• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.162-168
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• 2007

Compatible and incompatible interactions of near-isogenic lines containing one of Xa1, Xa3, and Xa7 resistance genes with Japanese bacterial blight isolates (T7174, T7147, and T7133) were examined in order to determine the variation of bacterial blight resistance and the stability of resistance gene. IRBB 101 line having a Xal gene was compatible (host susceptible) with T7147 and T7133 isolates but incompatible (host resistant) with T7174 isolate at all the tested rice growth stages. IRBB 103 line having a Xa3 gene was susceptible or moderately resistant to the three isolates at seedling and maximum tillering stage but resistant at heading stage. IRBB 101 line having a Xa7 gene was semi-compatible with the three isolates at seedling stage but incompatible at the other growth stages. Overall there were clear differences between compatible and incompatible interactions of rice with Xanthomonas oryzae pv. oryzae races. In the mixed inoculations of compatible and incompatible isolates, the lesion length from near-isogenic lines decreased as the ratios of incompatible races increased. When the distinction between compatible and incompatible isolates was unclear, there was almost no variation of lesion length regardless of mixed ratios. The pathogenicity of the mixed races in the incompatible Interactions increased rather than the individual inoculation whereas the lesion length of compatible interactions was similar to that of the individual inoculation. These data indicate the incompatible races inhibit the virulence of a compatible race but compatible races increase the disease occurrence due to incompatible races. Furthermore, IRBB 107 line that showed resistance to all the isolates at all the tested growth stages was considered as a good parent f3r breeding of resistant variety.

• Korean Journal of Breeding Science
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• v.42 no.4
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• pp.357-364
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• 2010

In a previous study, we mapped 12 QTLs for 1,000 grain weight (TGW) in the 172 $BC_2F_2$ lines derived from a cross between Oryza sativa ssp. Japonica cv. Hwaseongbyeo and O. rufipogon. These QTLs explained 5.4 - 11.4% of the phenotypic variance for TGW. Marker-aided selection combined with backcrosses was employed to develop QTL-NILs for each QTL. $BC_2F_2$ lines with each target QTL were backcrossed to Hwaseongbyeo twice and then allowed to self to produce $BC_4F_5$ populations. SSR markers linked to TGW were employed to select QTL-NILs with the respective target QTL. Six QTL-NILs with the recurrent parent, Hwaseongbyeo were evaluated for nine traits for three years from 2007 and 2009. Differences were observed between each of the 6 QTL-NILs and Hwaseongbyeo in TGW. In addition to TGW, these QTL-NILs displayed differences in other agronomic traits possibly indicating a tight linkage of genes controlling these traits. The direction of the QTL for TGW in 6 QTL-NILs was consistent as in the $BC_2F_2$ lines from the same cross. Difference in TGW between each of the QTL-NILs and Hwaseongbyeo was associated with the difference in one or two grain shape traits; grain length, grain width, and grain thickness. SSR markers linked to the QTL for TGW will facilitate selection of the grain shape character in a breeding program to diversify grain shape and provide the foundation for map-based gene isolation. Also, the QTL-NILs developed in this report and the progenies from crosses between the QTL-NILs will be useful in clarifying epistatic interactions among QTLs for TGW.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.304-310
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• 2011

In previous studies, we reported QTLs for grain weight (GW), qGW3 and for spikelets per panicle (SPP), qSPP3 linked to RM60 on chromosome 3 using advanced backcross lines derived from a cross between Oryza sativa ssp. Indica cv. Milyang 23 and O. glaberrima. The O. glaberrima alleles at this locus increased GW and spikelets per panicle in the Milyang 23 background. To further confirm and narrow down the position of the QTLs on chromosome 3, substitution mapping was performed using five lines containing the target O. glaberrima segment on chromosome 3. The size and position of the O. glaberrima segment on chromosome 3 were different in each line. These lines possessed 3-10 non-target O. glaberrima introgressions in the Milyang 23 background. These five lines were evaluated for seven agronomic traits including 1,000 grain weight and spikelets per panicle and also genotyped with seven SSR markers. Four lines were informative in delimiting the position of QTLs, qGW3 and qSPP3. Two lines with the O. glaberrima segment flanked by SSR markers, RM60 and RM523 displayed significantly higher values than Milyang 23 in GW and SPP whereas two lines without that O. glaberrima segment displayed no difference in GW and SPP compared to Milyang 23. The result indicates that two QTL, qGW3 and qSPP3 are located in the interval between RM60 and RM523 which are 1.2-Mb apart. Introgression lines having QTLs, qGW3 and qSPP3 would be useful materials not only to indentify the relationship between these two yield QTLs, but also to develop high yielding variety via marker-aided selection technology.

