• Plant Breeding and Biotechnology
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• 제7권3호
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• pp.272-286
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• 2019

Developing elite hybrid rice varieties is one important objective of rice breeding programs. Several genes related to male sterilities, restores, and pollinators have been identified through map-based gene cloning within natural variations of rice. These identified genes are good targets for introducing genetic traits in molecular breeding. This study was conducted to breed elite hybrid lines with major genes related to hybrid traits and disease/insect resistance in 240 genetic resources and F₁ hybrid combinations of rice. Molecular markers were reset for three major hybrid genes (S5, Rf3, Rf4) and thirteen disease/insect resistant genes (rice bacterial blight resistance genes Xa3, Xa4, xa5, Xa7, xa13, Xa21; blast resistance genes Pita, Pib, Pi5, Pii; brown planthopper resistant genes Bph18(t) and tungro virus resistance gene tsv1). Genotypes were then analyzed using molecular marker-assisted selection (MAS). Biological assay was then performed at the Red River Delta region in Vietnam using eleven F₁ hybrid combinations and two control vatieties. Results showed that nine F₁ hybrid combinations were highly resistant to rice bacterial blight and blast. Finally, eight F₁ hybrid rice varieties with resistance to disease/insect were selected from eleven F₁ hybrid combinations. Their characteristics such as agricultural traits and yields were then investigated. These F₁ hybrid rice varieties developed with major genes related to hybrid traits and disease/insect resistant genes could be useful for hybrid breeding programs to achieve high yield with biotic and abiotic resistance.

• 원예과학기술지
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• 제33권5호
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• pp.722-729
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• 2015

딸기 흰가루병은 Podosphaera aphanis에 의해 발병되며 수확기에 가장 큰 피해를 주는 병으로 현재 유황, 농약으로 주로 방제 되고 있는 실정이다. 본 연구에서는 딸기 흰가루병 저항성 품종 육성을 위한 흰가루병 저항성 특이마커 개발로 내병성 육종효율을 높이고자 하였다. 흰가루병 저항성 계통 선발을 위한 분자마커를 개발하기 위해 아키히메${\times}$설향 집단을 대상으로 자가수분을 통해 후대 양성 후 병저항성을 검정하였다. 마커분석은 RAPD primer 200 세트 중 OPE10 331bp에서부터 흰가루병 저항성 특이 마커 선발하였다. 흰가루병 저항성 특이밴드만 선발하기 위하여 클로닝 후 유전자정보 분석하여 SP1F/R의 Primer를 제작하였다. 그러나 SP1F/R을 이용하여 PCR한 결과 저항성, 감수성간에 다형성이 확인되지 않아 염기서열을 정렬한 후 SNP, In/del의 다형성 유무를 확인한 결과 6개의 SNP를 확인하였다. 이들 PCR 산물을 해당 사이트와 연관된 제한효소로 절단한 결과 그 중 Eae I(Y/GGCCR)의 절단으로 231bp 위치에서 저항성과 감수성간의 다형성을 확인함으로써 흰가루병 저항성 계통선발을 위한 분자마커를 선발하였다. 이러한 과정을 통해 딸기 흰가루병 저항성 품종 육성을 위한 MAS(marker assisted selection) 체계 확립으로 내병성 육종효율 증진에 기여를 할 수 있을 것으로 기대된다.

• Molecules and Cells
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• 제26권2호
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• pp.146-151
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• 2008

The brown planthopper (BPH) is a major insect pest in rice, and damages these plants by sucking phloem-sap and transmitting viral diseases. Many BPH resistance genes have been identified in indica varieties and wild rice accessions, but none has yet been cloned. In the present study we report fine mapping of the region containing the Bph1 locus, which enabled us to perform marker-aided selection (MAS). We used 273 F8 recombinant inbred lines (RILs) derived from a cross between Cheongcheongbyeo, an indica type variety harboring Bph1 from Mudgo, and Hwayeongbyeo, a BPH susceptible japonica variety. By random amplification of polymorphic DNA (RAPD) analysis using 656 random 10-mer primers, three RAPD markers (OPH09, OPA10 and OPA15) linked to Bph1 were identified and converted to SCAR (sequence characterized amplified region) markers. These markers were found to be contained in two BAC clones derived from chromosome 12: OPH09 on OSJNBa0011B18, and both OPA10 and OPA15 on OSJNBa0040E10. By sequence analysis of ten additional BAC clones evenly distributed between OSJNBa0011B18 and OSJNBa0040E10, we developed 15 STS markers. Of these, pBPH4 and pBPH14 flanked Bph1 at distances of 0.2 cM and 0.8 cM, respectively. The STS markers pBPH9, pBPH19, pBPH20, and pBPH21 co-segregated with Bph1. These markers were shown to be very useful for marker-assisted selection (MAS) in breeding populations of 32 F6 RILs from a cross between Andabyeo and IR71190, and 32 F5 RILs from a cross between Andabyeo and Suwon452.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.772-779
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• 2005

