• Title/Summary/Keyword: Backcross Population

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Detection of QTLs Influencing Panicle Length, Panicle Grain Number and Panicle Grain Sterility in Rice(Oryza sativa L.)

  • Ahamadi, Jafar;Fotokian, M.H.;Fabriki-Orang, S.
    • Journal of Crop Science and Biotechnology
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    • v.11 no.3
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    • pp.163-170
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    • 2008
  • The detection, characterization and use of quantitative traits loci, QTL, have significant potential to improve the efficiency of selective breeding of species. Therefore, a population with 59 advanced backcross lines($BC_2F_5$), derived from a cross between IR64 and Tarome molaei, were studied in Tonekabon Rice Research Station of Iran in order to map QTLs for panicle length, number of grain per panicle, and panicle grain sterility in rice. The parental screening wtih 235 SSR markers in agarose and polyacrylamide gels revealed 114 markers with clear polymorphic bands. To search for QTLs associated with panicle length, number of grain per panicle, and panicle grain sterility, we constructed a genetic linkage map using 114 microsatellite markers. Positive and negative transgressive segregations were observed in $BC_2F_5$ lines for all traits. Using multiple interval mapping(MIM), a total of 20 putative QTLs were detected, of which eight were for panicle length, three for number of grains, and nine for panicle grain sterility. The maximum number of QTLs were mapped on chromosomes 1 and 2 with eight QTLs. These QTL markers could possible be utilized for marker-assisted selection.

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Identification of New Source of Resistance to Powdery Mildew of Indian Mustard and Studying Its Inheritance

  • Nanjundan, Joghee;Manjunatha, Channappa;Radhamani, Jalli;Thakur, Ajay Kumar;Yadav, Rashmi;Kumar, Arun;Meena, Mohan Lal;Tyagi, Rishi Kumar;Yadava, Devender Kumar;Singh, Dhiraj
    • The Plant Pathology Journal
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    • v.36 no.2
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    • pp.111-120
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    • 2020
  • Powdery mildew of Indian mustard (Brassica juncea), caused by Erysiphe cruciferarum, is emerging as major problem in India. All the Indian mustard cultivars presently grown in India are highly susceptible to powdery mildew and so far no resistance source has been reported. In this study, with an aim to identify resistant source, 1,020 Indian mustard accessions were evaluated against E. cruciferarum PMN isolate, at Wellington, The Nilgiris, Tamil Nadu, India under natural hot spot conditions. The study identified one accession (RDV 29) with complete resistance against E. cruciferarum PMN isolate for the first time, which was consistent in five independent evaluations. Genetic analysis of F1, F2 and backcross populations obtained from the cross RSEJ 775 (highly susceptible) × RDV 29 (highly resistant) for two season revealed that the resistance is governed by two genes with semi-dominant and gene dosage effect. Further, a new disease rating system using six scales (0, 1, 2, 3, 4, and 5) has also been proposed in this study to score powdery mildew based on progress of fungal growth in different plant parts of the F2 population. The outcome of this study viz. newly identified powdery mildew-resistant Indian mustard accession (RDV 29), information on inheritance of resistance and the newly developed disease rating scale will provide the base for development of powdery mildew-resistant cultivars of Indian mustard.

Marker Assisted Development and Characterization of Beta-Carotene Rice

  • Yang, Paul;Song, Mi-Hee;Ha, Sun-Hwa;Kim, Jae-Kwang;Park, Jong-Seok;Ahn, Sang-Nag
    • Korean Journal of Breeding Science
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    • v.43 no.5
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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.

The Construction of a Chinese Cabbage Marker-assisted Backcrossing System Using High-throughput Genotyping Technology

