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Addis Ababa University (2012)

Phenology and Genetic Diversity of Boswellia Papyrifera (Del.) Hochst. Populations of Metema District as Revealed by ISSR Markers

Zinaw, Abush

Titre : Phenology and Genetic Diversity of Boswellia Papyrifera (Del.) Hochst. Populations of Metema District as Revealed by ISSR Markers

Auteur : Zinaw, Abush

Université de soutenance : Addis Ababa University

Grade : Master of Science in Biology (Applied Genetics 2012

Résumé
Boswellia papyrifera (Del.) Hochst. (family Burseraceae), is one of the key plant species in the drylands of the Horn of Africa. Unregulated extraction of gums and resins and land use change are among the main factors that threatened this dry land forest. This plant is a culturally and ecologically relevant species that is showing symptoms of decline due to anthropogenic factors. The study was done on five populations of B. papyrifera from Metema zone, Northern Ethiopia. Inter-Simple Sequence Repeat markers (ISSR) were used to estimate genetic diversity among and within five populations of Boswellia papyrifera collected from Zebach Bahir, Das Gundo, Gubay, Shinfa and Agam Wuha sites. Five selected ISSR primers yielded 39 reproducible bands from 64 individuals studied. All the loci were found to be polymorphic. The total genetic diversity (GD) and Shannon’s diversity information index (I) for entire populations showed fairly high to medium values, 0.42, and 0.60, respectively. The individuals from Zebach Bahir site showed the highest level of gene diversity, 0.42 ; while the least variability showed by Agam Wuha populations with 0.25. Analysis of Molecular Variance showed that the within populations variation was higher (76%) than among population variation (24%). UPGMA analysis revealed one major group and two outliers (Gubay and Agam Wuha). This major cluster again forked into two sub-groups, one group containing Das Gundo while the second group contained Zebach Bahir and Shinfa populations. NJ analysis, based on individuals of Boswellia, showed three distinct clusters and two sub-clusters within the second and third major clusters. In 3D, most of Agam wuha and Gubay individuals tended to form their own separate grouping, while individuals from Zebach Bahir, Das Gundo and Shinfa were inter-mixed and formed a separate group from the other populations. Studies were carried out on the phenology, and pollination ecology of B. papyrifera. The trees remain leafless during the entire period of flowering and fruiting. The inflorescence is a terminal raceme and produces 8-15 bisexual flowers, but it might produce up to 60 flower buds. Moreover, during maximum flowering period on average 14.5 inflorescences per branch were recorded. Flowers offer nectar and pollen as rewards to floral visitors. The honey bee is found to be the effective and frequent pollinator. Each flower is visited by an average number of 6.35 insect visitors every 15 minutes and, on average, each insect visitor spents 5.8 seconds on a flower. High to moderate level of variation was observed with populations of Metema, this indicated the needs for urgent conservation attention.

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Page publiée le 21 juin 2022