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
2013 to 2016
As production of the dry bean is moving towards short season growing regions such as Alberta and Saskatchewan, it is becoming increasingly important to find a way to develop abiotic stress tolerances for the dry bean. Through the incorporation of genes from other species, the stress tolerance capabilities of the dry bean will increase, making it less sensitive to its surrounding climate. The tepary bean was decided upon as the best genetic donor for improvement to the dry bean, and is now being evaluated in Saskatchewan and its international partners.
2016
<p>&nbsp; &nbsp; We have many different types of lentil grown in over 50 countries around the world.&nbsp; The timing to grow the crop is different depending on where you are.&nbsp; In Canada, lentil is sown in May and harvested in August.&nbsp; Whereas in Nepal, lentil is sown in October and harvested in February the year after.&nbsp; In Mediterranean countries such as Italy, lentil is sown in October but won't be harvested until May/June.</p><p>&nbsp; &nbsp; Most lentil varieties only perform well under a specific climate and fail when they are grown in under a different climate.&nbsp; Yield is closely related to adaptation and that is why breeders tend to use only a few local varieties in their crosses.&nbsp; To allow breeders to expand their choices, we need to know how different lentils interact and adapt to different environments, i.e. changing daylength and temperature over the growing season.&nbsp; Better understanding of the genetic mechanism that affects how lentil grow and mature in a specific climatic condition will help breeders to more effectively choose the lines in their crosses.</p>
2013 to 2016
Our approach to sequencing the lentil genome is two-fold. First, we are generating a high quality draft genome for a single lentil genotype (CDC Redberry), including bulk sequencing, assembly of chromosomal ‘pseudomolecules’, and gene prediction and annotation. Secondly, we are re-sequencing various lentil accessions from around the globe to reveal the breath of genetic potential present in our germplasm resources. The outcome will give us i) an understanding of how modern breeding has re-shaped the lentil genome, ii) identification of genes and genomic interval that control agronomic traits, and iii) discovery of many genetic polymorphisms for future marker development, that together will add considerable resources to the breeder’s toolbox for lentil genetic improvement. More importantly, the results of this project will allow us to leverage knowledge of important trait based on conservation of genome-based features with other legume crops (such as Medicago and chickpea).
2013 to 2016
Lentils are seen as a source for essential vitamins and minerals for human nutrition, but due to the high anti-nutritional factors of raffinose family oligosaccharides the consumption of lentils are being limited. Other methods to lower the levels of these RFOs are costly, and that is why an alternative strategy to develop varieties of lentil with lower levels is being implemented.
2013 to 2015
The objectives of this study are to determine the effect of genotype and environment on iron bioavailability in a set of five pea varieties differing in phytate concentration using the Caco-2 mammalian cell bioassay, to determine whether iron bioavailability in field pea is heritable by evaluating recombinant inbred lines differing in phytate concentration using the Caco-2 mammalian cell bioassay, and to determine the effect of the pea low phytate trait on chicken performance and iron bioavailability in chicken.
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
This Phaseolus vulgaris 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 Phaseolus vulgaris that uses all of the ARRA generated data (DOE-JGI, ARRA, and USDA-ARS funding).

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