So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Conservation biology has two threads: the small-population paradigm which deals with the erect of smallness on the persistence of a population, and the declining-population paradigm which deals with the cause of smallness and its cure. The processes relevant to the small-population paradigm are amenable to theoretical examination because they generalize across species and are subsumed by an inclusive higher category: stochasticity. In contrast, the processes relevant to the declining-population paradigm are essentially humdrum, being not one but many. So far they have defied tight generalization and hence are of scant theoretical interest. The small-population paradigm has not yet contributed significantly to conserving endangered species in the wild because it treats an erect (smallness) as if it were a cause

Directions in conservation biology

https://www.fs.fed.us/rm/pubs_other/rmrs_1999_neary_d001.pdf

Fire effects on belowground sustainability: a review and synthesis

We have used a "two-way pseudo-testcross" mapping strategy in combination with the random amplified polymorphic DNA (RAPD) assay to construct two moderate density genetic linkage maps for species of Eucalyptus. In the cross between two heterozygous individuals many single-dose RAPD markers will be heterozygous in one parent, null in the other and therefore segregate 1:1 in their F1 progeny following a testcross configuration. Meiosis and gametic segregation in each individual can be directly and efficiently analyzed using RAPD markers. We screened 305 primers of arbitrary sequence, and selected 151 to amplify a total of 558 markers. These markers were grouped at LOD 5.0, theta = 0.25, resulting in the maternal Eucalyptus grandis map having a total of 240 markers into 14 linkage groups (1552 cM) and the paternal Eucalyptus urophylla map with 251 markers in 11 linkage groups (1101 cM) (n = 11 in Eucalyptus). Framework maps ordered with a likelihood support > or = 1000:1 were assembled covering 95% of the estimated genome size in both individuals. Characterization of genome complexity of a sample of 48 mapped random amplified polymorphic DNA (RAPD) markers indicate that 53% amplify from low copy regions. These are the first reported high coverage linkage maps for any species of Eucalyptus and among the first for any hardwood tree species. We propose the combined use of RAPD markers and the pseudo-testcross configuration as a general strategy for the construction of single individual genetic linkage maps in outbred forest trees as well as in any highly heterozygous sexually reproducing living organisms. A survey of the occurrence of RAPD markers in different individuals suggests that the pseudo-testcross/RAPD mapping strategy should also be efficient at the intraspecific level and increasingly so with crosses of genetically divergent individuals. The ability to quickly construct single-tree genetic linkage maps in any forest species opens the way for a shift from the paradigm of a species index map to the heterodox proposal of constructing several maps for individual trees of a population, therefore mitigating the problem of linkage equilibrium between marker and trait loci for the application of marker assisted strategies in tree breeding.

https://www.genetics.org/content/genetics/137/4/1121.full.pdf

Genetic linkage maps of Eucalyptus grandis and Eucalyptus urophylla using a pseudo-testcross: mapping strategy and RAPD markers

2.3 Changes in soil temperatures after fire 3. Influence of the products of vegetation burning (ash and heat), on the soil environment, and their relation to nutrient availability 3. 1 The soil as an environment for biological activities and nutrient transformations 3.2 The ash component 3.2.1 Relationship between ash deposition and soil fertility 3.2.2 Effects of ash on nutrient cycling and soil chemical and biological processes 3.2.2.1 Ash formation 3.2.2.2 Ash return and properties 3.2.2.3 Nutrient return in ash, and the effect of ash on soil chemical properties 3.2.2.4 Influence of ash on soil biological processes 3.3 The heat component 3.3.1 General introduction 3.3.2 Plant growth in heated and sterilized soils 3.3.3 Effect on soil physical properties 3.3.4 Influence of heat on soil chemical properties 3.3.4.1 Changes in properties other than N compounds 3.3.4.2 Non-biological changes in soil N fractions 3.3.5 Biological changes in heated soils 3.3.6 Non-biological gas exchange in heated soils

Modification of the soil environment by vegetation fires, with particular reference to nitrogen transformations: A review

Introduction 1. Eucalypts natural and planted 2. Genetic resources of eucalypts 3. Matching species and provenances to site 4. Testing species and provenances 5. Eucalyptus camaldulensis 6. Eucalyptus deglupta 7. Eucalyptus delegatensis 8. Eucalyptus fastigata 9. Eucalyptus globulus 10. Eucalyptus grandis and E. saligna 11. Eucalyptus nitens 12. Eucalyptus obliqua 13. Eucalyptus regnans 14. Eucalyptus tereticornis 15. Eucalyptus urophylla 16. Eucalyptus viminalis 17. Breeding strategies and breeding plans 18. Reproductive biology of eucalypts 19. Selection and breeding 20. Seed production 21. Mass vegetative propagation 22. Looking ahead Glossary References Index

Eucalypt Domestication and Breeding

Experimental Design and Analysis for Tree Improvement provides a set of practical procedures to follow when planning, designing and analysing tree improvement trials.