  • Kim, Jinhee;Kim, Do-Sun;Lee, Eun Su;Ahn, Yul-Kyun;Chae, Won Byoung;Lee, Soo-Seong
    • Horticultural Science & Technology
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    • v.35 no.2
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    • pp.232-242
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    • 2017
  • The goal of marker-assisted backcrossing (MAB) is to significantly reduce the number of breeding generations required by using genome-based molecular markers to select for a particular trait; however, MAB systems have only been developed for a few vegetable crops to date. Among the types of molecular markers, SNPs (single-nucleotide polymorphisms) are primarily used in the analysis of genetic diversity due to their abundance throughout most genomes. To develop a MAB system in Chinese cabbage, a high-throughput (HT) marker system was used, based on a previously developed set of 468 SNP probes (BraMAB1, Brassica Marker Assisted Backcrossing SNP 1). We selected a broad-spectrum TuMV (Turnip mosaic virus) resistance (trs) Chinese cabbage line (SB22) as a donor plant, constructing a $BC_1F_1$ population by crossing it with the TuMV-susceptible 12mo-682-1 elite line. Foreground selection was performed using the previously developed trsSCAR marker. Background selection was performed using 119 SNP markers that showed clear polymorphism between donor and recipient plants. The background genome recovery rate (% recurrent parent genome recovery; RPG) was good, with three of 75 $BC_1F_1$ plants showing a high RPG rate of over 80%. The background genotyping result and the phenotypic similarity between the recurrent parent and $BC_1F_1$ showed a correlation. The plant with the highest RPG recovery rate was backcrossed to construct the $BC_2F_1$ population. Foreground selection and background selection were performed using 169 $BC_2F_1$ plants. This study shows that, using MAB, we can recover over 90% of the background genome in only two generations, highlighting the MAB system using HT markers as a highly efficient Brassica rapa backcross breeding system. This is the first report of the application of a SNP marker set to the background selection of Chinese cabbage using HT SNP genotyping technology.

Evaluation of Early Generation of Crosses for Incorporation of Resistance to Bacterial Spot into Sweet Pepper (감미종(甘味種) 고추에 더뎅이병(病) 저항성(抵抗性)을 도입(導入)하기 위한 교잡(交雜) 초기세대(初期世代) 검정(檢定))

  • Jeong, Ho Jeong;Kim, Byung Soo;Shon, Eun Young
    • Current Research on Agriculture and Life Sciences
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    • v.12
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    • pp.23-28
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    • 1994
  • A leading sweet pepper cultivar, Keystone Resistant Giant #3, was crossed with a line with resistance to Xanthomonas campestris pv. vesicatoria, PI271322, for incorporation of the resistance and to study the inheritance of resistance to the disease. Seedlings of parents, $F_1$, $F_2$ and backcross populations of a cross between Keystone Resistant Giant #3 and PI271322 were inoculated with race 1 and race 3 of Xanthamonas campestris pv. vesicatoria by infiltrating bacterial suspension into abaxial side of leaves. PI271322 was carrying a gene ($Bs_3$) for hypersensitive resistance to race 1 of X. c. pv. vesicatoria and also a component of non-hypersensitive resistance to race 3 inheriting in a quantitative mode. Correlation coefficient between disease indices to race 1 and race 3 of non-hypersensitive plants in $F_2$ population was highly significant, thus indicating that a component of non-hypersensitive general resistance in PI271322 acted consistently to both races. Individual plants with resistance to both race 1 and race 3 of X. c. pv. vesicatoria were selected and a breeding program for incorporation of the resistance is continued.

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QTLs Identification and Confiirmation of Field Resistance to Leaf Blast in Temperate japonica Rice (Oryza sativa L.)

  • Cho, Young-Chan;Kwon, Soon-Wook;Suh, Jung-Pil;Kim, Jeong-Ju;Lee, Jeom-Ho;Roh, Jae-Hwan;Oh, Myung-Kyu;Kim, Myeong-Ki;Ahn, Sang-Nag;Koh, Hee-Jong;Yang, Sae-Jun;Kim, Yeon-Gyu
    • Journal of Crop Science and Biotechnology
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    • v.11 no.4
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    • pp.269-276
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    • 2008
  • Field resistance is defined as the resistance that allows effective control of a parasite under natural field condition and is durable when exposed to new races of that parasite. To identify the genes for field resistance to rice blast, quantitative trait loci (QTLs) conferring the resistance for races and blast nursery screening in japonica rice cultivars were detected and mapped using SSR markers. QTL analysis was carried out in 190 RILs population from the cross between Suweon365 (moderately resistant) and Chucheong (highly susceptible). Twelve QTLs against nine blast races inoculated were detected on chromosomes 1, 2, 4, 6, 7, 11 and 12. They explained from 5.1% to 34.9% of total phenotypic variation. Eight QTLs against blast nursery screening in four regions for three years were detected on chromosomes 1, 2, 4, 11 and 12. The phenotypic variation explained by each QTL ranged from 4.3% to 37.7%. Three chromosome segment substitution lines (CSSLs) of $BC_2F_6$ by backcross method were developed to transfer the QTLs into the susceptible cultivar Chucheong as a recurrent parent. A CSSL4-1 containing two QTLs qLB6.2 and qLB7 against blast races showed to the reaction of 6 to 7 at blast nursery in two regions for two years. The CSSL4-2 and CSSL93 containing QTLs, qLB11.2 and qLB12.1 of the resistance against leaf blast in blast nursery screening, respectively, had enhanced the resistance for blast nursery screening across two regions and in two years.

