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Title: Genetic studies and improvement of Pinus caribaea morelet
Author: Zheng, Yongqi
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1996
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Pinus caribaea is a tropical pine that is widely planted as an exotic. It is an important plantation species for industrial purposes in China. The objectives of this thesis was to collect basic information on genetic variation, breeding system and performance of a range of seed sources which have potential for incorporation into the Chinese breeding programme. Isozyme variation was studied in natural populations of two geographically separated varieties P. caribaea var. caribaea and P. caribaea var. bahamensis, and in exotic populations of the varieties from China and Australia respectively. There was significant genetic differentiation between the two varieties. Within the varieties, populations of var. bahamensis were more differentiated than those of var. caribaea. Exotic populations for both varieties experience higher inbreeding than natural populations. With var. bahamensis, the Australian population was genetically similar to natural populations. However there were large genetic differences between the Chinese population and the natural population of both var. caribaea and var. bahamensis. The Chinese material was identified as a distinct species by the use of chloroplast DNA variation. Mating systems in natural populations and seed orchard populations of var. caribaea were analysed using isozyme markers. Both single and multi locus estimates of outcrossing rate were significantly smaller than 1.0 (complete outcrossing) in the island population, but were not significantly less than 1.0 in mainland populations and the seed orchard population, indicating that stronger inbreeding exists in the island population. The small differences between single and multi locus estimates suggest that the inbreeding detected within the variety is caused by true selfing rather than consanguineous mating. The selfing rates ranged from 10.6% in the island population to 1.5% in the seed orchard based on 5 loci assayed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available