• 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.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.428-432
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• 2015

Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp.) collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum) pepper plants carrying $Bs_1$, $Bs_2$ and $Bs_3$, and PI235047 (C. pubescens) were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 and P8 were also observed. This is the first report of races P7 and P8 in Korea. The races P7 and P8 were differentiated from the former races P1 and P3, respectively, on the basis of their ability to elicit hypersensitive reactions to PI235047.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.412-419
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• 2009

In order to study the inheritance of watermelon seed size, we used six watermelon lines of different seed sizes as parental lines. Six lines include three accessions, 'PI525088' with giant seed (GS), 'Charleston Gray' with big seed (BS), and 'NT' with normal medium size seed (NS), and three near isogenic lines, 'NTss' with small seed (SS), 'NTms' with micro seed (MS) and 'NTts' with tomato seed size (TS) bred by crosses between accession 'NT' of normal seed size and accession 'TDR' of the smallest seed size,. We inspected $F_1$, $F_2$, $BC_1F_1$ (P1), $BC_1F_1$ (P2) populations from the crosses between the adjacent seed size materials like $GS{\times}BS$, $BS{\times}NS$, $NS{\times}SS$, and $MS{\times}TS$, and two crosses between parental lines showing relatively big difference in seed size such as $GS{\times}TS$ and $NS{\times}TS$. Partial single dominant inheritance patterns were observed between $GS{\times}BS$, $NS{\times}SS$, and $MS{\times}TS$ and inheritance patterns based on two genes or more than two genes were speculated between $BS{\times}NS$. A very wide segregation range was observed from the population of $GS{\times}TS$ indicating many quantitative genes involved in the seed sizes. Overall, we speculated that more than six genes are involved in between the biggest and smallest seed size watermelon and three major genes between the normal seed size and the smallest seed size watermelon.

• Korean Journal Plant Pathology
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• v.1 no.1
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• pp.79-84
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• 1985

Some characteristics of the resistance induced by Erysiphe graminis f. sp. hordei on near-isogenic barley leaves were evaluated. Inoculation of heat-killed incompatible inducer conidia did not protect barley leaves against compatible challenger race when the inducer inoculum was removed prior to inoculation of challenger. However, the colony formation of challenger race was greatly reduced by 87.1 to $91.2\%$ when the heat-killed inducer inoculum was not removed from the leaves. Although incompatible inducer conidia were removed before they penetrate the host cell, colony formation of challenger was markedly decreased without change in its infection type. After penetrating the host cell by inducer, however, a change in infection types occurred on the challenged leaves. Irrespective of compatibility of previously inoculated inducer on middle part of leaves, there was no reduction in colony formation of challenger race both on the adjacent acropetal and basipetal parts of the same leaves free of inducer inoculation. The colonies formed on the basipetal part by challenger race showed normal 4 type, whereas the infection type of colonies formed on the acropetal part was somewhat changed, thereby sporulation being reduced. The possibility of translocation of resistance-inducing factors was discussed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.32-32
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• 2017