The objectives of this study were to examine problems with using F$_1$ data by simulation, association of marker loci and QTL from crosses of inbred parental lines and to enumerate the preliminary characterization of genetic superiority within inbred parental lines. In this study, the association between markers for QTL used as covariates and estimates of variance components due to effects of lines was investigated through computer simulation. The effects of size of population to develop inbred lines and initial frequencies and magnitudes of effects of QTL were also considered. Results show that estimates of variance components due to line effects are influenced by including marker information as covariates in the model for analysis. Estimates of line variance were increased by adding marker information into the analysis, because negative covariances between effects associated with the markers and the remaining effects associated with other loci existed. However, the fit of the model as indicated by the log likelihood improved by adding more markers as covariates into the analysis. Marker assisted selection will be beneficial when markers explain unexplained genetic difference during selection procedure. Markers can be used to identify QTLs affecting traits, and to select for favorable QTL alleles. To efficiently use genetic markers, location of markers at the genome must be identified. The estimates of variance due to effects of with and without marker information used as covariates in the analysis were investigated. The estimates of line variances were always increased when markers were included as covariates for the model because a negative covariance were existed.

• International Journal of Industrial Entomology and Biomaterials
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• 제10권2호
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• pp.79-86
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• 2005

Molecular markers have increasingly been used in plant genetic analysis, due to their obvious advantages over conventional phenotypic markers, as they are highly polymorphic, more in number, stable across different developmental stages, neutral to selection and least influenced by environmental factors. Among the PCR based marker techniques, ISSR is one of the simplest and widely used techniques, which involves amplification of DNA segment present at an amplifiable distance in between two identical microsatellite repeat regions oriented in opposite direction. Though ISSR markers are dominant like RAPD, they are more stable and reproducible. Because of these properties ISSR markers have recently been found using extensively for finger printing, pohylogenetic analysis, population structure analysis, varietal/line identification, genetic mapping, marker-assisted selection, etc. In mulberry (Morus spp.), ISSR markers were used for analyzing phylogenetic relationship among cultivated varieties, between tropical and temperate mulberry, for solving the vexed problem of identifying taxonomic positions of genotypes, for identifying markers associated with leaf yield attributing characters. As ISSR markers are one of the cheapest and easiest marker systems with high efficiency in generating polymorphism among closely related varieties, they would play a major role in mulberry genome analysis in the future.

• Horticulture, Environment, and Biotechnology : HEB
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• 제59권6호
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• pp.857-864
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• 2018

Previous studies have not detected transcripts of the gene encoding anthocyanidin synthase (ANS) in white pomegranates (Punica granatum L.) and suggest that a large-sized insertion in the coding region of the ANS gene might be the causal mutation. To elucidate the identity of the putative insertion, 3887-bp 5' and 3392-bp 3' partial sequences of the insertion site were obtained by genome walking and a gene coding for an expansin-like protein was identified in these genome-walked sequences. An identical protein (GenBank accession OWM71963) isolated from pomegranate was identified from BLAST search. Based on information of OWM71963, a 5.8-Mb scaffold sequence with genes coding for the expansin-like protein and ANS were identified. The scaffold sequence assembled from a red pomegranate cultivar also contained all genome-walked sequences. Analysis of positions and orientations of these genes and genome-walked sequences revealed that the 27,786-bp region, including the 88-bp 5' partial sequences of the ANS gene, might be translocated into an approximately 22-kb upstream region in an inverted orientation. Borders of the translocated region were confirmed by PCR amplification and sequencing. Based on the translocation mutation, a simple PCR codominant marker was developed for efficient genotyping of the ANS gene. This molecular marker could serve as a useful tool for selecting desirable plants at young seedling stages in pomegranate breeding programs.

• Journal of Crop Science and Biotechnology
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• 제11권4호
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• pp.263-268
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• 2008

Bacterial leaf pustule (BLP) caused by Xanthomonas axonopodis pv. glycines is a serious disease to make pustule and chlorotic haloes in soybean [Glycine max (L). Merr.]. While inheritance mode and map positions of the BLP resistance gene, rxp are known, no sequence information of the gene was reported. In this study, we made five near isogenic lines (NILs) from separate backcrosses (BCs) of BLP-susceptible Hwangkeumkong $\times$ BLP-resistant SS2-2 (HS) and BLP-susceptible Taekwangkong$\times$ SS2-2 (TS) through foreground and background selection based on the four-stage selection strategy. First, 15 BC individuals were selected through foreground selection using the simple sequence repeat (SSR) markers Satt486 and Satt372 flanking the rxp gene. Among them, 11 BC plants showed the BLP-resistant response. The HS and TS lines chosen in foreground selection were again screened by background selection using 118 and 90 SSR markers across all chromosomes, respectively. Eventually, five individuals showing greater than 90% recurrent parent genome content were selected in both HS and TS lines. These NILs will be a unique biological material to characterize the rxp gene.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.34-34
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• 2003

