• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.2
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• pp.146-156
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• 1988

This study was carried out to investigate the change of endosperm substance and seedling growth in rice seedlings for machine transplanting with use of two rice varieties, which Samgangbyeo (Indica${\times}$Japonica) and Dogjinbyeo (Japonica) were sown on May 8 with five levels of seeding density. 1. The total dry matter weight, leaf area, length of the longest root, number and length of new roots were negatively correlated with seeding density, and the plant height had the similar tendency to them from 20 days after sowing(DAS). 2. The rooting ability was negatively correlated with seeding density and decreased from 35 DAS in Dongjinbyeo. 3. The endosperm substance were exhausted at 25 to 30 DAS in Samgangbyeo and at 25 DAS in Dongjinbyeo. 4. The leaf area was more useful than the ratio of plant height to dry matter weight for judging the constitution of seedlings. 5. The reducing sugar contents in the endosperm were the greatest among parts of rice seedlings followed by leaf and root. The contents in leaf, root and endosperm reached maximal at 10 DAS, and varied with plant parts, seedling growth and varieties in different levels of seeding density. 6. The protein contents in leaf and root of rice seedlings became decreased with seedling growth., and were minimal values at 15 DAS. The content in endosperm was decreased soon after seeding, and minimal at 4 DAS with showing some fluctuation of protein content after then.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.29-33
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• 1984

From June 28th to July 17th in 1985, this study was performed to obtain the information of the fresh corn forage production through the spraying hydrophonics in summer. The experiments were conducted in vinyl house on Kyungpook University's Experimental Station. The results obtained were as follows: It was suggested that the treatment of soaking for 24 hrs and followed by the pretreatment for 48 hrs was better than other treatments. Seed cost for the production of 1 kg fresh forage was the most inexpensive at the seeding rate of 450 g per $30{\times}60cm$ tray than other seeding rates. Application of 1000 times diluted Hyponex solution (1000X Hyponex) or 300 times diluted Yogen solution (300X Yogen) one time per day resulted in the heavier fresh weight than the other treatments. Treatments of 300X Yogen and 500X Yogen gave the better fresh weight in one application per two days and per three days, respectively. But, this method was not useful in summer because the lowest seed cost for the production 1kg fresh forage was 73Won, and collection of the fresh forage from the mountain range was easy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.201-210
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• 1990

This study was carried out to determine the effect of mixture of hymexazole and metalaxyl(Tachigarace) on the growth and reducing low temperature injury in rice seedlings. The amount of mixture of hymexazole and metalaxyl (Tachigarace) applied to reduce low temperature injury was 0, 9, 18 and 36mgr per pot (5${\times}$15${\times}$10cm) by soil incorperation befor sowing. Aging seedling was investigated on the growth responses by the application of 0.36gr mixture of hymexazole and metalaxyl (Tachigarace) per tray (30${\times}$60${\times}$3cm) after cutting of leaf at 35 day-old seedling. Rice seedlings treated with mixture of hymexazole and metalaxyl (Tachigarace) were better in the growth of top and roots, dry weight, erecting and rooting abilities than untreated seedlings. The effective amount of mixture of hymexazole and metalaxyl (Tachigarace) to increase erecting and rooting abilities was 18 mgr per pot. Under low temperature treatment, 12$^{\circ}C$, the leaf discoloration and dead leaf percent of rice seedlings were markedly decreased in the seedlings treated with mixture of hymexazole and metalaxyl (Tachigarace) as compared with untreated seedlings. The more amount of mixture of hymexazole and metalaxyl (Tachigarace) upto 36mgr per pot, the more effective on the low temperature injury in the seedling. The effect of mixture of hymexazole and metalaxyl (Tachigarace) to reduce low temperature damage in rice seedlings was mainly due to decreasing less physiological activities on the expanding leaf area and rooting, transpiration, stomatal diffusion and chlorophyll content of the leaves and oxygen consumption of the roots. Plant height, top dry weight and leaf area of aging seedlings were increased with mixture of hymexazole and metalaxyl (Tachigarace) treatment and leaf cutting as compared with untreated seedling and intact leaf, respectively. The ratio of missing hill of aging seedling was increased with increasing the period of growing seedling and was decreased due to leaf cutting, whereas the effect of mixture of hymexazole and metalaxyl (Tachigarace) application was not observed. Rooting ability of aging seedlings was decreased with lengthening of the period of raised seedling and was increased with mixture of hymexazole and metalaxyl (Tachigarace) treatment and leaf cutting.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.240-255
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• 2012

The objectives of this study were to investigate the levels of phytotoxicity of rice varieties to HPPD (4-hydroxy phenylpyruvate dioxygenase)-inhibiting herbicides known for their efficiency to control the sulfonylureas-resistant weed species：mestrione, benzobicyclone, and tefuryltrione. The twenty-six rice varieties (8-Japonica ${\times}$ Indica-type varieties and 18-Japonica-type varieties) were grown for 25 days on seedling trays and then transplanted to paddy rice fields followed by herbicide treatment i.e. standard and double doses of there respective herbicides at 5, 10, and 15 days after transplanting. Although mestrione, benzobicyclone and tefuryltrione are all HPPD-inhibiting herbicides, the phytotoxicity symptoms of the different rice varieties based on the timing of application and doses of the herbicides were significantly different. The Japonica ${\times}$ Indica-type varieties showed much more phytotoxicity symptoms than Japonica-type varieties in all applied herbicides. Increasing herbicidal doses of mesotrione, and an earlier application of and increasing herbicidal doses of benzobicyclon caused severe phytotoxicity symptoms. On the other hand, phytotoxicity due to tefuryltrione did not exhibit significant differences between rice varieties in either the timing of application or dose of the herbicide. Regardless of timing of application and dose of the herbicides, Hangangchalbyeo-1, Hyangmibyeo-1 and high-yield rice varieties such as Namcheonbyeo, Dasanbyeo, Areumbyeo, and Hanareumbyeo, which belong to the Japonica ${\times}$ Indica-type varieties, showed 5 to 8 levels of phytotoxicity symptoms including albinism, browning, detached leaf, and necrosis to mesotrione and benzobicyclon whereas only 1 to 3 levels of phytotoxicity symptoms (chlorosis, albinism, and browning) were seen with to tefuryltrione application. The Japonica-type varieties exhibited only slight phytotoxicity symptoms (1~2 levels) in conformity with the timing of application and doses of the herbicides. However, there were significant differences among the Japonica-type rice varieties, depending on the type of herbicide. Thirteen-Japonica type rice varieties were sensitive to benzobicyclone while 4-Japonica-type and 7-Japonica-type varieties showed phytotoxicity symptoms such as chlorosis and albinism with mestrione and tefuryltrione application, respectively. Therefore, we suggest that the combined-type herbicides including mestrione, benzobicyclone and tefuryltrione should be rejected in paddy fields where rice is grown for either human consumption (functional or processed rice) or livestock feed because of severe phytotoxicity symptoms on the various rice varieties seen regardless of the timing of application and doses of the herbicides.