• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.134-144
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• 2003

A rhizobacterium Pseudomonas cholororaphis O6 produced several secondary metabolites, such as phenazines, protease, and HCN that may be involved in inhibition of the growth of phytopathogenic fungi. In field study, P. chlororaphis O6 treatment on wheat seed suppressed root rot disease caused by Fusarium culmorum. The major organic acids of cucumber root exudates were fumaric acid, malic acid, benzoic acid, and succinic acid. Glucose and fructose were major monosaccharides in cucumber root exudates. The total amount of organic acids was ten times higher than that of the sugars. P. chlororaphis O6 grew well on cucumber root exudates. The dctA gene of P. chlororaphis O6 consisted of a 1,335 bp open reading frame with a deduced amino acid sequence of 444 residues, corresponding to a molecular size of about 47 kD and pI 8.2. The deduced dctA sequence has ten putative transmembrane domains, as expected of a membrane-embedded protein. Our results indicated that organic acids in cucumber root exudates may play an important role in providing nutrient source for root colonization of biological control bacteria, and the dctA gene of P. chlororaphis O6 may be an important bacterial trait that is involved in utilization of root exudates.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.130-136
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• 2009

"Hanbaek", a white winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross "Shan7859/Keumkang"//"Guamuehill" during 1996. "Hanbaek" was evaluated as "Iksan314" in Advanced Yield Trial Test in 2005. It was tested in the regional yield trial between 2006 and 2008. "Hanbaek" is an awned, semi-dwarf and hard winter wheat, similar to "Keumkang" (check cultivar). The heading and maturing date of "Hanbaek" were similar to that of "Keumkang". Culm and spike length of "Hanbaek" were 89 cm and 9.0 cm, which longer culm length and spike length than "Keumkang" (80 cm and 7.9 cm, respectively). "Hanbaek" had lower test weight (797 g) and higher 1,000-grain weight (47.7 g) than "Keumkang" (813 g and 44.9 g, respectively). "Hanbaek" showed resistance to winter hardiness and susceptible to pre-harvest sprouting, which lower withering rate on the high ridge (4.4%) and higher rate of pre-harvest sprouting (47.9%) than "Keumkang" (21.9% and 30.4%, respectively). "Hanbaek" had similar flour yield (74.4%) to "Keumkang" (74.1%) and higher ash content (0.45%) than "Keumkang" (0.42%). "Hanbaek" showed lower lightness (89.13) and similar redness and yellowness (-0.87 and 10.93) in flour color than "Keumkang" (90.02, -1.23 and 9.28, respectively). It showed similar protein content (12.8%) SDS-sedimentation volume (63.0 ml) and gluten content (10.8%) to those of "Keumkang" (11.9%, 62.3 ml and 10.2%, respectively). It showed lower water absorption (59.6%) and mixing time (3.8 min) in mixograph and higher fermentation volume (1,350 ml) than those of "Keumkang" (60.6%, 4.7 min and 1,290 ml, respectively). Amylose content and pasting properties of "Hanbaek " were similar to those of "Keumkang". "Hanbaek" showed same compositions in high molecular weight glutenin subunits (HMW-GS, 2*, 13+16, 2+12), granule bound starch synthase (Wx-A1a, Wx-B1a, and Wx-D1a) and puroindolines (Pina-D1a/Pinb-D1b) compared to "Keumkang". "Hanbaek" showed lower hardness (4.22N) and similar springiness and cohesiveness of cooked noodles (0.94 and 0.63) to those of "Keumkang" (4.65N, 0.93 and 0.64, respectively). Average yield of "Hanbaek" in the regional adaptation yield trial was 5.98 MT/ha in upland and 5.05 MT/ha in paddy field, which was 8% and 6% higher than those of "Keumkang" (5.55 MT/ha and 4.77 MT/ha, respectively). "Hanbaek" would be suitable for the area above the daily minimum temperature of $-10^{\circ}C$ in January in Korean peninsula.