Breeding & Genetics

Overview

Plant breeding is the art and science of changing the traits of plants in order to produce desired characteristics. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular techniques.

Plant breeding started with sedentary agriculture and particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years. Initially early farmers simply selected food plants with particular desirable characteristics, and employed these as progenitors for subsequent generations, resulting in an accumulation of valuable traits over time. Gregor Mendel's experiments with plant hybridization led to his establishing laws of inheritance. Once this work became well known, it formed the basis of the new science of genetics, which stimulated research by many plant scientists dedicated to improving crop production through plant breeding. Modern plant breeding is applied genetics, but its scientific basis is broader, covering molecular biology, cytology, systematics, physiology, pathology, entomology, chemistry, and statistics (biometrics).

Classical Breeding

Classical plant breeding uses deliberate interbreeding (crossing) of closely or distantly related individuals to produce new crop varieties or lines with desirable properties. Plants are crossbred to introduce traits/genes from one variety or line into a new genetic background. For example, a mildew-resistant pea may be crossed with a high-yielding but susceptible pea, the goal of the cross being to introduce mildew resistance without losing the high-yield characteristics. Progeny from the cross would then be crossed with the high-yielding parent to ensure that the progeny were most like the high-yielding parent, (backcrossing). The progeny from that cross would then be tested for yield and mildew resistance and high-yielding resistant plants would be further developed. Plants may also be crossed with themselves to produce inbred varieties for breeding. Classical breeding relies largely on homologous recombination between chromosomes to generate genetic diversity. The classical plant breeder may also make use of a number of in vitro techniques such as protoplast fusion, embryo rescue or mutagenesis (see below) to generate diversity and produce hybrid plants that would not exist in nature.

Traits that breeders have tried to incorporate into crop plants in the last 100 years include:

  • Increased quality and yield of the crop
  • Increased tolerance of environmental pressures (salinity, extreme temperature, drought)
  • Resistance to viruses, fungi and bacteria
  • Increased tolerance to insect pests
  • Increased tolerance of herbicides
Projects
2014
An initial set of KASP markers were used for validation of the Illumina Golden Gate Assay (Pv768).
2014
A number of KASP markers were developed based on the genotypes identified under the Lentil 454 Sequencing Project. An initial set were used for validation of the SNP calling before developing the Illumina Golden Gate Assay (Lc1536). An additional 350 KASP primers were then designed for the SNPs that were successfully mapped using data from the GoldenGate array (see Fedoruk et al. 2013).
2014
<p>This <em>Phaseolus vulgaris</em> assembly for the Andean line G19833 was made available by Phytozome as a PRE-RELEASE and has been deprecated in favour of the newest published. This pre-release assembly was used in our Common Bean 454 SNP Discovery Project to anchor the reads for SNP calling and is made available here simply to provide context for that analysis. The main assembly was generated using Newbler version 2.5.3. This is an improved preliminary release of <em>Phaseolus vulgaris</em> that uses all of the ARRA generated data (DOE-JGI, ARRA, and USDA-ARS funding).</p>
2008 to 2013
Phytate is the major storage form of phosphorus in crop seeds, but is not well digested by humans and non-ruminant animals. In addition, phytate chelates several essential micronutrients which are also excreted contributing to phosphorus pollution in the environment. The present study is aimed at biochemical and molecular characterization of two low phytate pea mutant lines, 1-150-81 and 1-2347-144 developed at the Crop Development Centre, University of Saskatchewan in collaboration with Dr. Victor Raboy, USDA, Idaho.
2009 to 2013
Ascochyta blight caused by Mycosphaerella pinodes (MP) is the most important pea disease in Canada and most pea growing regions in the world, often causing serious yield losses. Genetic resistance to ascochyta blight accumulated through two decades of breeding reduces disease severity, however, under cool, wet conditions, the resistance is not sufficient to prevent economic losses. Some accessions of Pisum fulvum, a wild relative of field pea, possess a high level of resistance to ascochyta blight. This project was designed to initiate a long-term strategy for enhancement of ascochyta blight resistance in pea using an integrated genetic improvement approach through interspecific hybridization, careful phenotyping and molecular genotyping.
2012
Lentil seed is a good source of phenolic compounds, which can have health benefits. This project will try to find how different seed coat colours in lentil can be related to the phenolics profile. A fast extraction method and an optimized LC-MS analysis were applied to compare green, gray, tan, and brown seed coat colour lentils. Also, the so called zero-tannin genotypes were compared with the normal ones based upon their phenolic profile. The effect of storage on phenolic profile of lentil seeds was investigated, as well.
2010 to 2012
The objective of this study is to determine the genetic control of several traits in field pea including mycosphaerella blight resistance, lodging resistance and micronutrient concentration by genotyping and phenotyping a recombinant inbred line population which is segregating for these traits.
2010 to 2012
The nutritional value of pea, lentil, chickpea and dry bean grains are highly important for human health. Biofortification, enriching the nutritional contribution of staple crops through plant breeding, is one option that is now widely discussed in the fields of nutrition and public health at the national and international levels.
2011
<p>Preparation of EST data: Sequences were extracted from dbEST and were subjected to quality control screening (vector, E. coli, polyA, T, or CT removal, minimum length = 100 bp, &lt; 3% N). Preparation of transcript (ET) database: All sequences from the appropriate divisions of GenBank (including RefSeq) were extracted. Non-coding sequences were discarded and cDNAs and coding sequences from genomic entries were saved. Sequences and related information (e.g. PubMed links) are stored in the qcGene database (qcGene). Assembly: Cleaned EST sequences and non-redundant transcript (ET) sequences were combined. Using the Paracel Transcript Assembler Program, sequences were assembled into contigs. TCs are consensus sequences based on two or more ESTs (and possibly an ET) that overlap for at least 40 bases with at least 94% sequence identity. These strict criteria help minimize the creation of chimeric contigs. These contigs are assigned a TC (Tentative Consensus) number. TCs may comprise ESTs derived from different tissues. The best hits for TC's were assigned by searching the TC set against a non-redundant amino acid database(nraa) using BLAT. The top five hits based on score were selected and displayed for each TC. Caveats: TCs are only as good as the ESTs underlying them; there may be unspliced or chimeric ESTs and thus TCs. There is still redundancy in the TC set because sequences must match end to end and at a certain percent identity to be combined. Directionality of the TCs should not be assumed. Not all TCs contain protein-coding regions.</p>

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