• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.241-251
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• 2011

Bacterial blight(BB) caused by Xanthomonas oryzae pv. oryzae(Xoo) is one of the most economically destructive bacterial diseases of rice in worldwide. Utilization of resistant cultivars carrying resistant gene(s) is relatively an effect method to control this disease. About 34 resistant genes for BB resistance have been identified in many countries. Among them, Xa1 and Xa3 genes against bacterial blight have been incorporated into improved korean japonica rice varieties. Now, Ilmi carrying Xa1 gene and severial cultivars carrying Xa3 gene are widely grown in our country. In recent year, xa5, Xa21 and Xa23 genes are using in rice breeding programs for japonica resistant cultivars to bacterial blight. Resistant cultivars incorporated with a diverse single gene and two, three, or the more major gene necessite in the future.

• Research in Plant Disease
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• v.10 no.1
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• pp.73-77
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• 2004

The gene analysis of resistance in rice cultivars, Daeanbyeo, Hwasunchalbyeo, Daejinbyeo, Naepungbyeo, Hwajinbyeo and Surabyeo to strains of Xanthomonas oryzae pv. oryzae was studied. F$_1$ plants and F$_2$ populations from the crosses between six cultivars and near isogenic lines carrying the single bacterial blight(BB) resistance gene were analyzed using Korean and Japanese BB races. Daeanbyeo, Hwasunchalbyeo, Daejinbyeo, Naepungbyeo, Hwajinbyeo and Surabyeo are alleic with IRBB101 but are non-alleic with IRBB104 and IRBB105. The allelic tests indicated that Daeanbyeo, Hwasunchalbyeo, Daejinbyeo, Naepungbyeo, Hwajinbyeo and Surabyeo have the Xal gene for resistance.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.503-506
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• 2011

In order to analyze the resistant gene to Xanthomonas oryzae pv. oryzae in Korean native rices. Six Korean native rice varieties were crossed with IR-BB 101 contains Xa1 resistant gene and inoculated Japanese isolates IA(T7174). Cheonggunbyeo has Xa1 resistant gene only, and Yukseongjaerae, Agukdo, Heukpi and Icheon7ilchal have Xa1 and another one dominant gene. Ginggaragshare has Xa1 and another two dominant genes and two of those genes concerned complementary interaction against Japanese isolates IA(T7174).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.124-133
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• 2011

Bacterial blight (BB), cuased by the vascular pathogen Xanthomonas oryzae pv. oryzae, is one of the major threats in rice fields worldwide. In Korea, two resistance genes against BB, Xa1 and Xa3 had been intensively used for developing high quality japonica rice cultivars. Those traditional resistance sources have being rapidly ified by the adopting of BB pathogen through mutations of the corresponding avr-genes, such as K3a exhibiting high compatibility to both Xa1 and Xa3. To expanding genetic resource against BB in Korea, the Suweon506, an introgression line between a Korean japonica cultivar, Hwaseong and a wild relative, Oryza minuta, was be subjected for genetic analysis owing to the BB resistance. Through association analyses between the pathotyping and genotyping results for each $F_2$ progenies, derived from a cross between Suweon506 and a Tongil type cultivar, Milyang23, a major resistant dominant gene is localized on the subterminal region of rice chromosome 4, where at least three BB resistancde genes, Xa1, Xa2, and Xa22, were reported previously.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.92-100
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• 2009

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in $M_1$ generation and chlorophyll mutations were observed in $M_3$ generation. Germination rate and seedling height decreased as the increase of SA concentration in $M_1$ generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in $M_3$ generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in $M_3$ generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in $M_3$ generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.244-251
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• 2009

This study was carried out to identify useful single gene and gene combination resistant to K1, K2, K3 and 24 bacterial blight(BB) isolates (including K3a, HB01009) breaking down Xa3 gene. Xa3, Xa4, xa5 and Xa7 genes were resistant to K1, K2, K3 of bacterial blight pathogen. Against 24 BB isolates breaking down Xa3 gene, Xa1, Xa2, xa8, Xa10, Xa11, xa13 genes were susceptible, whereas Xa4 gene was moderately resistant and xa5 and Xa21 genes were resistant. IRBB7 having Xa7 gene showed resistance responding to 24 BB isolates, whereas IRBB107 carrying Xa7 gene was susceptible to 10 BB isolates and moderately resistant to 14 BB isolates. Near-isogenic lines (NILs) of Toyonishiki and IR24, both possessing Xa7 gene, showed different resistance response against 24 BB isolates according to genetic background. Xa3+xa5, Xa4+xa5, Xa4+xa13, Xa4+Xa21, xa5+xa13, xa5+Xa21, xa13+Xa21, Xa4+xa5+xa13, Xa4+xa5+Xa21, Xa4+xa13+Xa21, xa5+xa13+Xa21, and Xa4+xa5+xa13+Xa21 were resistant to K1, K2, K3 and 24 isolates breaking down Xa3 gene. When Xa3 and xa13 genes were combined with xa5, Xa4, Xa21, resistance response was enhanced compared with single gene lines containg only Xa3 or xa13. Similarly, when Xa4 gene was combined with xa5 and Xa21, resistance response was improved by the gene combination effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.89-99
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• 2007

