'West', 'Cayuse' and 'Magnum'. The first heading date of an early maturing culivar, West, was observed on 10 October, and the heading increased up to 30% at the late harvesting date. The average dry matter (DM) content of oat cultivars increased significantly from 12.8 to 15.9% as the growing stage progressed(p<0.01). The average dry matter percentage of West, Cayuse, and Magnum was 15.4, 13.4, and 13.5%, respectively. The crude protein (CP) content of oat cultivars decreased significantly from 20.1 to 13.3% as the harvesting date was delayed(p<0.01), and the CP contents of midseason and late maturing cultivars, Cayuse and Magnum, respectively, were significantly higher than that of an early maturing cultivar West (p<0.01). The mid harvesting date showed the highest acid detergent fiber(ADF) and neutral detergent fiber (NDF) contents than the other harvesting dates, and an early maturing cultivar West had higher ADF and NDF contents than the midseason and late maturing cultivars, Cayuse and Magnum, respectively. The in vitro dry matter digestibility(IVDMD) of oat cultivar West decreased as the harvesting date was delayed, but that of Cayuse and Magnum decreased only by the mid harvesting date. Cayuse and Magnum showed 3~4% higher digestibility than West. The correlation coefficient between IVDMD and ADF content was -0.86. The average dry matter yield of oat cultivars increased from 2,901 to 5,901kg/ha as the harvesting date was delayed(p<0.01), but no significant difference was found among oat cultivars. The corrdelation coefficient between DM yield and gorwing degree days(GDD) was +0.86. The results of this study indicate that a delay in harvesting date would be recommendable for the increase of dry matter yield when fall-sown oat is grown. Especially, the DM yield of the midseason and late maturing cultivars, Cayuse and Magnum, respectively, can be increased without much change of forage quality although the harvesting date are delayed.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.170-180
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• 1987

This study was undertaken to determine the effects of HCG and trout pitutary on sexual maturation and ovulation in the Korean loach, Misgurnus anguillicaudatus. Sexual maturation was observed in the fish treated with 250＋125 IU HCG within 2-4 days following injections. Total ovary weight and GSI were significantly greater in the hormone-treated fish than in the control fish. Furthermore, in the hormone-treated fish body weight increased by about 4-9 percent in 2 days. The water content of the ovulated eggs of the fish treated with 250＋125 IU HCG was also greater than that in the control. Changes in both macroscopic & microscopic appearnce of Korean loach ovaries are describled, as well as changes in the gonadosomatic index. Oocytes pass through seven cytologically changes in the relative stages. By examining these stages, it was found that oogenesis occures in two broad phases. The previtellogenic phasebegins as a new oogonia continues to arise following spawning. These rapidly develop into early perinucleolus oocytes, which in turn develop into resting stage oocytes. Most oocytes remain in this stage when they develop into late perinucleolus oocytes. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. Shortly before spawning the final hyaline stage of developing is reached. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.145-150
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• 1997

To find out the optimum fertilizer level for onion, early maturing cultivar Fechongjoseng, experiment with four fertilizer levels was conducted of the field of the paddy and upland in Muan and Changyeong from Sep.1993 to Feb.1995. The yield character of onion was higher and rate of the rottenness was lowest under the treatment of $N-P_2O_5-K_2O$=28-9.5-23Kg/10a in the soil of paddy and upland field of Muan area. But the onion yield was excellent and rate of the rottenness was lowest under the treatments, $N-P_2O_5-K_2O$=21-19-17.3Kg/10a, in the soil of paddy field and $N-P_2O_5-K_2O$=28-9.5-23Kg/10a, in the soil of upland field of Changyeong area.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.310-310
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• 2017

