Báo cáo nghiên cứu nông nghiệp " Terms Commonly Used in Tree Improvement " doc

Terms Commonly Used in Tree Improvement Khongsak Pinyopusarerk CSIRO/Ensis-Genetics Canberra, Australia Population • A community of interbreeding individuals. No degree of relationship is assumed. • The term “Stand” is often used synonymously. Provenance • Geographic location where seed was collected. • Refers to natural forests, not plantations. • Provenance boundaries not always clear-cut, often one of judgment and opinion. • Provenance may have different genetic adaptation. 130° 140° 10° 20° 0500 Kilometres 32 31 30 29 28 27 25 26 1 6 1 9 22 15 24 23 21 17 18 14 13 1-12 20 WA NT QLD Land race • Introduced trees that are adapted to an environment after several generations • Advantage Natural selection helps land races adapt to a new environment • Disadvantage May not be from the best natural provenances or come from very small genetic base Family • Individuals with parents in common • Half-sib family One common mother, father unknown • Full-sib family Both parents in common Generated by artificial (controlled) pollination Progeny • Trees produced from the seed of a known parent. • Progeny tests are established to determine the genetic worth of the parent trees. • Testing of vegetative propagules (e.g. grafted or cutting materials) is also a progeny test, but often called “clonal test”. Genotype • The genetic potential of the tree when environmental factors are excluded, i.e. only determined by the genes of the tree. • Genotype is determined chiefly from performance of progeny and other relatives. Phenotype • The tree as we see it. • Phenotype is determined by the genotype (G) plus the environment (E). P = G x E • Similar phenotypes do not necessary breed alike. In natural stand phenotype is influenced by the environment in which the trees are growing. When growing in plantations and under similar environmental conditions, superior phenotypes tend to have good genetic potential. [...]... identical individual trees (ramets) produced by vegetative propagation from founder tree (ortet) One clone Ortet (superior tree in field trial) Vegetative propagation (Cuttings, grafts, or micropropagation) Ramets Clone These trees were propagated by cuttings Ortet The original plant from which a clone has been derived Ramet An individual member of a clone In breeding • Production of offspring by mating... offspring by mating between closely related trees, usually by Selfing • This procedure if carried out for a number of generations will expose undesirable, recessive characters Outcrossing • Production of offspring by mating between unrelated trees or distantly related trees Roguing • Systematic removal of undesirable individuals from a population • Synonym with “culling” Heritability (h2) • Measure of proportion... Heritability (h2) • Measure of proportion of variation due to genetics (ranges from 0 to 1) • Apply only to a particular population growing in a particular environment • Usually within an expected range Growth: h2 = 0.15 – 0.25 (moderate) Wood density: h2 = 0.40 – 0.60 (high) Branching : h2 = 0.05 – 0.10 (low) . Terms Commonly Used in Tree Improvement Khongsak Pinyopusarerk CSIRO/Ensis-Genetics Canberra, Australia Population • A community of interbreeding individuals. No degree. clone Clone Clone These trees were propagated by cuttings. Ortet The original plant from which a clone has been derived. Ramet An individual member of a clone. In breeding • Production of offspring by mating. environment in which the trees are growing. When growing in plantations and under similar environmental conditions, superior phenotypes tend to have good genetic potential. Genetically identical individual