Breeding Science
Online ISSN : 1347-3735
Print ISSN : 1344-7610
ISSN-L : 1344-7610
71 巻, 4 号
選択された号の論文の11件中1~11を表示しています
Cover
  • 2021 年 71 巻 4 号 p. cover
    発行日: 2021年
    公開日: 2021/10/01
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    On the cover

    Barley plants inoculated with GFP-expressing Barley yellow mosaic virus (BaYMV) to visualize virus replication and dynamics for understanding resistance mechanisms. GFP fluorescence of the susceptible cultivar ‘New Golden’ at 6 weeks post-inoculation of BaYMV pathotype V. Images are of leaves (upper) and roots (bottom) under white light (left) and UV light using a long-pass filter (right). Under UV light, GFP fluorescence was detected in the upper leaves and lateral roots (This issue, p. 484–490).

    (H. Nishigawa: School of Agriculture, Utsunomiya University)

Invited Review
  • Hiroshi Hisano, Fumitaka Abe, Robert E. Hoffie, Jochen Kumlehn
    原稿種別: Invited Review
    2021 年 71 巻 4 号 p. 405-416
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/27
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    The recent advent of customizable endonucleases has led to remarkable advances in genetic engineering, as these molecular scissors allow for the targeted introduction of mutations or even precisely predefined genetic modifications into virtually any genomic target site of choice. Thanks to its unprecedented precision, efficiency, and functional versatility, this technology, commonly referred to as genome editing, has become an effective force not only in basic research devoted to the elucidation of gene function, but also for knowledge-based improvement of crop traits. Among the different platforms currently available for site-directed genome modifications, RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) endonucleases have proven to be the most powerful. This review provides an application-oriented overview of the development of customizable endonucleases, current approaches to cereal crop breeding, and future opportunities in this field.

Research Papers
  • Chen Wang, Ning Hao, Yutong Xia, Yalin Du, Ke Huang, Tao Wu
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 417-425
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/18
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    電子付録

    Seed germination plays an important role in the initial stage of plant growth. However, few related studies focused on lethality after seed germination in plants. In this study, we identified an Ethyl methanesulfonate (EMS) mutagenesis mutant Csleth with abnormal seed germination in cucumber (Cucumis sativus L.). The radicle of the Csleth mutant grew slowly and detached from the cotyledon until 14 d after sowing. Genetic analysis showed that the mutant phenotype of Csleth was controlled by a single recessive gene. MutMap+ and Kompetitive Allele Specific PCR (KASP) genotyping results demonstrated that Csa3G104930 encoding 3-deoxy-manno-octulosonate cytidylyltransferase (CsKDO) was the candidate gene of the Csleth mutant. The transition mutation of aspartate occurred in Csa3G104930 co-segregated with the phenotyping data. CsKDO was highly expressed in male flowers in wild type cucumbers. Subcellular localization results showed that CsKDO was located in the nucleus. Overall, these results suggest CsKDO regulates lethality during seed germination in cucumber.

  • Kousuke Seki
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 426-434
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/20
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    Coupled with the reduction in sequencing costs, the number of RAD-seq analysis have been surging, generating vast genetic knowledge in relation with many crops. Specialized platforms might be intimidating to non-expert users and difficult to implement on each computer despite the growing interest in the usage of the dataset obtained by high-throughput sequencing. Therefore, RAD-R scripts were developed on Windows10 for RAD-seq analysis, allowing users who are not familiar with bioinformatics to easily analyze big sequence data. These RAD-R scripts that run a flow from raw sequence reads of F2 population for the self-fertilization plants to the linkage map construction as well as the QTL analysis can be also useful to many users with limited experience due to the simplicity of copying Excel cells into the R console. During the comparison of linkage maps constructed by RAD-R scripts and Stacks, RAD-R scripts were shown to construct the linkage map with less missing genotype data and a shorter total genetic distance. QTL analysis results can be easily obtained by selecting the reliable genotype data that is visually inferred to be appropriate for error correction from the genotype data files created by RAD-R scripts.

