• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.93-104
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• 2010

This study was conducted screening of the population densities of fungal pathogens and insect and observed the disease symptoms on the organic sweet corn seed producing field from 2008 to 2009. The dissemination spores, Alternaria sp., Cladosporium sp., Helminthosporium sp., Pyricularia sp., Collectotrichum sp., and Bipolaris sp., were detected and the three fungal spores from the front were observed for whole growth stage. Seed and seedling diseases were shown as the rotted seed and damping-off seedling caused by Penicillium sp. and Rhizoctonia sp.. The larva of Black cutworm cut down the root crown of seedlings. The damaged plants were ranged from 14% to 16%. On the Oriental corn borer, the population densities and the percentage of damaged plants were showed a low difference between two sweet corn varieties. The population densities of Oriental corn borer were scored as from 3.5 to 20.5 in 2008 and from 0.5 to 6 in 2009. Also the percentage of damaged plants were significantly increased until harvesting stage and was recorded from 7.5% to 21% in 2008 and from 1% to 46% in 2009. On the Corn leaf blight, the percentage of diseased plant were scored from 7% to 34% in 2008. The first occurrence of date was after June 18, and the percentage of diseased plant was continuously increased after August 21 and the values of diseased plants was ranged from 56% to 69% in 2009. On common smut, the percentage of diseased plant was recorded from 5% to 15% in 2008, and the first occurrence date were delayed as 17 days (July 17) and were showed less than 8% of diseased plants in 2009. Corn Southern Leaf spot was scored as average 11% at early stage and showed high score as 62% at September 19 in 2008. In 2009, the first occurrence date were advanced about 20 days (after June 8), and continuously increased up to 86% in 2009.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.34-41
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• 1994

This experiment was carried out to select the $Sorghum{\times}Sudangrass$ hybrid of high productivity suited for soiling, and growth characteristics and productivity of 9 cultivars of introduced $Sorghum{\times}Sudangrass$ hybrids have been evaluated at the experimental forage field, College of Natural Science of Kon-Kuk university in Chungju over three years. The results obtained are summarized as follows : 1. NC855, Sordan79 and T. E haygrazer were taller than the other varieties as range from 209cm to 213cm. while Supergrazer was the shortest type as 173cm. Among the nine varieties used, NC855 and Pioneer 988 were classified as early maturing varieties, but G83F, FP5 and Supergrazer were classified as lately maturing varieties. 2. The stem diameter of Supergnzer and Sordan79 were thicker than the other varieties, while NC855, Garst757 and FP5 were thin. 3. The tillers of $Sorghum{\times}Sudangrass$ hybrids were ranged from 3.1 to 4.0 and NC855 and FP5 had 4.0 tillers per plant. The dead stubble of Sordan79 was the lowest as 4.0 percentage, while Supergrazer was the highest as 9.8 percentage(P<0.05). 4. GW9110G and T. E haygrazer were susceptible to lodging(P

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.292-298
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• 2009

A new rice cultivar "Keumo 3" was developed for adopting under double cropping system with after or before cash crop cultivation. It was selected from the cross-combination between YR17202 $F_2$/Shinkeumobyeo//YR15727-B-B-B-102. The parent, YR17202 $F_2$ individual plant, was used for tolerance to lodging, it derived from a cross between Nonganbyeo/Shinkeumobyeo. Nonganbyeo is well known to lodging tolerance cultivar, as well as biotic stress, because it was developed by crossing with Tongil type. And the YR15727-B-B-B-102 line used as another parent with short growth duration, likewise highly resistance to rice blast disease. The pedigree derived from the cross-combination YR17202 $F_2$/Shinkeumobyeo//YR15727-B-B-B-102 were generated to $F_7$, and a best line among them named as Milyang 201. After a series of yield trials, including local adaptability test conducted throughout the peninsular of Korea, Milyang 201 was registered with the name of "Keumo 3" in 2005. The cultivar belongs to a early maturing group and heads 4 days earlier than Keumobyeo, a standard cultivar. It has short culm, and less spikelet number per panicle than Keumobyeo. However, its milled rice yield grown under extremely late transplanting time, 10. July, over the 3 local sites for 2003-2005 years, averaged 4,48 MT/ha, which is 6% higher than the standard, Keumobyeo. "Keumo 3" has showed a durable resistance to leaf blast disease during fourteen blast nurseries screening covered from south to north in Korea for 2003-2007 years. And it was confirmed harbours pi-zt, a durable blast resistance gene. Moreover it was incompatible with 19 blast isolates under artificial inoculation, except one isolate, K1101. Additionally, "Keumo 3" exhibits resistance to $K_1$, $K_2$ and $K_3$ of bacterial blight pathogen, as well as strip virus disease resistance, and moderate resistance to dwarf virus disease. Consequently, the new rice cultivar "Keumo 3" would be well adopted where a bio stress makes a big problem annually.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.529-532
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• 2008

Manna is a new japonica rice cultivar developed from the cross between Iksan438 and Ilmibyeo by the rice breeding team of Department of Rice and Winter Cereal Crop, RDA, in 2005. This cultivar has a short grain shape and about 97 days growth duration from late transplanting to harvesting under Korean climatic conditions. It is resistant to lodging with average 70 cm of culm length. The milled kernels of Manna are translucent with non-glutinous endosperm. It has about 19% amylose content and good palatability of cooked rice compared with Geumobyeo. This cultivar shows resistance to leaf blast and neck blast but susceptibility to bacterial blight and stripe virus diseases. The milled rice yield potential of Manna is about 5.05 MT/ha under the late transplanting cultivation. Manna would be adaptable for the middle and Honam plain of Korea.