한국산 선발계통 및 일본산 양식계통과 이들 두 계통간 잡종 참돔 집단의 유전적 특성을 분석하기 위하여, RAPD (Random Amplified Polymorphic DNA) marker를 탐색하였다. 10개의 염기로 이루어진 200개의 random primer 분석을 통하여 polymorphic pattern을 나타내는 23개의 random primer를 선발하였으며, 각 primer의 재현성을 확인하였다. 이들 중 OPA-11 primer는 크기가 각각 600 bp, 650 bp 및 750 bp 인 3개의 DNA 단편에 의하여 4개의 genotype을 나타냈으며, 각 genotype의 빈도는 집단간차이를 보였고, 한국산 선발계통 집단에서는 4개의 genotype이 모두 발견되는 반면, 일본산 양식계통 및 일본산 양식계통을 포함한 교배집단에서는 특정 genotype만 발견되었다. OPA-11 primer 유래의 polymorphic DNA 단편을 cloning하고 염기서열을 결정하였으며, SCAR (Sequence Characterized Amplified Region) primer를 제작하고 분석하였다. 본 연구는 참돔집단의 유전적 특성 파악 및 집단 구별에 RAPD marker를 활용하였으며, 참돔 육종시 형질 및 기능관련 DNA marker 탐색에 적용하기 위하여, 이후의 연구에서는 SCAR과 RFLP 분석에 RAPD marker를 이용하여 100% 정확도를 갖는 RFLP maker를 찾고, MAS (Marker-Assisted Selection)에 적용하고자 한다.

• 한국육종학회지
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• 제43권5호
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• pp.360-367
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• 2011

Beta-carotene producing transformants were produced in the background of 'Nagdongbyeo', a Japonica rice cultivar. Introgression of the carotenoid locus in the transformant, PAC4-2 into the elite cultivar 'Ilpumbyeo' was started. To initiate a backcrossing program, we surveyed 220 SSR markers and found that 38% of them were polymorphic between 'Ilpumbyeo' as a recurrent parent and the PAC4-2 as a recipient parent. The selection strategy comprising foreground and background selection was employed. First, foreground selection was practiced in $BC_1$, $BC_2$, and $BC_3$ generations using the transgene specific PCR-based marker in addition to visual scoring of the seed color. Marker-based background selection combined with phenotypic selection was employed from $BC_3F_2$ to $BC_3F_4$ generations. Blast search indicated that the transgene PAC4-2 was located between SSR markers, RM6 and RM482. 240 $BC_3F_3$ and 63 $BC_3F_4$ lines were evaluated for four agronomic traits including days to heading. Most of the lines were similar to Ilpumbyeo in agronomic traits evaluated. The percentage of PAC4-2 genome ranged from 4% to 21% with a mean of 12.5%, which was higher than the expected for an unselected $BC_3$ backcross population. This could be explained by the fact that two genes for beta-carotene and the stripe virus resistance were targeted in this study. We selected 10 representative $BC_3F_5$ lines from 63 $BC_3F_4$ lines based on agronomic traits and carotenoids content. The selection strategy would be appropriate for the introgression of beta-carotene gene in a breeding program.

• 한국육종학회지
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• 제43권4호
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• pp.273-281
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• 2011

Fusarium head blight (FHB), also known as scab, caused mainly by Fusarium graminearum is a devastating disease of wheat in regions that are warm and humid during flowering. In addition to significant yield and quality losses, the mycotoxin deoxynivalenol produced by the pathogen in infected wheat kernels is a serious problem for food and feed safety. Twenty- three Korean cultivars and "Sumai 3", which is a FHB-resistant Chinese cultivar were tested for Type I, Type II resistances of FHB. Three cultivars were identified as resistant in Type I assessment, and two cultivars were resistant in Type II assessment. Genetic variation and relationship among the cultivars were evaluated on the basis of 11 Simple Sequence Repeat (SSR) and 29 Sequence Tagged Site (STS) markers that were linked to FHB resistance Quantitative Trait Loci (QTL) on chromosome 3BS. One SSR and 7 STS markers detected polymorphisms. Especially, using a STS marker (XSTS3B-57), 32.4% of the variation for Type II FHB resistance could be explained. Genetic relationship among Korean wheat cultivars was generally consistent with their released year. These markers on chromosome 3BS have the potential for accelerating the development of Korean wheat cultivars with improved Fusarium head blight resistance through the use of marker-assisted selection.