  • Michael O. Itam, Yasir S. A. Gorafi, Izzat S. A. Tahir, Hisashi Tsujim ...
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 435-443
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/18
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    Twenty-four wheat lines, developed by Aegilops tauschii Coss. introgressions and previously selected for heat or salinity stress tolerance, were evaluated under a drought-rewatering-drought cycle for two years. The objective was to select breeding lines that are resilient to more than one abiotic stress. The experiment was designed in alpha lattice with three replications. Drought was imposed by withholding water during flowering. The results revealed considerable genetic variability in physio-agronomic traits, reflecting the variation in the introgressed segments. High heritability estimates (above 47%) were recorded for most traits, including days to 50% heading, plant height, and thousand-grain weight, indicating the genetic control of these traits which may be useful for cultivar development. The trait-trait correlations within and between water regimes highlighted a strong association among the genetic factors controlling these traits. Some lines exhibited superior performance in terms of stress tolerance index and mean productivity compared with their backcross parent and elite cultivars commonly grown in hot and dry areas. Graphical genotyping revealed unique introgressed segments on chromosomes 4B, 6B, 2D, and 3D in some drought-resilient lines which may be linked to drought resilience. Therefore, we recommend these lines for further breeding to develop climate-resilient wheat varieties.

  • Motoyuki Ishimori, Hideki Takanashi, Masaru Fujimoto, Hiromi Kajiya-Ka ...
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 444-455
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/27
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    According to Fisher’s principles, an experimental field is typically divided into multiple blocks for local control. Although homogeneity is supposed within a block, this assumption may not be practical for large blocks, such as those including hundreds of plots. In line evaluation trials, which are essential in plant breeding, field heterogeneity must be carefully treated, because it can cause bias in the estimation of genetic potential. To more accurately estimate genotypic values in a large field trial, we developed spatial kernel models incorporating genome-wide markers, which consider continuous heterogeneity within a block and over the field. In the simulation study, the spatial kernel models were robust under various conditions. Although heritability, spatial autocorrelation range, replication number, and missing plots directly affected the estimation accuracy of genotypic values, the spatial kernel models always showed superior performance over the classical block model. We also employed these spatial kernel models for quantitative trait locus mapping. Finally, using field experimental data of bioenergy sorghum lines, we validated the performance of the spatial kernel models. The results suggested that a spatial kernel model is effective for evaluating the genetic potential of lines in a heterogeneous field.

  • Takuya Wada, Hiyori Monden, Sachiko Isobe, Kenta Shirasawa, Takayuki S ...
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 456-466
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/20
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    Male sterility is one of the reproductive isolation systems in plants and quite useful for F1 seed production. We previously identified three independent quantitative trait loci (QTLs) for male sterility of cultivated strawberry, Here, we identified the specific subgenomes in which these QTLs are located by QTL-seq approach. QTLs qMS4.1, qMS4.2, and qMS4.3 were mapped separately in subgenomes Fvb4-4, Fvb4-3, and Fvb4-1, respectively, in ‘Camarosa’ genome assembly v. 1.0.a1. Candidate regions of qMS4.1 and qMS4.3 were clearly detected around 12–26 Mb in Fvb4-4 and 12–14 Mb in Fvb4-1, respectively; those of qMS4.2 were fragmented in Fvb4-3, which suggests that some scaffolds were incorrectly assembled in Fvb4-3. qMS4.3 was mapped to chr4X1 of ‘Reikou’ genome assembly r2.3, and qMS4.1 and qMS4.2 were both mapped to chr4Av, which indicates that differentiation of the subgenomes in which both QTLs are located was insufficient in ‘Reikou’ r2.3. Although ‘Camarosa’ genome assembly v. 1.0.a1 is an unphased map, which merges homologous chromosomes into one sequence, ‘Reikou’ genome assembly r2.3 is a phased map, which separates homologous chromosomes. QTL mapping to different reference genomes clearly showed the specific features of each reference genome, and that using different kinds of reference map could accelerate fine mapping and map-based cloning of certain genes of cultivated strawberry.

  • Naoya Yamaguchi, Chika Suzuki, Yoko Yamashita, Mineo Senda
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 467-473
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/27
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    In yellow soybean, severe cold weather causes seed cracking on the dorsal side. Yellow soybeans carry the I or ii allele of the I locus and have a yellow (I) or pigmented (ii) hilum. We previously isolated an additional allele, designated as Ic, of the I locus, and reported that yellow soybeans with the IcIc genotype may be tolerant to cold-induced seed cracking. The Ic allele by itself, however, does not confer high tolerance. The association of a pubescence color gene (T) with suppression of low-temperature-induced seed coat deterioration has been previously reported. In the present study, we tested whether T is effective for the suppression of cold-induced seed cracking using two pairs of near-isogenic lines for the T locus in the iiii or IcIc background. In both backgrounds, the cracked seed rate of the near-isogenic line with the TT genotype was significantly lower than that with the tt genotype, which indicates that T has an inhibitory effect on cold-induced seed cracking. Furthermore, we also showed that gene pyramiding of Ic and T can improve tolerance to cold-induced seed cracking. Our findings should aid the development of highly SC-tolerant cultivars in soybean breeding programs.

