Báo cáo nghiên cứu khoa học " Genetic Improvement of Forest Trees " pot

Genetic Improvement of Forest Trees Khongsak Pinyopusarerk CSIRO/Ensis-Genetics Canberra, Australia Why Do We Need Tree Improvement? To develop new plantations superior to their predecessors in one or several key economic traits Variation within a Species Offer potential for improvement through selection and breeding between provenances between families Basic Elements of Tree Improvement • • • • • Well defined strategy and plan Clear objectives Hierarchy of populations Selection and mating Personnel and funding Well Defined Strategy and Plan • Improvement strategy – the framework of ideas Essential elements are: (a) Type of selection and mating, starting with a broad genetic base (b) An efficient system for mass propagation of outstanding selected individuals either as seed or cuttings • Improvement plan – a detailed work plan to implement the chosen strategy Clear objectives Stem form Which traits to be improved? Disease resistance Vigour Choosing traits for measurement and assessment ? ? ? ? ? • • • • • • • • • • • • • • • • • • • survival dbh height stem volume wood density, colour timber strength, stiffness timber defects pulp yield fibre length stem straightness axis persistence/forking branch thickness branch angle pest and disease resistance growth stress tension wood fodder production fodder value other traits? Activity Cycle – Hierarchy of Four Populations Base population BASE Breeding population progeny tests mating select trees Propagation population selection Production population seed plantations orchards/ mass clone banks propagation Activity cycle for tree breeding Selection Base Population Propagation Population (seed orchards) Crossing Breeding Population Planting stock for plantations Selection and Mating • • • • Key activities in breeding Progeny trials to assess variation within a species Open pollination or controlled pollination Minimising potential of inbreeding Conditions for Production of Inbred Seed Self-fertilization Pollen Isolated tree Impact of Inbreeding Conditions for production of high-quality seed Pollinators Outcrossing • Wide genetic base - most trees unrelated • Good cross-pollination • Outcrossing between unrelated trees Controlled Pollination Improvement Program of Acacia auriculiformis Good progress in Thailand and Vietnam Hybrids • Natural or artificial • Heterosis in F1 generation Hybrids Uniformity of F1 generation Segregation of F2 and subsequent generations Seed Production Area Low-cost technology • Establish stands with a mix of 50100 unrelated seed parents from many sources • Start at close spacing to allow heavy and early selective thinning • Produce seed of somewhat improved quality • Outstanding individuals may be used for clonal forestry after field testing Concluding Remarks • Tree improvement is long-term investment and must be well planned and executed • Tree improvement must be on-going with subsequent breeding cycles • Need to improve skills of staff • Abundant production of very high quality seed is key component of tree improvement ... pollination Minimising potential of inbreeding Conditions for Production of Inbred Seed Self-fertilization Pollen Isolated tree Impact of Inbreeding Conditions for production of high-quality seed... Pollinators Outcrossing • Wide genetic base - most trees unrelated • Good cross-pollination • Outcrossing between unrelated trees Controlled Pollination Improvement Program of Acacia auriculiformis... executed • Tree improvement must be on-going with subsequent breeding cycles • Need to improve skills of staff • Abundant production of very high quality seed is key component of tree improvement