| Eucalypts have been long introduced and planted in China. They could provide multitude of products and services and play an important role for supplied industrial woods in southern China. To promote the orderly development of the woody paper industry, the National Government has legislated a series of industry policies in recent years. This has resulted in investment by many large foreign companies, together with some state-run and private enterprises in establishment of eucalypt plantations for the paper and pulp industries. The preferred species for this new industry is Eucalyptus urophylla. Because the plantations are being established over a wide geographical range in this region, there is a need for further studies on tree breeding and improvement to provide new varieties and mass improved seeds. This thesis draws on nearly 10 years of research on provenance -family testing, regional progeny testing and establishment and management of seed orchard supported by two World Bank projects (NAP, FRDPP). The objectives of the research were twofold, firstly, to develop new varieties and improved seeds, and secondly, to develop and implement a breeding strategy for E. urophylla under the integrative forest and paper industry. The main results are given below.(1) Through screening trials of E. urophylla provenances - families with multiple selection for growth, stem form and wind-resistance, superior families with good adaptability and superior in stem volume were selected at age 6 years. Provenances 14534, 14533, 15089 (from Mt. Egon Flores Island Indonesia) were the best, followed by 17573, 17572 and 17565 (from Andalan IND, Iling Gele IND and Lewotobi IND respectively) and then 12895 (from Mt. Mandiri IND). Correlation analysis showed that there was no significant interaction between the growth traits (height, DBH and stem volume) and the wood basic density. However, in terms of phenotype and genotype, there were strong, or extremely strong positive interactions between these growth traits with other traits. Other positive correlations were between wood basic density and wind-resistance character, between survival and height and DBH. Three selection methods, combination, family and mass, were applied to evaluate and screen superior materials from 21 provenances and 220 families. The results demonstrated that breeding populations using the combined selection had a stable positive development of all examined traits and characters, which indicated that this breeding practice was better than the others. The newly established breeding population consisted of 152 superior singe trees, which were originally from 12 provenances and 38 superior families, respectively, taking up 57.14% and 17.27% of experimental materials.(2) The progenies of 33 families belonging to the Mt. Egon Flores Island provenances 14534,14531, 16682 and 17567 were all verified to be adaptable and fast growing in 5 sites of progeny testing trials for the open-pollinated families of E. urophylla seedling seed orchards. Among them, 76.74% were superior families. Four types of families were classified: high production and stabile, high production and non-stabile, average production and stabile, low production and high stabile, based on the evaluation theory of two parameters (and) by Eberhart and Russell. This information provides guidance for the establishment of the primary seed orchards by thinning the inferior and reserving the superior trees. At the same time, it is evidential for the further management of the SSOs to orientate development and classifying superior seeds for variant ecological afforestation areas. The results are pertinent for screening parent materials for the first clonal seed orchards.(3) Two types of seed orchards ( and ) were established respectively by the forward selection and backward selection, on the basis of the evaluation of 3-year old provenances and family trials of E. urophylla. Thirty-eight families (84.4% of the total) in produced higher stem volume than those of the control No.1 (CK1), and 39 famil...
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