  • Kengo Matsumoto, Yuya Ota, Tomohiro Yamakawa, Teppei Ohno, Satomi Seta ...
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 474-483
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/09/03
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    Brown spot (BS) caused by Bipolaris oryzae is a serious disease of rice and decreases grain yield. Breeding for BS resistance is an economical solution but has not hitherto been achieved. To develop a practical BS-resistant variety, we introduced a chromosomal segment including a quantitative trait locus (QTL) for BS resistance, qBSfR11, derived from the BS-resistant local resource ‘Tadukan’, into the genetic background of the high-yielding but susceptible ‘Mienoyume’. Resistance is controlled by a single recessive gene in a 1.3-Mbp region. We named this gene bsr1 (brown spot resistance 1). The near-isogenic line bsr1-NIL had a greater yield with larger grain width than Mienoyume but similar other agronomic traits in fields where BS was mild; it had a significantly lower BS disease score and a 28.8% higher yield in fields where BS was more severe, and it showed resistance to multiple isolates of BS fungus. It showed stable resistance to BS and had excellent agricultural traits in the presence of BS. We developed the bsr1-NIL with resistance to BS and applied it for variety registration to Ministry of Agriculture, Forestry and Fisheries in Japan as ‘Mienoyume BSL’. This is the first report for the BS resistant rice variety bred using marker-assisted selection.

  • Mai Tanokami, Wei Qin Wang, Meimi Yamamoto, Tomomi Hagiwara, Mari Yumo ...
    原稿種別: Research Paper
    2021 年 71 巻 4 号 p. 484-490
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/09/02
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    The soil-borne plasmodiophorid Polymyxa graminis is a vector for Barley yellow mosaic virus (BaYMV), which can severely damage barley plants. Although 22 disease resistance genes have been identified, only a few have been used for breeding virus-resistant cultivars. Recently, BaYMV strains capable of overcoming the effects of some of these genes have been detected. In this study, green fluorescent protein (GFP)-expressing BaYMV was constructed and used to examine viral dynamics in inoculated barley plants. Leaf inoculations resulted in higher infection rates than root or crown inoculations. Additionally, inoculations of some resistant cultivars produced infections that were similar to those observed in a field test. The results of this study indicate that the GFP-expressing virus is a useful tool for visualizing virus replication and dynamics, and for understanding resistance mechanisms.

Note
  • Yuya Ota, Kengo Matsumoto, Yukinori Nakayama, Tomohiro Yamakawa, Teppe ...
    原稿種別: Note
    2021 年 71 巻 4 号 p. 491-495
    発行日: 2021年
    公開日: 2021/10/01
    [早期公開] 公開日: 2021/08/18
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    Rice brown spot (BS), caused by Bipolaris oryzae, causes yield loss and deterioration of grain quality. Using single-nucleotide polymorphism (SNP) markers, we conducted quantitative trait locus (QTL) analysis of BS resistance in backcross inbred lines (BILs) from a cross between an American rice cultivar, ‘Dawn’ (resistant), and ‘Koshihikari’ (susceptible). Four QTLs for BS resistance were detected in a three-year field evaluation, and ‘Dawn’ contributed the resistance alleles at all QTLs. The QTL with the greatest effect, qBSR6-kd, explained 15.1% to 20.3% of the total phenotypic variation. Although disease score and days to heading (DTH) were negatively correlated in all three years, qBSR6-kd was located near a QTL for DTH at which the ‘Dawn’ allele promoted heading. Another BS resistance QTL (qBSR3.1-kd) was unlinked to the QTLs for DTH. Therefore, these two QTLs are likely to be useful for breeding BS-resistant varieties without delaying heading. The other two BS resistance QTLs (qBSR3.2-kd and qBSR7-kd) were located near DTH QTLs at which the ‘Dawn’ alleles delayed heading. The QTLs reported here will be good candidates for developing BS-resistant cultivars.

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