Using many fully-worked examples, it outlines how to: design field, glasshouse and laboratory trials; efficiently collect data and construct electronic data files; pre-process data, screening for data quality and outliers; analyse data from single and across-site trials using either GenStat or SAS; and interpret the results from statistical analyses.

The authors address the many practical issues often faced in forest tree improvement trials and describe techniques that will give conclusive results with the minimum expense. The techniques provided are applicable to the improvement of not only trees, but to crops in general.

Building on the success of the first edition, this new edition has been fully revised and updated to relate to the latest commercially-available software packages for design generation (CycDesigN) and data pre-processing and automated generation of programs for statistical analysis (DataPlus). For analysis, it now provides both GenStat and SAS programs as generated by DataPlus.

Experimental Design and Analysis for Tree Improvement

Plants encounter a broad range of natural enemies and defend themselves in diverse ways. The cost of defense can be reduced if a plant secondary metabolite confers resistance to multiple herbivores. However, there are few examples of positively correlated defenses in plants against herbivores of different types. We present evidence that a genetically variable chemical trait that acts as a strong antifeedant to mammalian herbivores of Eucalyptus also deters insect herbivores, suggesting a possible mechanism for cross-resistance. We provide field confirmation that sideroxylonal, an important antifeedant for mammalian herbivores, also determines patterns of damage by Christmas beetles, a specialist insect herbivore of Eucalyptus. In a genetic progeny trial of Eucalyptus tricarpa, we found significant heritabilities of sideroxylonal concentration (0.60), overall insect damage (0.34), and growth traits (0.30–0.53). Population of origin also had a strong effect on each trait. Negative phenotypic correlations were observed between sideroxylonal and damage, and between damage and growth. No relationship was observed between sideroxylonal concentration and any growth trait. Our results suggest that potential for evolution by natural selection of sideroxylonal concentrations is not strongly constrained by growth costs and that both growth and defense traits can be successfully incorporated into breeding programs for plantation trees.

/pdf/heritable-variation-in-the-foliar-secondary-metabolite-5b046a3sen.pdf

Heritable variation in the foliar secondary metabolite sideroxylonal in Eucalyptus confers cross-resistance to herbivores.

Vietnam has established 1.1 million ha of acacia plantations for wood production, managed on 5- to 10-year rotation cycles. Nearly 50% of the resource is managed by small growers holding 1–5 ha woodlots. Acacia plantations have emerged as an important resource for supporting the rural economy and national export revenue. Given the range of climate, terrain, soils, management inputs and skills, plantation productivity varies from 10 to 25 m 3 ha −1 y −1 . Future growth of this sector will depend on improving and sustaining production from the current land base, much of which is already in its second or third rotation. Although studies on sustainable production are limited, available information suggests good prospects for increasing production and improving soils. Breeding has produced genotypes with potential for increasing growth, but this has not generally been matched by sustainable soil and stand management practices. Several current practices warrant immediate change, based on sustainability principles. Internationally, research has established the need for conserving site resources and other judicious management practices. Vietnam should adopt these principles and develop locally appropriate practices to implement them. Greater efforts are required on surveillance of major diseases and tree breeding to improve disease resistance. Because acacia plantations deliver high economic benefits and there are opportunities for improving productivity, an R&D strategy focused on underpinning sustainable management and application would serve the nation well. Key elements include commitments to adaptive  research for achieving impacts, effective partnerships between public and private organisations, fostering an integrated approach to management, and special attention to the needs of smallholder growers. Keywords : Acacia, research, risks, strategy, system integration, Vietnam

Acacia plantations in Vietnam: research and knowledge application to secure a sustainable future

SUMMARY Losses to the atmosphere of four nutrient elements, phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg), caused by slash burning a logged-over mixed forest coupe in the Florentine Valley in Tasmania, were estimated by weighing and sampling the slash on marked plots before and after the fire. The estimated losses, in kg ha—1, were: P—10, K—51, Ca—100 and Mg—37. As a percentage of the nutrients in the fuel consumed, the losses were: P—18%, K—17%, Ca—12%, Mg—29%.

Chris Harwood

Papers

Eucalypt Domestication and Breeding

Experimental Design and Analysis for Tree Improvement

Heritable variation in the foliar secondary metabolite sideroxylonal in Eucalyptus confers cross-resistance to herbivores.

Acacia plantations in Vietnam: research and knowledge application to secure a sustainable future

Atmospheric Losses of Four Plant Nutrients During a Forest Fire