To develop durable and stable breeding strategies far the control of rice bacterial blight (BB) disease, the near-isogenic lines (NILs) with diverse resistance genes to BB isolates were evaluated in plant at three different growth stages using four Korean ($K_1,\;K_2,\;K_3,\;K_{3a}$) and three Japanese isolates (I, II, III). The resistance of the NILs to seven BB isolates tended to increase with plant aging. At the seedling stage, the NILs with single resistance genes were mostly resistant to $K_1$ race but they showed partial or no resistance to other isolates. A NILs (IRBB5) possessing xa5 had full resistance to the four Korean isolates, illustrating that it is a useful source to give enhancement to Korean breeding program. At the maximum tillering stage, resistance of NILs to $K_2,\;K_3$, I and II isolates considerably increased while resistance to $K_1,\;K_{3a}$ and III were similar to those of seedling stage. NILs with resistance gene of Xa4, xa5 and Xa7 proved to be the most stable to BB isolates at the maximum tillering stage. At the heading stage, most resistance genes of NILs were effective against BB isolates, and xa5 showed the consistent resistance to all the BB isolates including $K_{3a}$ and III isolates, demonstrating that resistance genes of Xa4, xa5 and Xa7 can be used either alone or combined to enhance resistance to BB disease in Korea.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.40-47
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• 2005

In order to develop a multi-microbial biofungicide against several important plant pathogenic fungi, strains were isolated from the phtophthora blight suppressive red-pepper field soil of Gyeongsangbuk-do, Korea. Strains AY1, AY6, AB1, BB2 and F4, which had strong antagonistic ability against Phytophthota capsici and Fusarium oxysporum, were selected for their involvement with strains of biocontrol fungicide. There were no antagonism among the selected strains and were compatible for making the biofungicide. Their antagonistic mechanisms, except for strain BB2, were an antibiosis by the production of antibiotic, while BB2 produced not only an antibiotic but also cellulase as an antagonistic mechanism against blight causing P. capsici. They were identified as Halobacterium sp. AB1, Xenorhadus sp. AY1, Bacillus sp. AY6, Bacillus sp. BB2, Zymomonas sp. F4 by various cultural, biochemical test and $Biolog^{TM}$ System 4.0. The highest levels of antifungal antibiotic could be produced after 48 hrs of incubation under the optimal medium which were 0.1% galactose, 0.1% $NaNO_2$, 5 mM $Na_2{\cdot}HPO_4$ (pH 5.5). The cultured multi-microbial biofungicide showed strong biocontrol activity against bacterial wilt disease and fusarium wilt disease in cucumber and tomato fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.151-155
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• 2005

This study was carried out to get information for diversifying of resistant genes to bacterial blight (BB) in Japonica cultivar breeding programs. TWo hundred nine rice varieties were tested for qualitive resistance to four races of BB; HB9101 isolate for race K1, HB9102 isolate for race K2, HB9103 isolate for race K3, and HB01001 isolate for race K3a. Two hundred nine rice varieties were divided into five groups according to their race reaction. Fourteen Tongil-type varieties and ninetyseven Japonica varieties showed susceptible reaction to four races; Kl, K2, K3 and K3a. Thirteen Tongil-type varieties and thirty-one Japonica varieties were resistant to only one race; K1. Nine Tongil-type varieties and one Japonica variety were resistant to two races; K1 and K2. One Tongil-type variety and twenty-eight Japonica varieties were resistant to the three races; K1, K2, and K3. Fourteen Tongil-type varieties and one Japonica variety were resistant to four races; K1, K2, K3, and K3a. A number of Tongil-type varieties showed broad spectrum resistance to four races, while a number of Japonica varieties showed broad spectrum resistance to three races; K1, K2, and K3.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.139-141
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• 2003

Disease severity, percent ripened grains, and yield were investigated in the seven mixtures by using near-isogenic lines having different resistant gene(s) to bacterial blight(BB) of rice. The seven mixtures including the four pure stands were inoculated with a 1:1:1 mixture of races $K_1$, $K_2$, and $K_3$ of BB. Among the seven mixtures-ML01, ML02, ML03, MLl2, MLl3, ML23 and ML0123-, disease severiety, percent ripened grains, and yield of ML01 and ML12, respectively did not show significant difference with those of mean values of their components. But degree of disease severity of the other mixtures, respectively -ML02, ML03, MLl3, ML23, and ML0123-was less than the mean of their components. Percent ripened grains and yield of them were higher than those of mean of their components. ML03, MLl3, ML23 and ML0123 comprised of the equal amount of two or four components having different resistant gene, these mixtures appeared to be a desirable combination for delaying spread of the pathogen, stabilizing of the race structure of the pathogen population, and extending durability of a cultivar with monogenic resistance.