• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2010.04a
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• pp.375-379
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• 2010

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.256-266
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• 1993

History , achievement and future of direct-wet-rice-seeding technique in Korea and problems encountered in on-farming research were introduced. Some farmers are very eager to lower production cost and save labor. Their effort results in several direct-wet-seeding methods and seeding machines. The design problems and improvement points related to the direct -wet-rice-seeding machines were drawn out of field test.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2004.11a
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• pp.58-61
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• 2004

• Proceedings of the Korean Society of Crop Science Conference
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• 1995.05a
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• pp.52-53
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• 1995

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.407-415
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• 2009

To investigate the effects of seeding date, nursery days and plug cell size on seedling growth and quality of waxy corn. This study was carried out in the field of the National Institute of Crop Science in 2007. Varieties used were two waxy corn hybrids cvs. Chalok# 1 and Chalok# 4. The plant height, number of leaves and dry weight of waxy corn seedlings were significantly affected by seeding dates and plug cell size, while no differences between varieties. The growth of seedlings was faster in March 14 seeding than in May 8 and July 4 seedings. Based on plant height, March 14 seeding, May 8 seeding and July 3 seeding reached suitable size for transplanting after 30 days (21.6cm), 15 days (25.5~26.9cm) and 10 days (21.6~24.0cm) in the nursery, respectively. Seedlings of March 14 seedling and May 8 and July 3 seeding reached suitable number of leaves i,e. 2~3 leaves, 15~20 days after seeding on March 14 and 10 days after seeding on May 8 and July 3. Dry weights of 30 days seedling for March 14 seeding, 20 days seedling for May 8 seeding and 15 days seedling for July 3 seeding were 0.43g, 0.57~0.67g and 0.53g, respectively, and the dry weight of seedlings increased by 2~3 folds at the later nursery days. The suitable nursery days of waxy corn were 20 days on March 14 seeding and 10~15 days on May 8 or July 3 seeding.

• Plant Breeding and Biotechnology
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• v.2 no.3
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• pp.289-300
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• 2014

A tissue-specific and developmentally expressed gene was isolated from Chinese cabbage (Brassica rapa L. ssp. pekinensis), designated BrREF (B. rapa Rubber elongation factor). BrREF transcripts were expressed at high levels in seedlings and at low levels in flower buds and roots. To study the activity of this promoter, the 2.2 kb upstream sequence of BrREF gene was fused to a β-glucuronidase (GUS) reporter gene and was introduced into Arabidopsis thaliana and B. napus by Agrobacterium-mediated transformation. Strong expression of GUS driven by the BrREF promoter was detected in the cotyledons and hypocotyls of transgenic plant seedlings, but GUS expression was weak in roots, excluding the root tips. GUS expression in the cotyledons and hypocotyls decreased dramatically as the seedlings matured and was not detected in the tissues of mature plants. During floral development, GUS expression was observed in immature anthers. These findings suggest that the BrREF promoter can modulate the tissue-specific and developmental expression of gene at the early stages of growth and development.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.90-94
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• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.18-22
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• 2002

Diseases occurrence of hydroponic culture was less than that of soil culture, especially gummy stem blight, which was 39.9-53.3% of infection rate at soil culture, was not almost observed at hydroponic culture. Development of fermented fruit was higher at Shintozoa, Hongtozoa and self-rooting seedling in order at soil cultured but critically dropped at hydroponic culture without rootstock sort. Therefore proper moisture management at root zone can decrease the development of fermented fruit.

• Journal of Plant Biology
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• v.27 no.4
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• pp.241-251
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• 1984

The present study investigated the effects of triacontanol (TRIA) on plant growth and peroxisomal enzyme activities in radish seedlings. The optimum concentration of TRIA with respect to radish seedling bioassay was decided to 1.0mg $1^{-1}$. In comparison to untreated controls (including Tween 20 treatment), 1.0mg $1^{-1}$ TRIA treatment caused an increase in seed germination rate and root growth, but no stimulation in hypocotyl growth. Chlorophyll accumulation in cotyledon during carly development stage increased rapidly, and degradation of chlorophyll in later stage due to the cotyledon senesence was noticeably retarded. Increase of soluble protein content in cotyledon at early period of development was observed. Isocitrate lyase and catalase activity was not significantly different in both the treated and the untreated plants. But, glycolate oxidase activity was inhibited by TRIA down to 20% against controls. Also, the increase of the activity of peroxidase, a leaf-senescence marker enzyme, was continuously retarded over control for 8 days of development. Based on above results, TRIA was found to be active in both the growth and the peroxisomal enzyme activities of radish seedlings.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.1
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• pp.20-25
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• 2020

Spatial simulation of crop growth often requires application of management conditions to each cell. In particular, it is of great importance to determine the temperature conditions during the nursery period for rice seedlings, which would affect heading date projections. The objective of this study was to determine the value of TMPSB, which is the parameter of ORYZA2000 model to represent temperature increase under a plastic tunnel during the rice seedling periods. Candidate values of TMPSB including 0℃, 2℃, 5℃, 7℃ and 9℃ were used to simulate rice growth and yield. Planting dates were set from mid-April to mid-June. The simulations were performed at four sites including Cheorwon, Suwon, Seosan, and Gwangju where climate conditions at rice fields common in Korea can be represented. It was found that the TMPSB values of 0℃ and 2℃ resulted in a large variation of heading date due to low temperature occurred in mid-April. When the TMPSB value was >7℃, the variation of heading date was relatively small. Still, the TMPSB value of 5℃ resulted in the least variation of heading date for all the planting dates. Our results suggested that the TMPSB value of 5℃ would help reasonable assessment of climate change impact on rice production when high resolution gridded weather data are used as inputs to ORYZA2000 model over South Korea.