To increase rice production, manipulating plant architecture, especially developing new high-yielding cultivars with erect leaves, is crucial in rice breeding programs. Leaf inclination angle determines the light extinction coefficient (k) of the canopy. Erect leaves increase light penetration into the canopy and enable dense plantings with a high leaf area index, thus increasing biomass production and grain yield. Because of erect leaves, the high-yielding indica rice cultivar 'Takanari' has smaller k during ripening than 'Koshihikari', a japonica cultivar with good eating quality. In our previous study, using chromosome segment substitution lines (CSSLs) derived from a cross between 'Takanari' and 'Koshihikari', we detected seven quantitative trait loci (QTLs) for leaf inclination angle on chromosomes 1 (two QTLs), 2, 3, 4, 7, and 12. In this study, we developed a near-isogenic line (NIL-3) carrying a 'Takanari' allele for increased leaf inclination angle on chromosome 3 in the 'Koshihikari' genetic background. We compared k, dry matter production, and grain yield of NIL-3 with those of 'Koshihikari' in the field from 2013 to 2016. NIL-3 had higher inclination angles of the flag, second, and third leaves at full heading and 3 (- 4) weeks after full heading and smaller k of the canopy at the ripening stage. Biomass at full heading and leaf area index at full heading and at harvest did not significantly differ between NIL-3 and 'Koshihikari'. However, biomass at harvest was significantly greater in NIL-3 than in 'Koshihikari' due to a higher net assimilation rate at the ripening stage. The photosynthetic rates of the flag and third leaves did not differ between NIL-3 and Koshihikari at ripening. Grain yield was higher in NIL-3 than 'Koshihikari'. Higher panicle number per square meter in NIL-3 contributed to the higher grain yield of NIL-3. We conclude that the QTL on chromosome 3 increases dry matter and grain production in rice by increasing leaf inclination angle.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.358-362
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• 2004

In order to develop molecular markers related to stay green phenotype, AFLP analysis was conducted using near-isogenic lines for either stay green or non stay green trait. Both lines have characteristics of multi-ear and tillers (MET). Two out of 64 primer combinations of selective amplification identified three reproducible polymorphic fragments in MET corn with stay green. Both of E+AGC/M+CAC and E+AAG/M+CAA primer combinations produced two and one specific polymorphic fragments linked to stay green trait, respectively. For the conversion of AFLPs to sequence tag sites (STSs), primers were designed form both end sequences of each two polymorphic fragments. One fragment, which was amplified with E+AAG/M+CAA primer combinations, possessed 298 bp long and showed a $91\%$ homology with maize retrotransposon Cinful-l. One out of two polymorphic fragments produced with E+AGC/M+CAC primer combination had 236 bp long and matched a $96\%$ homology with an intron region of 22kDa alpha zein gene cluster in Zea mays. One out of two PCR fragments amplified with MET2 primer set in the stay green MET was not produced in the non-stay green MET. The developed AFLP and STS marker could be used as an efficient tool for selection of the stay green trait in the MET inbred.

• Research in Plant Disease
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• v.16 no.3
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• pp.224-231
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• 2010

Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight (BLB) of rice, had been collected and identified using Biolog and fatty acid analysis. Epidemics of BLB had been occurred all the times at several rice cultivating areas in Korea in 1999-2004. Most X. oryzae pv. oryzae isolated in 1999 and 2002 belonged to Korean race K1, but more than 50% of the pathogen isolated in 2003 belonged to Korean race K3. Especially, most pathogens isolated in Jeonnam and Joenbuk provinces belonged to Korean race K3. Inoculation test of near isogenic lines (NIL) of rice carrying single resistance genes against BLB showed that many isolates belonging to Korean race 1 reacted differently to diverse resistant monogenic lines of rice. Southern blot analysis also showed that the bacterial pathogens belonged to the same race had different numbers of avirulence genes. This results suggested that each Korean race type may respond to many resistance genes of rice. All the K3 races isolated in Jeonnam and Joenbuk provinces were able to cause disease on Xa3 monogenic lines of rice. Since most rice cultivars cultivated in Jeonnam and Jeonbuk were carrying Xa3 resistance genes, the bacterial pathogens isolated in Jeonnam and Jeonbuk were likely to develop to adapt to Xa3 resistance gene. Together with avirulence gene patterns of the bacterial isolates and the results of disease reaction of monogenic lines of rice to them, Korean X. oryzae pv. oryzae was classified into 19 pathotypes. This newly classified pathotypes should help the breeding of new resistance rice cultivars in Korea.