Forest Improvement

Biology

To achieve the objectives of the course unit, the teaching learning process is based on the following teaching methodologies

1. teaching of theoretical-practical classes;

2. Execution of practical work: 1) in the field; 2) in the laboratory and 3) in the nursery;

3. In bibliographic research and analysis of articles and reports on the contents of the course;

4. In the preparation of reports and presentations related to the aspects covered by this curricular unit;

For better consolidation of concepts and implementation of projects students are accompanied weekly in tutorial classes.

It is required the presence of students in class. The minimum attendance is 75% of the number of classes taught.

This Course Unit has the objective of providing the student with knowledge about:

– The chromosomes and heritability units, the genes. DNA and genetic information.

– The relevance of genomics and its application in breeding; Selection assisted by molecular markers; The molecular clock and its relation with speciation and the construction of phylogenetic trees.

– Qualitative genetics and qualitative characteristics; Mendel’s Laws and their extensions; Quantitative genetics and quantitative characteristics, Additive and non-additive effect genes and their relevance to selection and breeding.

– The description of a population; The Heritability and variances due to genotype, environment and interaction; The general fitness to combination and specific fitness to combination and its relation to propagation methods and pollination type.

– The crossing systems and the associated variability; The effect of polyploidy; The evolution factors, and their effect on genetic variability in populations. Population genetics: allelic and genotypic frequencies. Selection and genetic gain; Short and long term improvement and its strategies.

Through the above objectives the student acquires skills, knows and identifies:

– The karyotype, which characterizes each species at the chromosome level. The cytology of the chromosome: the heritability units, the genes and their alleles at the individual and population level; their relation with polymorphism and genetic diversity; and their relevance in breeding and “fingerprinting” of selected individuals.

– DNA and genetic information: coding regions / gene DNA vs non-coding regions and their relative proportion. The relationship between gene with correspondence to a segment of DNA, essential for a specific function (protein/enzyme and RNA synthesis). The central dogma of molecular biology and the genetic code. The relevance of genomics in breeding: the regulation of gene activity and its use in breeding; the highly conservative gene order on chromosomes for various taxonomic families and its relevance and applications; the molecular clock and its relation to the assessment of speciation dates and the construction of phylogenetic trees.

– Qualitative genetics and qualitative traits: discrete phenotypic distribution ( 0 vs 1); control by few genes; reduced environmental effect; Mendel’s Laws and their relationship with Dominant vs recessive effect genes; heritability of qualitative traits and their relationship with breeding, selection and propagation methods; the exceptions / extensions to Mendel’s laws (genes with partial or incomplete Dominance and codominance effect; epistasis; and chromosome linkage group).

– Quantitative genetics and quantitative traits: continuous phenotypic distribution; control by several to large numbers of genes / genes with additive effect; relevant environmental effect; traits in general associated with growth and production / with economic value; their heritability and relation to breeding, selection and propagation methods.

– The description of a population and its sampling: the mean, variance, standard deviation and standard error. The causes of variability / the phenotypic variance function of the variance due to the environment (M), genotypic variance / VG and the variance due to the interaction between G x M. The components of the VG: variance due to genes of additive effect / AV; variance due to genes of dominant effect / VD; variance due to non-allelic interactions or epistasis effects / VI. Heritability in broad and narrow sense and its application to propagation methods and breeding.

– General combining ability/AGC and specific combining ability/AEC, their relation to propagation methods and free vs controlled pollination. The establishment of progeny trials of half sibling and full sibling families. The blocks and the reduction of the effect due to environmental variance. The evaluation of families/clones for a specific environment. The general fitness of the combination and its relation to the reproductive value of the family and the additive variance.

– The crossing systems (autogamy vs allogamy) and their effect on genetic variability in populations. Evolutionary factors that affect the genetic variability of populations: mutation, migration / gene flow, natural selection and genetic drift. Maintenance and use of variability: the in situ vs ex situ genetic variability conservation programs. The dynamic conservation of populations in situ and its relevance to long-term improvement.

– Population genetics: allelic and genotypic frequencies. Population in Hardy-Weinberg equilibrium and the balance of allelic and genotypic frequencies in a population. Hardy-Weinberg equilibrium and the Wahlund principle: the frequency of homozygotes decreases when barriers between populations are broken and its effect on reducing the risk of transmission of recessive traits.

– Short term genetic gain is a function of: 1) the selection characteristics and their heritability; 2) their variability / variance in the population; 3) the number of individuals selected / selection intensity; 4) the selection differential; 5) the propagation methods used; and 6) the environment. The evaluation of the selected phenotypes: a) installation of progeny or clonal trials in complete randomized blocks (reduction of the effect of environmental variance); b) installation in different locations to evaluate the interaction between genotype and environment; and/or c) use of molecular markers (MAS / markers assisted selection). The genetic correlations: 1) between characteristics (pleiotropy – when genes affect several characteristics); 2) between the juvenile and adult states (anticipation in the evaluation of genotypes); and 3) between different environments – interaction between the genotype and the environment (for subsequent clonal or family allocation).

The cytology of the chromosome. DNA and genetic information. Genomics and forest improvement.

Qualitative genetics, qualitative characteristics and Mendel’s Laws. Quantitative genetics.

Heritability and variances due to genotype, environment and their interaction. Combination aptitude (general and specific).

Evolutionary factors, forces affecting genetic variability in populations. Crossover systems and variability.

Population genetics. Population in Hardy-Weinberg equilibrium.

Selection and genetic gain. The improvement and conservation of forest resources. Genetic correlations. The established teaching methodologies seek a clear and effective transmission of the defined course contents, in order to achieve the learning objectives. The stimulation of dialogue and the participation of students in the practical component (field, nursery and laboratory), will allow the students to follow the process of acquiring skills.

The teaching methodologies adopted allow

– Understand the relevance of genomics in breeding.

– Understand the selection for quantitative and/or qualitative traits (genes with additive vs. dominant effect), their relevance in the selection of plant material and subsequent use with different propagation methods (seminal vs. vegetative), their advantages and limitations.

– Understand the relation between Phenotype vs Genotype; the phenotypic variance as a function of the variance due to the environment, the genotypic variance (its components, additive and non-additive) and the respective interaction.

– Understand the relationship between pollination systems and the fitness to combine (general or specific). Understand the relationship between general combining ability, family reproductive value and additive variance.

– Understand the forces/factors of evolution affecting genetic variability in populations and also their relationship to crossing systems.

– Understand the need in the short term to implement selection and directed breeding /hybridization programs and in the long term to conserve genetic resources.

• - Report and discussion - 10.0%
• - Field and laboratory evaluation - 10.0%
• - Written Tests - 80.0%

NAO

Collard, B., Jahufer, M., Brouwer, J., & Pang, E. (2005). An introduction to markers, quantitative trait loci (QTL) mapping and marker-assisted selection for crop improvement: The basic concepts. Euphytica 142, 169- 196.

Commission of Forest Genetic Resources. (2001). Forest Genetic Resources Management and Conservation. France as a case study. INRA, Paris, E. Teissier Cros (ed.)

Eriksson, G.; Ekberg, I., & Clapham, D. (2006). An introduction to forest genetics. SLU. http://vaxt.vbsg.slu.se/forgen/, Uppsala.

White, T.L., Adams, W.T., & Neale, D.B. (2007). Forest Genetics. CAB Internacional Oxfordshire.

Zobel, B., & Talbert, J. (2003). Applied Forest Tree Improvement: Blackburn Press