Displaying all 2 publications

Abstract:
Sort:
  1. Fulltext Marker-assisted selection strategy to pyramid two or more QTLs for quantitative trait-grain yield under drought
    Kumar A, Sandhu N, Dixit S, Yadav S, Swamy BPM, Shamsudin NAA
    Rice (N Y), 2018 May 29;11(1):35.
    PMID: 29845495 DOI: 10.1186/s12284-018-0227-0
    BACKGROUND: Marker-assisted breeding will move forward from introgressing single/multiple genes governing a single trait to multiple genes governing multiple traits to combat emerging biotic and abiotic stresses related to climate change and to enhance rice productivity. MAS will need to address concerns about the population size needed to introgress together more than two genes/QTLs. In the present study, grain yield and genotypic data from different generations (F3 to F8) for five marker-assisted breeding programs were analyzed to understand the effectiveness of synergistic effect of phenotyping and genotyping in early generations on selection of better progenies.

    RESULTS: Based on class analysis of the QTL combinations, the identified superior QTL classes in F3/BC1F3/BC2F3 generations with positive QTL x QTL and QTL x background interactions that were captured through phenotyping maintained its superiority in yield under non-stress (NS) and reproductive-stage drought stress (RS) across advanced generations in all five studies. The marker-assisted selection breeding strategy combining both genotyping and phenotyping in early generation significantly reduced the number of genotypes to be carried forward. The strategy presented in this study providing genotyping and phenotyping cost savings of 25-68% compared with the traditional marker-assisted selection approach. The QTL classes, Sub1 + qDTY 1.1  + qDTY 2.1  + qDTY 3.1 and Sub1 + qDTY 2.1  + qDTY 3.1 in Swarna-Sub1, Sub1 + qDTY 1.1  + qDTY 1.2 , Sub1 + qDTY 1.1  + qDTY 2.2 and Sub1 + qDTY 2.2  + qDTY 12.1 in IR64-Sub1, qDTY 2.2  + qDTY 4.1 in Samba Mahsuri, Sub1 + qDTY 3.1  + qDTY 6.1  + qDTY 6.2 and Sub1 + qDTY 6.1  + qDTY 6.2 in TDK1-Sub1 and qDTY 12.1  + qDTY 3.1 and qDTY 2.2  + qDTY 3.1 in MR219 had shown better and consistent performance under NS and RS across generations over other QTL classes.

    CONCLUSION: "Deployment of this procedure will save time and resources and will allow breeders to focus and advance only germplasm with high probability of improved performance. The identification of superior QTL classes and capture of positive QTL x QTL and QTL x background interactions in early generation and their consistent performance in subsequent generations across five backgrounds supports the efficacy of a combined MAS breeding strategy".

  2. Fulltext Genetic Loci Governing Grain Yield and Root Development under Variable Rice Cultivation Conditions
    Catolos M, Sandhu N, Dixit S, Shamsudin NAA, Naredo MEB, McNally KL, et al.
    Front Plant Sci, 2017;8:1763.
    PMID: 29085383 DOI: 10.3389/fpls.2017.01763
    Drought is the major abiotic stress to rice grain yield under unpredictable changing climatic scenarios. The widely grown, high yielding but drought susceptible rice varieties need to be improved by unraveling the genomic regions controlling traits enhancing drought tolerance. The present study was conducted with the aim to identify quantitative trait loci (QTLs) for grain yield and root development traits under irrigated non-stress and reproductive-stage drought stress in both lowland and upland situations. A mapping population consisting of 480 lines derived from a cross between Dular (drought-tolerant) and IR64-21 (drought susceptible) was used. QTL analysis revealed three major consistent-effect QTLs for grain yield (qDTY1.1, qDTY1.3 , and qDTY8.1 ) under non-stress and reproductive-stage drought stress conditions, and 2 QTLs for root traits (qRT9.1 for root-growth angle and qRT5.1 for multiple root traits, i.e., seedling-stage root length, root dry weight and crown root number). The genetic locus qDTY1.1 was identified as hotspot for grain yield and yield-related agronomic and root traits. The study identified significant positive correlations among numbers of crown roots and mesocotyl length at the seedling stage and root length and root dry weight at depth at later stages with grain yield and yield-related traits. Under reproductive stage drought stress, the grain yield advantage of the lines with QTLs ranged from 24.1 to 108.9% under upland and 3.0-22.7% under lowland conditions over the lines without QTLs. The lines with QTL combinations qDTY1.3 +qDTY8.1 showed the highest mean grain yield advantage followed by lines having qDTY1.1 +qDTY8.1 and qDTY1.1 +qDTY8.1 +qDTY1.3 , across upland/lowland reproductive-stage drought stress. The identified QTLs for root traits, mesocotyl length, grain yield and yield-related traits can be immediately deployed in marker-assisted breeding to develop drought tolerant high yielding rice varieties.
Related Terms
    Try searching for something
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links