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Identification of a Major QTL, qSTV11SG, Associated with Resistance to Rice Stripe Virus Disease Originated from Shingwangbyeo in Rice (Oryza Sativa L.) (신광벼 유래의 벼 줄무늬잎마름병 저항성 주동 QTL qSTV11SG탐색)

  • Kwak, Do-Yeon;Lee, Bong-Chun;Choi, Ilyoung;Yeo, Un-Sang;Cho, Jun-Hyun;Lee, Ji-Yoon;Song, You-Chun;Yun, Yeong-Nam;Park, Dong-Soo;Kang, Hang-Won;Nam, Min-Hee;Lee, Jong-Hee
    • Korean Journal of Breeding Science
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    • v.43 no.5
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    • pp.464-469
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    • 2011
  • Virus diseases often cause serious damage to rice production in Asia. The lack of information on virus resistance genes has been a major obstacle for the breeding of resistant varieties. In order to identify DNA marker associated with resistance against rice stripe virus (RSV), the quantitative trait locus (QTL) was carried out using advanced backcross population developed from a cross between RSV-resistant tongil type cultivar Shinkwang and susceptible japonica cultivar Ilpum. A RSV resistance QTL $qSTV11^{SG}$ explaining 44.2% of the phenotypic variation was identified on chromosome 11 of Tongil type rice cultivar 'Shingwang'. $qSTV11^{SG}$ was tightly linked to DNA marker RM6897. The RM6897 divided as resistance type allele and susceptible type alleles. Twenty seven resistant varieties showed the resistant-type allele and 23 susceptible varieties were susceptible-type allele to the marker of RM6897. This results and the molecular markers presented here may be useful in rice breeding for improving RSV resistance in japonica rice.

Analysis of phenotypic characterization of segregation population developed by crossing in Flammulina velutipes (팽이버섯(Flammulina velutipes) 교잡분리집단의 형태학적 특성 분석)

  • Woo, Sung-I;Kong, Won-Sik;Kim, Eun-Seou;Jang, Kab yeul;Shin, Pyung-Gyun;Oh, Youn-Lee;Oh, Min ji;Nam, Youn-keol;Kim, Kyung-Soo
    • Journal of Mushroom
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    • v.13 no.3
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    • pp.217-222
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    • 2015
  • This study was conducted to obtain a growth correlation of basal information from the development of disease resistant Flammulina velutipes cultivars through back-crossing between the strains of wild-type brown monokaryon 4019-20 and the derivative of commercial quality white monokaryons 3. The two strains were selected to back-cross for further enhancing their latent attributes and growth characteristics. The parents of 4019-$20{\times}M3$ back-crossed to reproduce $F_1$, M3-Sn. Using $F_1$, M3-Sn procured and isolated into 94 monokaryon strains. Further examination of growth characteristics carried out by back-crossing between M3 and $BC_1F_1$ from M3-n dikaryon. Monokaryon exhibited an irregular growth pattern and demonstrated to be sluggish development in the sawdust medium. However $BC_1F_1$(M3-n) dikaryon strains confirmed mostly regular growth pattern and demonstrated ordinary growth in the sawdust medium. The fruitbody of $BC_1F_1$ confirmed as light-brown colour to be the dominant gene. The colour distributions of fruitbody, $BC_1F_1$, resulted as follows; 7% of dark brown, 25% of brown, 27% of light brown, 16% of ivory and 25% of white. The ratio of the other color to white showed 3 to 1 which suggested two major genes were related to fruitbody color.