'Gawaji 1', an early maturing and low amylose content rice variety adaptable to double cropping system with barley as later winter crop., was developed by the crop breeding team of Crop Research Division, GARES, Hwaseong, Korea in 2016. 'Gawaji 1' was derived from a cross between 'Baegjinju' and 'Sangmibyeo' in 2004. This variety had heading date of August 4 in Gyeonggi Province. It had a semi-elect plant type and resistance to lodging with strong culm. Its culm length was 67 cm. This variety had 15 tillers per hill and 104 spikelets per panicle. It was medium grain variety showing 1,000 grain weight of brown rice of 19.3g. Its protein contents of milled rice was 8.2% which was lower than 'Baegjinju'. Its milling ratio was 75.5% which was higher than 'Baegjinju'. The yield of milled rice was 5.0 MT/ha under the ordinary culture of the local adaptability test in 3 areas of Gyeonggi Province for three years. 'Gawaji1' is highly adaptable to Gyeonggi Province, especially to northern region of Han River.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.452-461
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• 1982

Average yield of wheat and barley cultivars has been increased 3 percent every year by varietal improvement. The major characteristic changes of those improved cultivars were the early maturing and lodging resistance using dwarf genes, 70-90cm of culm length appearances, under the heavy fertilizer application. Looking back the cultural practices of wheat and barley for the last 20 years, the introduction of early maturing and lodging resistance cultivars around 1970 brought the changes of seeding rate from 65kg to 130- 200kg per hector and the tillering increased by heavy fertilizer. The utilization of livestock and man power for preparation of seedbed were gradually disappeared by increasing agricultural mechanization. The narrow-spaced seeding $(40cm {\times} l8cm)$ and drill seeding $(20cm {\times} 5cm)$ in upland, broadcasting or drilling on high ridge $(120cm {\times} 90cm)$ with the power-toller and whole area broadcasting in paddy field were improved as the main cultural method. The use of agricultural machineries reduced the labour consumption of 940 man hours to 180 man hours per hector from seeding to harvest.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.239-250
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• 2002

Evaluation works of oat in mixture with rye on forage yield have not been reported. The objective of this study was to determine yield and quality of forage mixture as affected by maturity of rye cultivar and oat-rye seeding rate at Suweon from 1999 to 2000. The experiment was arranged in a split plot design with three replications. Main plots consisted of maturity of rye. such as early(cv. Koolgrazer) and late(cv. Kodiak)maturing cultivars. Sub-plots consisted of seeding rate (T1: Oat 2000 and rye 0kg/ha, Ts: Oat 150 and rye 40kg/ha, T3: Oat100 and rye 80kg/ha, T4: Oat50 and rye 120kg/ha. and T5: Oat0 and rye 160kg/ha). Crude protein(CP) content of oat-rye mixture harvested in the fall was not influenced by maturity of rye cultivar, but that of oat-rye mixture was increased from 13.6 to 19.3% as the seeding rate of rye increased(P<0.05), however, maturity of rye cultivar significantly affected CP content of oat-rye mixture in the spring(P<0.01). Acid detergent fiber(ADF) content of oat-rye mixture harvested in the spring was not significantly affected by rye cultivar, but the ADF was decreased from 27.8 to 20.7% as the seeding rate of rye increased(P$<$0.01). When rye was harveste in the spring, ADF content of late maturing cultivar 'Kodiak' was shown as 28.0%. This was lower than that of early maturing cultivar 'Koolgrazer' which was shown as 35.8%(P$<$0.01). Among treatments, neutral detergent fiber(NDF) and in vitro dry matter digestibility(IVDMD) of oat-rye mixture showed a similar trend made on ADF. In this experiment, the highest forage yield (12.356kg/ha) was obtained from early maturing rye cultivar and seeding rates of 100kg/ha of oat and 80kg/ha of rye mixture. A significant interaction between maturity of rye cultivar and seeding rate was found(P$<$0.01). The above results indicate that an early maturing rye cultivar at the seeding rate of 100kd/ha in mixtures with 80kg/ha of oat could be recommended as a succeeding cropping system after corn for silage.