Molecular breeding

About: Molecular breeding is a research topic. Over the lifetime, 2120 publications have been published within this topic receiving 56908 citations.

Precision breeding with genomic tools: A decade long journey ofmolecular breeding in rice

Abstract: Plant breeding helps in recombining and fixation of desirable alleles which enables the development of improved varieties with better productivity. Though classical plant breeding has contributed enormously in achieving genetic gains in different crops including rice, the challenges imposed by resource constraints as well as greater anticipated demand need better tools to meet the expectations. Molecular breeding which uses modern genomic tools integrated with plant breeding offers enormous potential for improvement of crop varieties. The present review focusses on the achievements of ICAR-IARI in molecular breeding in rice wherein as many as eight rice varieties were incorporated with genes governing resistance/tolerance to different traits and released for commercial cultivation in India. The various factors which enabled the successful integration of molecular breeding including development of infrastructure, human resources and the genetic and genomic resources have been discussed in detail. All the examples of translational research are from the marker assisted backcross breeding strategy, which limits the scope for achieving yield gains. In the foregoing discussion, the challenges and the opportunities for implementation of molecular breeding in rice to realize the full potential of these tools in plant breeding are discussed based on the decade long experience, which may be valuable for other crops as well.

Genome-wide development of simple sequence repeats database for flax (Linum usitatissimum L.) and its use for genetic diversity assessment

Abstract: Flax (Linum usitatissimum L.) is an important industrial crop and is widely cultivated in North America, Europe, and China for its fiber and oil. Identifying flax molecular markers is a vital step towards improving flax yield and quality via marker-assisted breeding. Simple sequence repeat (SSR) markers have proven to be the most valuable type of genetic marker for molecular breeding and genetic diversity studies. However, the development of genome-wide SSRs in flax has not yet been reported, which limits their use in molecular breeding. In this study, we screened 25,871 SSR motifs from L. usitatissimum, mainly consisting of trinucleotide (52.8%) and dinucleotide (36.1%) repeats. Based on the 24,375 SSR motifs, 71,184 primers pairs of SSR markers were designed for the flax genome, covering the whole genome at a density of 225.3/Mb. Furthermore, 96 pairs of SSR markers from different chromosomes were used to assess a panel of 26 flax accessions obtained from different parts of the world. The 21 SSR markers exhibited polymorphisms across the 26 flax accessions, and the flax varieties were accurately clustered into two groups and two subgroups corresponding to their type (wild species or cultivar) and use (fiber or oilseed). This study demonstrates the potential value in analyzing genetic diversity in flax, and the large-scale development of SSR markers developed in this study will facilitate future molecular analyses in flax.

Omics in plant breeding

Abstract: Description: Computational and high–throughput methods, such as genomics, proteomics, and transcriptomics, known collectively as –omics, have been used to study plant biology for well over a decade now. As these technologies mature, plant and crop scientists have started using these methods to improve crop varieties. Omics in Plant Breeding provides a timely introduction to key omicsbased methods and their application in plant breeding. Omics in Plant Breeding is a practical and accessible overview of specific omics–based methods ranging from metabolomics to phenomics. Covering a single methodology within each chapter, this book provides thorough coverage that ensures a strong understanding of each methodology both in its application to, and improvement of, plant breeding. Accessible to advanced students, researchers, and professionals, Omics in Plant Breeding will be an essential entry point into this innovative and exciting field. A valuable overview of high–throughput, genomics–based technologies and their applications to plant breeding Each chapter explores a single methodology, allowing for detailed and thorough coverage Coverage ranges from well–established methodologies, such as genomics and proteomics, to emerging technologies, including phenomics and physionomics Aluízio Borém is a Professor of Plant Breeding at the University of Viçosa in Brazil. Roberto Fritsche–Neto is a Professor of Genetics and Plant Breeding at the University of São Paulo in Brazil.

Identification and molecular mapping of indica high‐tillering dwarf mutant htd4, a mild phenotype allelic mutant of D14 in rice (Oryza sativa L.)

Abstract: Metabolism of strigolactones (SLs) can improve the efficiency of nutrient use by regulating the development of roots and shoots in crops, making them an important research focus for molecular breeding. However, as a very important plant hormone, the molecular mechanism of SL signal transduction still remains largely unknown. In this study, we isolated an indica high-tillering dwarf mutant 4 (htd4), a spontaneous mutant of rice, from the restorer line Gui99. Mapping and sequencing analysis showed that htd4 was a novel allelic mutant of D14, in which a single base substitution forms a premature termination codon. Quantitative RT-PCR analyses revealed that expression levels of the genes D10, D17, D27, D3 and D14 increased significantly, while expression of D53 decreased in htd4, compared with the wild type. A subcellular localisation assay showed that the mutant of D14 in htd4 did not disturb the normal localisation of D14 proteins. However, a BiFC assay suggested that the mutant-type D14 could not interact with D3. Additionally, compared with other D14 allelic mutants, htd4 was the first mutant of D14 discovered in indica, and the differences in many yield traits such as plant height, seed-setting rate and grain sizes between htd4 and the wild type were less than those between other D14 allelic mutants and the wild type. Therefore, htd4 is considered a mild phenotype allelic mutant of D14. We conclude that the absence of functional D14 caused the high-tillering dwarf phenotype of htd4. Our results may provide vital information for research on D14 function and the application of htd4 in molecular breeding.

QTL Genetic Mapping Study for Traits Affecting Meal Quality in Winter Oilseed Rape (Brassica Napus L.)

Abstract: Rapeseed (Brassica napus L.) meal is an important source of protein, but the presence of anti-nutritional compounds, such as fibre and glucosinolates, still limits its use as a livestock feed. Understanding the genetic basis of seed fibre biosynthesis would help to manipulate its content in seeds of oilseed rape. Here, we applied high-resolution skim genotyping by sequencing (SkimGBS) and characterised 187,835 single-nucleotide polymorphism (SNP) markers across a mapping population subsequently used for a genetic mapping study (R/qtl). This approach allowed the identification of 11 stable QTL related to seed quality traits and led to the identification of potential functional genes underlying these traits. Among these, key genes with a known role in carbohydrate metabolic process, cell wall, lignin, and flavonoid biosynthesis, including cellulase GH5, TT10/LAC15, TT4, and SUC2, were found. This study furthers the understanding of the molecular mechanisms underlying seed fibre content and provides new markers for molecular breeding in B. napus.