Studies on the Breeding of the Response to short photoperiod, Fiber weight, and Qualitative characters and of the Associations Among these characters in Kenaf (섬유용양마의 육종에 관한 연구 -단일반응성과 섬유종의 유전 및 연소)

  • Johng-Moon Park
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.4 no.1
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    • pp.115-124
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    • 1968
  • It was shown that the most desirable characters for kenaf are high-fiber weight and moderately early maturity. Therefore, the objectives of this research on this crop is to find varieties possessing these characteristics. The experiments covered in this report provided new information relative to segregation, mode of inheritance, estimate of the number of genes involved in fiber weight and their response to short day length of 10 hours and the qualitative characters, such as, color of stem, capsule, petiole and shape of leaves. The associations which exist among these characters are also indicated. Fiber weight per plant, days to flowering, Stem color, Petiole color, Capsule color, and shape of leaves were studied in parental, $F_1$.$F_2$and backcross populations of a cross between Dashkent, a low-fiber weight but early maturing kenaf variety, and G 38 F-1, a high-fiber weight but late maturing kenaf variety. Crosses were made using the varieties, Dashkent and G 38 F-1 as parents. The Dashkent parent had the following characteristics: green stems, capsules and petioles and lobed shaped leaves; 105.8234 mean-days to flowering in the field, and 106.9222 mean-days under 10 hours short day treatment. The other parent, G 38 F-1 had red stems yellow capsules and red petioles and unlobed shaped leaves; 149.8921 mean-days to flowering in the field, and 62.3684 mean-days under 10 hours short day treatment. Both of the parents, $F_1$, $F_2$, $BC_1$ ($F_1$ X Dashkent, ) and $BC_2$($F_1$ ${\times}$ G38F-1) of the kenaf cross were grown at the Crops Experiment Station, Suwon, Korea in 1965. Color of stems, petioles and capsules, and shape of leaves were noted to be simply inherited as a single factor. Red stem color was dominant over green stem color, red petiole color was dominant over green petiole, lobed shaped leaves were dominant over unlobed shaped leaves and yellow capsules were dominant over green capsule. It was, also, noted that the factor for color of petiole was linked with the factor for shape of leaf with a 11.9587 percent recombination value, however no interaction or linkage were found among the color of stem and capsule color. Using Powers partitioning method, theoretical means and frequency distributions for each population, the days to flowering were calculated with the assumption that two gene pairs were involved. The values obtained fitted the theoretical values. In general this would indicate that Dashkent and G 38 F -1 were differentiated by two gene pairs. Heritability values were calculated as the percent of additive genetic variance. Heritability value of days to flowering, 89.5% in the broad sense and 79.91% in the narrow sense, indicated that the selection for this character would be effective in relatively early generations. Particularly, high positive correlations were found between days to flowering and the color of petioles and shape of leaves. However, there was no relation between days to flowering and capsule color nor between these and stem color. On the basis of the results of this experiment there is evidence that the hereditary factor for shape of leaves and the color of petioles is linked with an effective factor or factors for the characters of days to flowering. The association was sufficiently close to offer a possible simple and efficient means of selection for moderately early mat. uring plants by leaf shape and petiole color selection. Again using Powers partitioning method the frequency distribution for each population to the fiber weight were calculated with the assumption that two gene pairs, AaBb, were involved. Both phenotypic and genotypic dominance were complete. The obtained value did not agree with the theoretical value for $F_2$ and $BC_1$ ($F_1$ ${\times}$ Dashkent.) It seems that Dashkent and G 38 F-1 were differentiated by two major gene pairs but some the other minor genes are necessary. It is certain that the hereditary factor for shape of leaves and color of petioles is linked with an effective factor or factors for fiber weight. Also, high. yielding plants with moderately early maturity were found in the $F_2$ population. Thus, simultaneous selection for high-fiber yield and moderately early maturing plants should be possible in these populations. Phenotypic and genotypic correlation coefficients between fiber weight per plant and days to flowering, stem height and stem diameter were calculated. In general, genotypic correlations are higher than the phenotypic correlation. The highest correlation is found between stem height and fiber weight per plant (0.7852 in genotypic and 0.4103 in phenotypic) and between days to flowering and fiber weight per plant (0.7398 in genotypic and 0.3983 in phenotypic.) It was also expected that the selection of high stem height and moderately early maturing plants were given the efficient means of selection for high fiber weight.

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